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+ font-size: 12px; + font-style: italic; +} + +p.releaseinfo { + font-size: 100%; + font-weight: bold; + font-family: Verdana, Arial, helvetica, sans-serif; + padding-top: 10px; +} + +p.pubdate { + font-size: 120%; + font-weight: bold; + font-family: Verdana, Arial, helvetica, sans-serif; +} + +span.productname { + font-size: 200%; + font-weight: bold; + font-family: Verdana, Arial, helvetica, sans-serif; +} diff --git a/spring-integration-reference/images/cafe-demo.png b/spring-integration-reference/images/cafe-demo.png new file mode 100644 index 0000000000..e97316d5a2 Binary files /dev/null and b/spring-integration-reference/images/cafe-demo.png differ diff --git a/spring-integration-reference/images/channel.png b/spring-integration-reference/images/channel.png new file mode 100644 index 0000000000..25e3458dca Binary files /dev/null and b/spring-integration-reference/images/channel.png differ diff --git a/spring-integration-reference/images/handler-endpoint.png b/spring-integration-reference/images/handler-endpoint.png new file mode 100644 index 0000000000..8a7adfe50c Binary files /dev/null and b/spring-integration-reference/images/handler-endpoint.png differ diff --git a/spring-integration-reference/images/handler.png b/spring-integration-reference/images/handler.png new file mode 100644 index 0000000000..f1398d5d36 Binary files /dev/null and b/spring-integration-reference/images/handler.png differ diff --git a/spring-integration-reference/images/logo.png b/spring-integration-reference/images/logo.png new file mode 100644 index 0000000000..a9f6d959e7 Binary files /dev/null and b/spring-integration-reference/images/logo.png differ diff --git a/spring-integration-reference/images/message-bus.png b/spring-integration-reference/images/message-bus.png new file mode 100644 index 0000000000..f7b72f5943 Binary files /dev/null and b/spring-integration-reference/images/message-bus.png differ diff --git a/spring-integration-reference/images/message.png b/spring-integration-reference/images/message.png new file mode 100644 index 0000000000..8c08501d80 Binary files /dev/null and b/spring-integration-reference/images/message.png differ diff --git a/spring-integration-reference/images/router.png b/spring-integration-reference/images/router.png new file mode 100644 index 0000000000..a45966c2e4 Binary files /dev/null and b/spring-integration-reference/images/router.png differ diff --git a/spring-integration-reference/images/source-endpoint.png b/spring-integration-reference/images/source-endpoint.png new file mode 100644 index 0000000000..4fa95e0198 Binary files /dev/null and b/spring-integration-reference/images/source-endpoint.png differ diff --git a/spring-integration-reference/images/source.png b/spring-integration-reference/images/source.png new file mode 100644 index 0000000000..bec59cf7b3 Binary files /dev/null and b/spring-integration-reference/images/source.png differ diff --git a/spring-integration-reference/images/target-endpoint.png b/spring-integration-reference/images/target-endpoint.png new file mode 100644 index 0000000000..dd4b5787d9 Binary files /dev/null and b/spring-integration-reference/images/target-endpoint.png differ diff --git a/spring-integration-reference/images/target.png b/spring-integration-reference/images/target.png new file mode 100644 index 0000000000..80362dac21 Binary files /dev/null and b/spring-integration-reference/images/target.png differ diff --git a/spring-integration-reference/ivy.xml b/spring-integration-reference/ivy.xml new file mode 100644 index 0000000000..3e57b0496e --- /dev/null +++ b/spring-integration-reference/ivy.xml @@ -0,0 +1,23 @@ + + + + + + + + + + + + + + + + + + + + diff --git a/spring-integration-reference/src/aggregator.xml b/spring-integration-reference/src/aggregator.xml new file mode 100644 index 0000000000..483ef00486 --- /dev/null +++ b/spring-integration-reference/src/aggregator.xml @@ -0,0 +1,519 @@ + + + + Aggregator + +
+ Introduction + + Basically a mirror-image of the Splitter, the Aggregator is a type + of Message Handler that receives multiple Messages and combines them into + a single Message. In fact, Aggregators are often downstream consumers in a + pipeline that includes a Splitter. + + Technically, the Aggregator is more complex than a Splitter, because + it is required to maintain state (the Messages to-be-aggregated), to + decide when the complete group of Messages is available. +
+ +
+ Functionality + + The Aggregator combines a group of related messages, by correlating + and storing them, until the group is deemed complete. At that point, the + Aggregator will create a single message by processing the whole group, and + will send that aggregated message as output. + + An important aspect of + implementing an Aggregator is providing the logic that has to be executed + when the aggregation (creation of a single message out of many) takes + place. + + In Spring Integration, the grouping of the messages for aggregation + is done by default based on their CORRELATION_ID message header (i.e. the + messages with the same CORRELATION_ID will be grouped together). However, + this can be customized, and the users can opt for other ways of + specifying how the messages should be grouped together, by using a + CorrelationStrategy (see below). + + Another important concern is, what happens if + late messages arrive after the aggregation has taken place? In this case, + the user needs to be able to decide whether they should be + discarded or not. +
+ +
+ Programming model + + The Aggregation API consists of a number of classes: + + + + The interface MessageGroupProcessor and related + base class AbstractAggregatingMessageGroupProcessor and its + subclass MethodInvokingAggregatingMessageGroupProcessor + + + + The ReleaseStrategy interface and its default + implementation SequenceSizeReleaseStrategy + + + + The CorrelationStrategy interface and its default + implementation HeaderAttributeCorrelationStrategy + + + +
+ CorrelatingMessageHandler + + The CorrelatingMessageHandler is a + MessageHandler implementation, encapsulating the common + functionalities of an Aggregator (and other correlating use cases), which are: + + + correlating messages into a group to be aggregated + + + maintaining those messages until the group is complete + + + deciding when the group is in fact complete + + + processing the completed group into a single aggregated message + + + recognizing and responding to an expired group + + + The responsibility of deciding how the messages should be grouped together + is delegated to a CorrelationStrategy instance. The responsibility + of deciding whether the message group can be released is delegated to a + ReleaseStrategy instance. + + Here is a brief highlight of the base + AbstractAggregatingMessageGroupProcessor (the responsibility of + implementing the aggregateMessages method is left to the + developer): + + public abstract class AbstractAggregatingMessageGroupProcessor + implements MessageGroupProcessor { + + protected Map<String, Object> aggregateHeaders(MessageGroup group) { + .... + } + + protected abstract Object aggregatePayloads(MessageGroup group); + +} + The CorrelationStrategy is owned by the CorrelatingMessageHandler and it has + a default value based on the correlation ID message header: + private volatile CorrelationStrategy correlationStrategy = + new HeaderAttributeCorrelationStrategy(MessageHeaders.CORRELATION_ID); + + When appropriate, the simplest option is the DefaultAggregatingMessageGroupProcessor. + It creates a single Message whose payload is a List of the payloads received + for a given group. It uses the default CorrelationStrategy and + CompletionStrategy as shown above. This works well for simple + Scatter Gather implementations with either a Splitter, Publish Subscribe Channel, + or Recipient List Router upstream. + + + When using a Publish Subscribe Channel or Recipient List Router in this + type of scenario, be sure to enable the flag to apply sequence. + That will add the necessary headers (correlation id, sequence number and sequence + size). That behavior is enabled by default for Splitters in Spring Integration, + but it is not enabled for the Publish Subscribe Channel or Recipient List + Router because those components may be used in a variety of contexts where + those headers are not necessary. + + + When implementing a specific aggregator object for an application, + a developer can extend AbstractAggregatingMessageGroupProcessor and + implement the aggregatePayloads method. However, there are + better suited (which reads, less coupled to the API) solutions for + implementing the aggregation logic, which can be configured easily + either through XML or through annotations. + + In general, any ordinary Java class (i.e. POJO) can implement the + aggregation algorithm. For doing so, it must provide a method that + accepts as an argument a single java.util.List (parametrized lists are + supported as well). This method will be invoked for aggregating + messages, as follows: + + + + if the argument is a parametrized java.util.List, and the + parameter type is assignable to Message, then the whole list of + messages accumulated for aggregation will be sent to the + aggregator + + + + if the argument is a non-parametrized java.util.List or the + parameter type is not assignable to Message, then the method will + receive the payloads of the accumulated messages + + + + if the return type is not assignable to Message, then it will + be treated as the payload for a Message that will be created + automatically by the framework. + + + + + In the interest of code simplicity, and promoting best practices + such as low coupling, testability, etc., the preferred way of + implementing the aggregation logic is through a POJO, and using the + XML or annotation support for setting it up in the application. + +
+ +
+ ReleaseStrategy + + The ReleaseStrategy interface is defined as + follows: + + public interface ReleaseStrategy { + + boolean canRelease(MessageGroup messages); + +} + + In general, any ordinary Java class (i.e. POJO) can implement the + completion decision mechanism. For doing so, it must provide a method + that accepts as an argument a single java.util.List (parametrized lists + are supported as well), and returns a boolean value. This method will be + invoked after the arrival of a new message, to decide whether the group + is complete or not, as follows: + + + + if the argument is a parametrized java.util.List, and the + parameter type is assignable to Message, then the whole list of + messages accumulated in the group will be sent to the method + + + + if the argument is a non-parametrized java.util.List or the + parameter type is not assignable to Message, then the method will + receive the payloads of the accumulated messages + + + + the method must return true if the message group is ready + for aggregation, and false otherwise. + + + + When the group is released for aggregation, all its + unmarked messages are processed and then marked so they will not + be processed again. If the group is also complete (i.e. if all + messages from a sequence have arrived or if there is no sequence + defined) then the group is removed from the message store. + Partial sequences can be released, in which case the next time + the ReleaseStrategy is called it will be presented + with a group containing marked messages (already processed) and + unmarked messages (a potential new partial sequence) + + Spring Integration provides an out-of-the box implementation for + ReleaseStrategy, the + SequenceSizerReleaseStrategy. This implementation uses + the SEQUENCE_NUMBER and SEQUENCE_SIZE of the arriving messages for + deciding when a message group is complete and ready to be + aggregated. As shown above, it is also the default strategy. +
+ +
+ CorrelationStrategy + + The CorrelationStrategy interface is defined as + follows: + + public interface CorrelationStrategy { + + Object getCorrelationKey(Message<?> message); + +} + + The method shall return an Object which represents the correlation + key used for grouping messages together. The key must satisfy the + criteria used for a key in a Map with respect to the implementation of + equals() and hashCode(). + + In general, any ordinary Java class (i.e. POJO) can implement the + correlation decision mechanism, and the rules for mapping a message to + a method's argument (or arguments) are the same as for a + ServiceActivator (including support for @Header + annotations). The method must return a value, and the value must not be + null. + + Spring Integration provides an out-of-the box implementation for + CorrelationStrategy, the + HeaderAttributeCorrelationStrategy. This implementation + returns the value of one of the message headers (whose name is specified + by a constructor argument) as the correlation key. By default, the + correlation strategy is a HeaderAttributeCorrelationStrategy returning + the value of the CORRELATION_ID header attribute. +
+
+ +
+ Configuring an Aggregator with XML + + Spring Integration supports the configuration of an aggregator via + XML through the <aggregator/> element. Below you can see an example of + an aggregator with all optional parameters defined. + + <channel id="inputChannel"/> + +<aggregator id="completelyDefinedAggregator" + input-channel="inputChannel" + output-channel="outputChannel" + discard-channel="discardChannel" + ref="aggregatorBean" + method="add" + release-strategy="releaseStrategyBean" + release-strategy-method="canRelease" + correlation-strategy="correlationStrategyBean" + correlation-strategy-method="groupNumbersByLastDigit" + message-store="messageStore" + send-partial-result-on-expiry="true" + send-timeout="86420000" /> + +<channel id="outputChannel"/> + +<bean id="aggregatorBean" class="sample.PojoAggregator"/> + +<bean id="releaseStrategyBean" class="sample.PojoReleaseStrategy"/> + +<bean id="correlationStrategyBean" class="sample.PojoCorrelationStrategy"/> + + + + The id of the aggregator is + optional. + + + + The input channel of the aggregator. + Required. + + + + The channel where the aggregator will send the aggregation + results. Optional (because incoming messages can specify a + reply channel themselves). + + + + The channel where the aggregator will send the messages that + timed out (if send-partial-results-on-timeout is + false). Optional. + + + + A reference to a bean defined in the application context. The + bean must implement the aggregation logic as described above. + Required. + + + + A method defined on the bean referenced by ref, + that implements the message aggregation + algorithm. Optional, with restrictions (see + above). + + + + A reference to a bean that implements the decision algorithm as + to whether a given message group is complete. The bean can be an + implementation of the CompletionStrategy interface or a POJO. In the + latter case the completion-strategy-method attribute must be defined + as well. Optional (by default, the aggregator will use + sequence size) . + + + + A method defined on the bean referenced by + release-strategy, that implements the + completion decision algorithm. Optional, with + restrictions (requires completion-strategy to be + present). + + + + A reference to a bean that implements the correlation strategy. + The bean can be an implementation of the CorrelationStrategy interface + or a POJO. In the latter case the correlation-strategy-method + attribute must be defined as well. Optional (by default, the + aggregator will use the correlation id header attribute) + . + + + + A method defined on the bean referenced by + correlation-strategy, that implements the + correlation key algorithm. Optional, with + restrictions (requires correlation-strategy to be + present). + + + + A reference to a MessageGroupStore that + can be used to store groups of messages under their + correlation key until they are + complete. Optional with default a + volatile in-memory store. + + + + Whether upon the expiration of the message group, the aggregator will + try to aggregate the messages that have already arrived. Optional + (false by default). + + + + The timeout for sending the aggregated messages to the + output or reply channel. Optional. + + + + Using a "ref" attribute is generally recommended if a custom aggregator handler + implementation can be reused in other <aggregator> definitions. + However if a custom aggregator handler implementation should be scoped to a concrete + definition of the <aggregator>, you can use an inner bean definition + (starting with version 1.0.3) for custom aggregator handlers within the + <aggregator> element: + + +]]> + + + + Using both a "ref" attribute and an inner bean definition in the same + <aggregator> configuration is not allowed, as it creates an + ambiguous condition. In such cases, an Exception will be thrown. + + + + An example implementation of the aggregator bean looks as follows: + + public class PojoAggregator { + + public Long add(List<Long> results) { + long total = 0l; + for (long partialResult: results) { + total += partialResult; + } + return total; + } + +} + + An implementation of the completion strategy bean for the example + above may be as follows: + + public class PojoReleaseStrategy { +... + public boolean canRelease(List<Long> numbers) { + int sum = 0; + for (long number: numbers) { + sum += number; + } + return sum >= maxValue; + } +} + + + Wherever it makes sense, the release strategy method and + the aggregator method can be combined in a single bean. + + + + An implementation of the correlation strategy bean for the example + above may be as follows: + + public class PojoCorrelationStrategy { +... + public Long groupNumbersByLastDigit(Long number) { + return number % 10; + } +} + + For example, this aggregator would group numbers by some criterion + (in our case the remainder after dividing by 10) and will hold the group + until the sum of the numbers which represents the payload exceeds a + certain value. + + + Wherever it makes sense, the release strategy method, correlation + strategy method and the aggregator method can be combined in a single bean + (all of them or any two). + +
+ +
+ Configuring an Aggregator with Annotations + + An aggregator configured using annotations can look like + this. + + public class Waiter { + ... + + @Aggregator + public Delivery aggregatingMethod(List<OrderItem> items) { + ... + } + + @ReleaseStrategy + public boolean releaseChecker(List<Message<?>> messages) { + ... + } + + @CorrelationStrategy + public String correlateBy(OrderItem item) { + ... + } + +} + + + + An annotation indicating that this method shall be used as an + aggregator. Must be specified if this class will be used as an + aggregator. + + + + An annotation indicating that this method shall be + used as the release strategy of an aggregator. If not present on + any method, the aggregator will use the + SequenceSizeCompletionStrategy. + + + + An annotation indicating that this method shall be + used as the correlation strategy of an aggregator. If no correlation + strategy is indicated, the aggregator will use the + HeaderAttributeCorrelationStrategy based on CORRELATION_ID. + + + + All of the configuration options provided by the xml element are also + available for the @Aggregator annotation. + + The aggregator can be either referenced explicitly from XML or, if + the @MessageEndpoint is defined on the class, detected automatically + through classpath scanning. + +
+ diff --git a/spring-integration-reference/src/bridge.xml b/spring-integration-reference/src/bridge.xml new file mode 100644 index 0000000000..bffeaa7fbf --- /dev/null +++ b/spring-integration-reference/src/bridge.xml @@ -0,0 +1,62 @@ + + + + Messaging Bridge + +
+ Introduction + + A Messaging Bridge is a relatively trivial endpoint that simply connects two Message Channels or Channel + Adapters. For example, you may want to connect a PollableChannel to a + SubscribableChannel so that the subscribing endpoints do not have to worry + about any polling configuration. Instead, the Messaging Bridge provides the polling configuration. + + + By providing an intermediary poller between two channels, a Messaging Bridge can be used to throttle inbound + Messages. The poller's trigger will determine the rate at which messages arrive on the second channel, and the + poller's "maxMessagesPerPoll" property will enforce a limit on the throughput. + + + Another valid use for a Messaging Bridge is to connect two different systems. In such a scenario, Spring + Integration's role would be limited to making the connection between these systems and managing a poller + if necessary. It is probably more common to have at least a Transformer between the + two systems to translate between their formats, and in that case, the channels would be provided as the + 'input-channel' and 'output-channel' of a Transformer endpoint. If data format translation is not required, + the Messaging Bridge may indeed be sufficient. + +
+ +
+ The <bridge> Element + + The <bridge> element is used to create a Messaging Bridge between two Message Channels or Channel Adapters. + Simply provide the "input-channel" and "output-channel" attributes: + ]]> + As mentioned above, a common use case for the Messaging Bridge is to connect a + PollableChannel to a SubscribableChannel, and when + performing this role, the Messaging Bridge may also serve as a throttler: + + + + + ]]> + + + Connecting Channel Adapters is just as easy. Here is a simple echo example between the "stdin" and "stdout" + adapters from Spring Integration's "stream" namespace. + + + + + ]]> + Of course, the configuration would be similar for other (potentially more useful) Channel Adapter bridges, such + as File to JMS, or Mail to File. The various Channel Adapters will be discussed in upcoming chapters. + + + If no 'output-channel' is defined on a bridge, the reply channel provided by the inbound Message will + be used, if available. If neither output or reply channel is available, an Exception will be thrown. + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/chain.xml b/spring-integration-reference/src/chain.xml new file mode 100644 index 0000000000..2564a9c7e0 --- /dev/null +++ b/spring-integration-reference/src/chain.xml @@ -0,0 +1,115 @@ + + + + Message Handler Chain + +
+ Introduction + + The MessageHandlerChain is an implementation of + MessageHandler that can be configured as a single Message Endpoint while + actually delegating to a chain of other handlers, such as Filters, Transformers, Splitters, and so on. + This can lead to a much simpler configuration when several handlers need to be connected in a fixed, linear + progression. For example, it is fairly common to provide a Transformer before other components. Similarly, when + providing a Filter before some other component in a chain, you are essentially creating a + Selective Consumer. In either case, the + chain only requires a single input-channel and a single output-channel as opposed to the configuration of + channels for each individual component. + + Spring Integration's Filter provides a boolean property 'throwExceptionOnRejection'. When + providing multiple Selective Consumers on the same point-to-point channel with different acceptance criteria, + this value should be set to 'true' (the default is false) so that the dispatcher will know that the Message was + rejected and as a result will attempt to pass the Message on to other subscribers. If the Exception were not + thrown, then it would appear to the dispatcher as if the Message had been passed on successfully even though + the Filter had dropped the Message to prevent further processing. + + + + The handler chain simplifies configuration while internally maintaining the same degree of loose coupling between + components, and it is trivial to modify the configuration if at some point a non-linear arrangement is required. + + + Internally, the chain will be expanded into a linear setup of the listed endpoints, separated by direct channels. + The reply channel header will not be taken into account within the chain: only after the last handler is invoked + will the resulting message be forwarded on to the reply channel or the chain's output channel. Because of this + setup all handlers except the last require a setOutputChannel implementation. The last + handler only needs an output channel if the outputChannel on the MessageHandlerChain is set. + + + As with other endpoints, the output-channel is optional. If there is a reply Message at the end of the + chain, the output-channel takes precedence, but if not available, the chain handler will check for a + reply channel header on the inbound Message. + + + + + In most cases there is no need to implement MessageHandlers yourself. The next section will focus on namespace + support for the chain element. Most Spring Integration endpoints, like Service Activators and Transformers, are + suitable for use within a MessageHandlerChain. + +
+ +
+ The <chain> Element + + The <chain> element provides an 'input-channel' attribute, and if the last element in the chain is capable + of producing reply messages (optional), it also supports an 'output-channel' attribute. The sub-elements are then + filters, transformers, splitters, and service-activators. The last element may also be a router. + + + +
+ + + ]]> + + + The <header-enricher> element used in the above example will set a message header with name "foo" and + value "bar" on the message. A header enricher is a specialization of Transformer that touches only header + values. You could obtain the same result by implementing a MessageHandler that did the header modifications + and wiring that as a bean. + + + + Some time you need to make a nested call to another chain from within the chain and then come + back and continue execution within the original chain. + To accomplish this you can utilize Messaging Gateway by including light-configuration via <gateway> element. + For example: + + + + + + + +   + + + + + +   + + + + + + + + + + + + ]]> + +In the above example the nested-chain-a will be called at the end of main-chain processing by the 'gateway' element +configured there. While in nested-chain-a a call to a nested-chain-b will be made after header enrichment and then it will +come back to finish execution in nested-chain-b finally getting back to the main-chain. +When light version of <gateway> element is defined in the chain SI will construct an instance SimpleMessagingGateway + (no need to provide 'service-interface' configuration) which will take the message in its current state and will place it on the channel defined via 'request-channel' attribute. + Upon processing Message will be returned to the gateway and continue its journey within the current chain. + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/channel-adapter.xml b/spring-integration-reference/src/channel-adapter.xml new file mode 100644 index 0000000000..78bcd042c1 --- /dev/null +++ b/spring-integration-reference/src/channel-adapter.xml @@ -0,0 +1,83 @@ + + + + Channel Adapter + + A Channel Adapter is a Message Endpoint that enables connecting a single sender or receiver to a Message Channel. + Spring Integration provides a number of adapters out of the box to support various transports, such as JMS, File, + HTTP, Web Services, and Mail. Those will be discussed in upcoming chapters of this reference guide. However, this + chapter focuses on the simple but flexible Method-invoking Channel Adapter support. There are both inbound and + outbound adapters, and each may be configured with XML elements provided in the core namespace. + + +
+ The <inbound-channel-adapter> element + + An "inbound-channel-adapter" element can invoke any method on a Spring-managed Object and send a non-null return + value to a MessageChannel after converting it to a Message. + When the adapter's subscription is activated, a poller will attempt to receive messages from the source. The + poller will be scheduled with the TaskScheduler according to the provided + configuration. To configure the polling interval or cron expression for an individual channel-adapter, + provide a 'poller' element with either an 'interval-trigger' (in milliseconds) or 'cron-trigger' + sub-element. + + + + + + + + + + +]]> + + + + If no poller is provided, then a single default poller must be registered within the context. + See for more detail. + + +
+ +
+ The <outbound-channel-adapter/> element + + An "outbound-channel-adapter" element can also connect a MessageChannel to any POJO consumer + method that should be invoked with the payload of Messages sent to that channel. + ]]> + If the channel being adapted is a PollableChannel, provide a poller sub-element: + + ]]> + + ]]> + +]]> + + + Using a "ref" attribute is generally recommended if the POJO consumer implementation can be reused + in other <outbound-channel-adapter> definitions. However if the consumer implementation + should be scoped to a single definition of the <outbound-channel-adapter>, you can define it as inner bean: + + + ]]> +]]> + + + + Using both the "ref" attribute and an inner handler definition in the same <outbound-channel-adapter> + configuration is not allowed, as it creates an ambiguous condition and will result in an Exception being thrown. + + + + Any Channel Adapter can be created without a "channel" reference in which case it will implicitly create an + instance of DirectChannel. The created channel's name will match the "id" attribute + of the <inbound-channel-adapter/> or <outbound-channel-adapter>l; element. Therefore, if the "channel" + is not provided, the "id" is required. + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/channel.xml b/spring-integration-reference/src/channel.xml new file mode 100644 index 0000000000..0e46803ab7 --- /dev/null +++ b/spring-integration-reference/src/channel.xml @@ -0,0 +1,595 @@ + + + + Message Channels + + While the Message plays the crucial role of encapsulating data, it is the + MessageChannel that decouples message producers from message consumers. + + +
+ The MessageChannel Interface + + Spring Integration's top-level MessageChannel interface is defined as follows. + + When sending a message, the return value will be true if the message is sent successfully. + If the send call times out or is interrupted, then it will return false. + + +
+ PollableChannel + + Since Message Channels may or may not buffer Messages (as discussed in the overview), there are two + sub-interfaces defining the buffering (pollable) and non-buffering (subscribable) channel behavior. Here is the + definition of PollableChannel. + public interface PollableChannel extends MessageChannel { + + Message<?> receive(); + + Message<?> receive(long timeout); + + List<Message<?>> clear(); + + List<Message<?>> purge(MessageSelector selector); + +} + Similar to the send methods, when receiving a message, the return value will be null in the + case of a timeout or interrupt. + +
+ +
+ SubscribableChannel + + The SubscribableChannel base interface is implemented by channels that send + Messages directly to their subscribed MessageHandlers. Therefore, they do not + provide receive methods for polling, but instead define methods for managing those subscribers: + public interface SubscribableChannel extends MessageChannel { + + boolean subscribe(MessageHandler handler); + + boolean unsubscribe(MessageHandler handler); + +} + +
+
+ +
+ Message Channel Implementations + + Spring Integration provides several different Message Channel implementations. Each is briefly described in the + sections below. + +
+ PublishSubscribeChannel + + The PublishSubscribeChannel implementation broadcasts any Message + sent to it to all of its subscribed handlers. This is most often used for sending + Event Messages whose primary role is notification as opposed to + Document Messages which are generally intended to be processed by + a single handler. Note that the PublishSubscribeChannel is + intended for sending only. Since it broadcasts to its subscribers directly when its + send(Message) method is invoked, consumers cannot poll for + Messages (it does not implement PollableChannel and + therefore has no receive() method). Instead, any subscriber + must be a MessageHandler itself, and the subscriber's + handleMessage(Message) method will be invoked in turn. + +
+
+ QueueChannel + + The QueueChannel implementation wraps a queue. Unlike the + PublishSubscribeChannel, the QueueChannel has point-to-point + semantics. In other words, even if the channel has multiple consumers, only one of them should receive any + Message sent to that channel. It provides a default no-argument constructor (providing an essentially unbounded + capacity of Integer.MAX_VALUE) as well as a constructor that accepts the queue capacity: + public QueueChannel(int capacity) + A channel that has not reached its capacity limit will store messages in its internal queue, and the + send() method will return immediately even if no receiver is ready to handle the + message. If the queue has reached capacity, then the sender will block until room is available. Or, if using + the send call that accepts a timeout, it will block until either room is available or the timeout period + elapses, whichever occurs first. Likewise, a receive call will return immediately if a message is available + on the queue, but if the queue is empty, then a receive call may block until either a message is available + or the timeout elapses. In either case, it is possible to force an immediate return regardless of the + queue's state by passing a timeout value of 0. Note however, that calls to the no-arg versions of + send() and receive() will block indefinitely. + +
+
+ PriorityChannel + + Whereas the QueueChannel enforces first-in/first-out (FIFO) ordering, the + PriorityChannel is an alternative implementation that allows for messages + to be ordered within the channel based upon a priority. By default the priority is determined by the + 'priority' header within each message. However, for custom priority determination + logic, a comparator of type Comparator<Message<?>> can be provided + to the PriorityChannel's constructor. + +
+
+ RendezvousChannel + + The RendezvousChannel enables a "direct-handoff" scenario where a sender will block + until another party invokes the channel's receive() method or vice-versa. Internally, + this implementation is quite similar to the QueueChannel except that it uses a + SynchronousQueue (a zero-capacity implementation of + BlockingQueue). This works well in situations where the sender and receiver are + operating in different threads but simply dropping the message in a queue asynchronously is not appropriate. + In other words, with a RendezvousChannel at least the sender knows that some receiver + has accepted the message, whereas with a QueueChannel, the message would have been + stored to the internal queue and potentially never received. + + + + Keep in mind that all of these queue-based channels are storing messages in-memory only. When persistence + is required, you can either invoke a database operation within a handler or use Spring Integration's + support for JMS-based Channel Adapters. The latter option allows you to take advantage of any JMS provider's + implementation for message persistence, and it will be discussed in . However, when + buffering in a queue is not necessary, the simplest approach is to rely upon the + DirectChannel discussed next. + + + + The RendezvousChannel is also useful for implementing request-reply + operations. The sender can create a temporary, anonymous instance of RendezvousChannel + which it then sets as the 'replyChannel' header when building a Message. After sending that Message, the sender + can immediately call receive (optionally providing a timeout value) in order to block while waiting for a reply + Message. This is very similar to the implementation used internally by many of Spring Integration's + request-reply components. + +
+
+ DirectChannel + + The DirectChannel has point-to-point semantics but otherwise is more similar to the + PublishSubscribeChannel than any of the queue-based channel implementations described + above. It implements the SubscribableChannel interface instead of the + PollableChannel interface, so it dispatches Messages directly to a subscriber. + As a point-to-point channel, however, it differs from the PublishSubscribeChannel in + that it will only send each Message to a single subscribed + MessageHandler. + + + In addition to being the simplest point-to-point channel option, one of its most important features is that + it enables a single thread to perform the operations on "both sides" of the channel. For example, if a handler + is subscribed to a DirectChannel, then sending a Message to that channel will trigger + invocation of that handler's handleMessage(Message) method directly in the + sender's thread, before the send() method invocation can return. + + + The key motivation for providing a channel implementation with this behavior is to support transactions that + must span across the channel while still benefiting from the abstraction and loose coupling that the channel + provides. If the send call is invoked within the scope of a transaction, then the outcome of the handler's + invocation (e.g. updating a database record) will play a role in determining the ultimate result of that + transaction (commit or rollback). + + Since the DirectChannel is the simplest option and does not add any additional + overhead that would be required for scheduling and managing the threads of a poller, it is the default + channel type within Spring Integration. The general idea is to define the channels for an application and + then to consider which of those need to provide buffering or to throttle input, and then modify those to + be queue-based PollableChannels. Likewise, if a channel needs to broadcast + messages, it should not be a DirectChannel but rather a + PublishSubscribeChannel. Below you will see how each of these can be configured. + + + + The DirectChannel internally delegates to a Message Dispatcher to invoke its + subscribed Message Handlers, and that dispatcher can have a load-balancing strategy. The load-balancer + determines how invocations will be ordered in the case that there are multiple handlers subscribed to the + same channel. When using the namespace support described below, the default strategy is + "round-robin" which essentially load-balances across the handlers in rotation. + + The "round-robin" strategy is currently the only implementation available out-of-the-box in Spring + Integration. Other strategy implementations may be added in future versions. + + + + The load-balancer also works in combination with a boolean failover property. + If the "failover" value is true (the default), then the dispatcher will fall back to any subsequent + handlers as necessary when preceding handlers throw Exceptions. The order is determined by an optional + order value defined on the handlers themselves or, if no such value exists, the order in which the + handlers are subscribed. + + + If a certain situation requires that the dispatcher always try to invoke the first handler, then + fallback in the same fixed order sequence every time an error occurs, no load-balancing strategy should + be provided. In other words, the dispatcher still supports the failover boolean property even when no + load-balancing is enabled. Without load-balancing, however, the invocation of handlers will always begin + with the first according to their order. For example, this approach works well when there is a clear + definition of primary, secondary, tertiary, and so on. When using the namespace support, the "order" + attribute on any endpoint will determine that order. + + + Keep in mind that load-balancing and failover only apply when a channel has more than one + subscribed Message Handler. When using the namespace support, this means that more than one + endpoint shares the same channel reference in the "input-channel" attribute. + +
+
+ ExecutorChannel + + The ExecutorChannel is a point-to-point channel that supports + the same dispatcher configuration as DirectChannel (load-balancing strategy + and the failover boolean property). The key difference between these two dispatching channel types + is that the ExecutorChannel delegates to an instance of + TaskExecutor to perform the dispatch. This means that the send method + typically will not block, but it also means that the handler invocation may not occur in the sender's + thread. It therefore does not support transactions spanning the sender and receiving + handler. + + Note that there are occasions where the sender may block. For example, when using a + TaskExecutor with a rejection-policy that throttles back on the client (such as the + ThreadPoolExecutor.CallerRunsPolicy), the sender's thread will execute + the method directly anytime the thread pool is at its maximum capacity and the + executor's work queue is full. Since that situation would only occur in a non-predictable + way, that obviously cannot be relied upon for transactions. + + +
+
+ ThreadLocalChannel + + The final channel implementation type is ThreadLocalChannel. This channel also delegates + to a queue internally, but the queue is bound to the current thread. That way the thread that sends to the + channel will later be able to receive those same Messages, but no other thread would be able to access them. + While probably the least common type of channel, this is useful for situations where + DirectChannels are being used to enforce a single thread of operation but any reply + Messages should be sent to a "terminal" channel. If that terminal channel is a + ThreadLocalChannel, the original sending thread can collect its replies from it. + +
+
+ +
+ Channel Interceptors + + One of the advantages of a messaging architecture is the ability to provide common behavior and capture + meaningful information about the messages passing through the system in a non-invasive way. Since the + Messages are being sent to and received from + MessageChannels, those channels provide an opportunity for intercepting + the send and receive operations. The ChannelInterceptor strategy interface + provides methods for each of those operations: + preSend(Message message, MessageChannel channel); + + void postSend(Message message, MessageChannel channel, boolean sent); + + boolean preReceive(MessageChannel channel); + + Message postReceive(Message message, MessageChannel channel); +}]]> + After implementing the interface, registering the interceptor with a channel is just a matter of calling: + channel.addInterceptor(someChannelInterceptor); + The methods that return a Message instance can be used for transforming the Message or can return 'null' + to prevent further processing (of course, any of the methods can throw a RuntimeException). Also, the + preReceive method can return 'false' to prevent the receive + operation from proceeding. + + Keep in mind that receive() calls are only relevant for + PollableChannels. In fact the + SubscribableChannel interface does not even define a + receive() method. The reason for this is that when a Message is sent to a + SubscribableChannel it will be sent directly to one or more subscribers + depending on the type of channel (e.g. a PublishSubscribeChannel sends to all of its subscribers). Therefore, + the preReceive(..) and postReceive(..) interceptor methods + are only invoked when the interceptor is applied to a PollableChannel. + + Spring Integration also provides an implementation of the + Wire Tap pattern. + It is a simple interceptor that sends the Message to another channel without otherwise altering the + existing flow. It can be very useful for debugging and monitoring. An example is shown in + . + + + Because it is rarely necessary to implement all of the interceptor methods, a + ChannelInterceptorAdapter class is also available for sub-classing. It provides no-op + methods (the void method is empty, the Message returning methods + return the Message as-is, and the boolean method returns true). + Therefore, it is often easiest to extend that class and just implement the method(s) that you need as in the + following example. + preSend(Message message, MessageChannel channel) { + sendCount.incrementAndGet(); + return message; + } +}]]> + + The order of invocation for the interceptor methods depends on the type of channel. As described above, + the queue-based channels are the only ones where the receive method is intercepted in the first place. + Additionally, the relationship between send and receive interception depends on the timing of separate + sender and receiver threads. For example, if a receiver is already blocked while waiting for a message + the order could be: preSend, preReceive, postReceive, postSend. However, if a receiver polls after the + sender has placed a message on the channel and already returned, the order would be: preSend, postSend, + (some-time-elapses) preReceive, postReceive. The time that elapses in such a case depends on a number + of factors and is therefore generally unpredictable (in fact, the receive may never happen!). + Obviously, the type of queue also plays a role (e.g. rendezvous vs. priority). The bottom line is that + you cannot rely on the order beyond the fact that preSend will precede postSend and preReceive will + precede postReceive. + + +
+ +
+ MessageChannelTemplate + + As you will see when the endpoints and their various configuration options are introduced, Spring Integration + provides a foundation for messaging components that enables non-invasive invocation of your application code + from the messaging system. However, sometimes it is necessary to invoke the messaging system + from your application code. For convenience when implementing such use-cases, Spring + Integration provides a MessageChannelTemplate that supports a variety of operations across + the Message Channels, including request/reply scenarios. For example, it is possible to send a request + and wait for a reply. + MessageChannelTemplate template = new MessageChannelTemplate(); + +Message reply = template.sendAndReceive(new StringMessage("test"), someChannel); + In that example, a temporary anonymous channel would be created internally by the template. The + 'sendTimeout' and 'receiveTimeout' properties may also be set on the template, and other exchange + types are also supported. + message, final MessageChannel channel) { ... } + +public Message sendAndReceive(final Message request, final MessageChannel channel) { .. } + +public Message receive(final PollableChannel channel) { ... }]]> + + + + A less invasive approach that allows you to invoke simple interfaces with payload and/or header + values instead of Message instances is described in . + + +
+ +
+ Configuring Message Channels + + To create a Message Channel instance, you can use the 'channel' element: + <channel id="exampleChannel"/> + + + The default channel type is Point to Point. To create a + Publish Subscribe channel, use the "publish-subscribe-channel" element: + <publish-subscribe-channel id="exampleChannel"/> + + + To create a Datatype Channel that only + accepts messages containing a certain payload type, provide the fully-qualified class name in the + channel element's datatype attribute: + ]]> + Note that the type check passes for any type that is assignable to the channel's + datatype. In other words, the "numberChannel" above would accept messages whose payload is + java.lang.Integer or java.lang.Double. Multiple types can be + provided as a comma-delimited list: + ]]> + + + When using the "channel" element without any sub-elements, it will create a DirectChannel + instance (a SubscribableChannel). + + + However, you can alternatively provide a variety of "queue" sub-elements to create any of + the pollable channel types (as described in + ). Examples of each are shown below. + +
+ DirectChannel Configuration + + As mentioned above, DirectChannel is the default type. + ]]> + + + A default channel will have a round-robin load-balancer and will also have + failover enabled (See the discussion in + for more detail). To disable one or both of these, add a <dispatcher/> sub-element and + configure the attributes: + + + + + + + +]]> + +
+
+ QueueChannel Configuration + + To create a QueueChannel, use the "queue" sub-element. + You may specify the channel's capacity: + <channel id="queueChannel"> + <queue capacity="25"/> +</channel> + + If you do not provide a value for the 'capacity' attribute on this <queue/> sub-element, + the resulting queue will be unbounded. To avoid issues such as OutOfMemoryErrors, it is highly + recommended to set an explicit value for a bounded queue. + + +
+
+ PublishSubscribeChannel Configuration + + To create a PublishSubscribeChannel, use the "publish-subscribe-channel" element. + When using this element, you can also specify the "task-executor" used for publishing + Messages (if none is specified it simply publishes in the sender's thread): + <publish-subscribe-channel id="pubsubChannel" task-executor="someExecutor"/> + If you are providing a Resequencer or Aggregator downstream + from a PublishSubscribeChannel, then you can set the 'apply-sequence' property + on the channel to true. That will indicate that the channel should set the sequence-size + and sequence-number Message headers as well as the correlation id prior to passing the Messages along. + For example, if there are 5 subscribers, the sequence-size would be set to 5, and the Messages would + have sequence-number header values ranging from 1 to 5. + <publish-subscribe-channel id="pubsubChannel" apply-sequence="true"/> + + The 'apply-sequence' value is false by default so that a Publish Subscribe Channel + can send the exact same Message instances to multiple outbound channels. Since Spring Integration + enforces immutability of the payload and header references, the channel creates new Message + instances with the same payload reference but different header values when the flag is set to + true. + + +
+
+ ExecutorChannel + + To create an ExecutorChannel, add the <dispatcher> sub-element along + with a 'task-executor' attribute. Its value can reference any TaskExecutor + within the context. For example, this enables configuration of a thread-pool for dispatching messages + to subscribed handlers. As mentioned above, this does break the "single-threaded" execution context + between sender and receiver so that any active transaction context will not be shared by the invocation + of the handler (i.e. the handler may throw an Exception, but the send invocation has already returned + successfully). + + +]]> + + + The "load-balancer" and "failover" options are also both available on the dispatcher sub-element + as described above in . The same defaults + apply as well. So, the channel will have a round-robin load-balancing strategy with failover + enabled unless explicit configuration is provided for one or both of those attributes. + + +]]> + +
+
+ PriorityChannel Configuration + + To create a PriorityChannel, use the "priority-queue" sub-element: + + +]]> + By default, the channel will consult the MessagePriority header of the + message. However, a custom Comparator reference may be + provided instead. Also, note that the PriorityChannel (like the other types) + does support the "datatype" attribute. As with the QueueChannel, it also supports a "capacity" attribute. + The following example demonstrates all of these: + + + +]]> + +
+
+ RendezvousChannel Configuration + + A RendezvousChannel is created when the queue sub-element is + a <rendezvous-queue>. It does not provide any additional configuration options to + those described above, and its queue does not accept any capacity value since it is a + 0-capacity direct handoff queue. + + + +]]> + +
+
+ ThreadLocalChannel Configuration + + The ThreadLocalChannel does not provide any additional configuration options. + ]]> + +
+ +
+ Channel Interceptor Configuration + + Message channels may also have interceptors as described in . The + <interceptors> sub-element can be added within <channel> (or the more specific element + types). Provide the "ref" attribute to reference any Spring-managed object that implements the + ChannelInterceptor interface: + + ]]> + + ]]>]]> + In general, it is a good idea to define the interceptor implementations in a separate location since they + usually provide common behavior that can be reused across multiple channels. + +
+ +
+ Global Channel Interceptor Configuration + + Channel Interceptors allow you for a clean and concise way of applying cross-cutting behavior per individual channel. + But what if the same behavior should be applied on multiple channels, configuring the same set of interceptors for + each channel would not be the most efficient way. The better way would be to configure interceptors globally and apply + them on multiple channels in one shot. Spring Integration provides capabilities to configure Global Interceptor Chains + and apply them on multiple channels. + Look at the example below: + + + +]]> + <channel-interceptor-chain> element will assemble the chain of interceptors and will apply them on all the + channels defined in the <channel-name-patter> attribute. In the above case the two interceptors that are defined + within the chain are going to be applied on 'foo' channel and all other channels that begin with 'bar' and 'input'. + The <order> attribute allows you to manage the place where this interceptor chain will be injected. + For example, channel 'inputChannel' could have individual interceptors configured locally (see below): +   + +   + +]]> + The reasonable question would be where interceptors defined by channel-interceptor-cahin should be injected + in relation to the existing one(s) (configured locally or through other global chains)? Current implementation provides + a very simple and clever mechanism of handling this. Positive number in the order attribute will ensure interceptor injection + after existing interceptors and negative number will ensure that such interceptors injected before. + This means that in the above example interceptors configured in global interceptor chain would be injected after + 'wire-tap' interceptor configured locally. If there was another global chain with matching channel-name-pattern the + order between the interceptors defined in two chains would be determined based on who's got the higher or lower + value in order attribute. + +
+ +
+ Wire Tap + + As mentioned above, Spring Integration provides a simple Wire Tap interceptor out of + the box. You can configure a Wire Tap on any channel within an 'interceptors' element. + This is especially useful for debugging, and can be used in conjunction with Spring Integration's logging + Channel Adapter as follows: + + + + + + ]]> + + The 'logging-channel-adapter' also accepts a boolean attribute: 'log-full-message'. + That is false by default so that only the payload is logged. Setting that to + true enables logging of all headers in addition to the payload. + + +
+ + + + If namespace support is enabled, there are also two special channels defined within the context by default: + errorChannel and nullChannel. The 'nullChannel' acts like /dev/null, + simply logging any Message sent to it at DEBUG level and returning immediately. Any time you face channel + resolution errors for a reply that you don't care about, you can set the affected component's 'output-channel' + to reference 'nullChannel' (the name 'nullChannel' is reserved within the context). The 'errorChannel' is + used internally for sending error messages, and it can be overridden with a custom configuration. It is + discussed in greater detail in . + + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/configuration.xml b/spring-integration-reference/src/configuration.xml new file mode 100644 index 0000000000..e6885b3e8d --- /dev/null +++ b/spring-integration-reference/src/configuration.xml @@ -0,0 +1,502 @@ + + + + Configuration +
+ Introduction + + Spring Integration offers a number of configuration options. Which option you choose depends upon your particular + needs and at what level you prefer to work. As with the Spring framework in general, it is also possible to mix + and match the various techniques according to the particular problem at hand. For example, you may choose the + XSD-based namespace for the majority of configuration combined with a handful of objects that are configured with + annotations. As much as possible, the two provide consistent naming. XML elements defined by the XSD schema will + match the names of annotations, and the attributes of those XML elements will match the names of annotation + properties. Direct usage of the API is of course always an option, but we expect that most users will choose one + of the higher-level options, or a combination of the namespace-based and annotation-driven configuration. + +
+ +
+ Namespace Support + + Spring Integration components can be configured with XML elements that map directly to the terminology and + concepts of enterprise integration. In many cases, the element names match those of the + Enterprise Integration Patterns. + + + To enable Spring Integration's core namespace support within your Spring configuration files, add the following + namespace reference and schema mapping in your top-level 'beans' element: + xmlns:integration="http://www.springframework.org/schema/integration"http://www.springframework.org/schema/integration + http://www.springframework.org/schema/integration/spring-integration-1.0.xsd"> + + + You can choose any name after "xmlns:"; integration is used here for clarity, but you might + prefer a shorter abbreviation. Of course if you are using an XML-editor or IDE support, then the availability of + auto-completion may convince you to keep the longer name for clarity. Alternatively, you can create configuration + files that use the Spring Integration schema as the primary namespace: + <beans:beans xmlns="http://www.springframework.org/schema/integration"xmlns:beans="http://www.springframework.org/schema/beans"]]> + + + When using this alternative, no prefix is necessary for the Spring Integration elements. On the other hand, if + you want to define a generic Spring "bean" within the same configuration file, then a prefix would be required + for the bean element (<beans:bean ... />). Since it is generally a good idea to modularize the + configuration files themselves based on responsibility and/or architectural layer, you may find it appropriate to + use the latter approach in the integration-focused configuration files, since generic beans are seldom necessary + within those same files. For purposes of this documentation, we will assume the "integration" namespace is + primary. + + + Many other namespaces are provided within the Spring Integration distribution. In fact, each adapter type (JMS, + File, etc.) that provides namespace support defines its elements within a separate schema. In order to use these + elements, simply add the necessary namespaces with an "xmlns" entry and the corresponding "schemaLocation" mapping. + For example, the following root element shows several of these namespace declarations: + + + ... +]]> + The reference manual provides specific examples of the various elements in their corresponding chapters. Here, the + main thing to recognize is the consistency of the naming for each namespace URI and schema location. + +
+ +
+ Configuring the Task Scheduler + + In Spring Integration, the ApplicationContext plays the central role of a Message Bus, and there are only a + couple configuration options to be aware of. First, you may want to control the central TaskScheduler instance. + You can do so by providing a single bean with the name "taskScheduler". This is also defined as a constant: + + By default Spring Integration uses the SimpleTaskScheduler implementation. That in turn + just delegates to any instance of Spring's TaskExecutor abstraction. Therefore, + it's rather trivial to supply your own configuration. The "taskScheduler" bean is then responsible for managing + all pollers. The TaskScheduler will startup automatically by default. If you provide your own instance of + SimpleTaskScheduler however, you can set the 'autoStartup' property to false instead. + + + When Polling Consumers provide an explicit task-executor reference in their configuration, the invocation of + the handler methods will happen within that executor's thread pool and not the main scheduler pool. However, + when no task-executor is provided for an endpoint's poller, it will be invoked by one of the main scheduler's + threads. + + An endpoint is a Polling Consumer if its input channel is one of the queue-based + (i.e. pollable) channels. On the other hand, Event Driven Consumers are those whose + input channels have dispatchers instead of queues (i.e. they are subscribable). Such endpoints have no + poller configuration since their handlers will be invoked directly. + + + The next section will describe what happens if Exceptions occur within the asynchronous invocations. + + +
+ +
+ Error Handling + + As described in the overview at the very beginning of this manual, one of the main motivations behind a + Message-oriented framework like Spring Integration is to promote loose-coupling between components. The + Message Channel plays an important role in that producers and consumers do not have to know about each + other. However, the advantages also have some drawbacks. Some things become more complicated in a very + loosely coupled environment, and one example is error handling. + + + When sending a Message to a channel, the component that ultimately handles that Message may or may not + be operating within the same thread as the sender. If using a simple default DirectChannel (with the + <channel> element that has no <queue> sub-element and no 'task-executor' attribute), the + Message-handling will occur in the same thread as the Message-sending. In that case, if an Exception + is thrown, it can be caught by the sender (or it may propagate past the sender if it is an uncaught + RuntimeException). So far, everything is fine. This is the same behavior as an Exception-throwing + operation in a normal call stack. However, when adding the asynchronous aspect, things become much + more complicated. For instance, if the 'channel' element does provide a 'queue' + sub-element, then the component that handles the Message will be operating in a + different thread than the sender. The sender may have dropped the Message into the channel and moved + on to other things. There is no way for the Exception to be thrown directly back to that sender using + standard Exception throwing techniques. Instead, to handle errors for asynchronous processes requires + an asynchronous error-handling mechanism as well. + + + Spring Integration supports error handling for its components by publishing errors to a Message Channel. + Specifically, the Exception will become the payload of a Spring Integration Message. That Message will + then be sent to a Message Channel that is resolved in a way that is similar to the 'replyChannel' + resolution. First, if the request Message being handled at the time the Exception occurred contains + an 'errorChannel' header (the header name is defined in the constant: MessageHeaders.ERROR_CHANNEL), + the ErrorMessage will be sent to that channel. Otherwise, the error handler will send to a "global" + channel whose bean name is "errorChannel" (this is also defined as a constant: + IntegrationContextUtils.ERROR_CHANNEL_BEAN_NAME). + + + Whenever relying on Spring Integration's XML namespace support, a default "errorChannel" bean will be + created behind the scenes. However, you can just as easily define your own if you want to control the + settings. + + + ]]> + + The default "errorChannel" is a PublishSubscribeChannel. + + + + The most important thing to understand here is that the messaging-based error handling will only apply + to Exceptions that are thrown by a Spring Integration task that is executing within a TaskExecutor. + This does not apply to Exceptions thrown by a handler that is operating within + the same thread as the sender (e.g. through a DirectChannel as described above). + + + When Exceptions occur in a scheduled poller task's execution, those exceptions will be wrapped in + ErrorMessages and sent to the 'errorChannel' as well. + + + To enable global error handling, simply register a handler on that channel. For example, you can configure + Spring Integration's ErrorMessageExceptionTypeRouter as the handler of an endpoint + that is subscribed to the 'errorChannel'. That router can then spread the error messages across multiple + channels based on Exception type. + +
+ +
+ Annotation Support + + In addition to the XML namespace support for configuring Message Endpoints, it is also possible to use + annotations. First, Spring Integration provides the class-level @MessageEndpoint + as a stereotype annotation meaning that is itself annotated with Spring's @Component + annotation and therefore is recognized automatically as a bean definition when using Spring component-scanning. + + + Even more importantly are the various Method-level annotations that indicate the annotated method is capable of + handling a message. The following example demonstrates both: + @MessageEndpoint +public class FooService { + + @ServiceActivator + public void processMessage(Message message) { + ... + } +} + + + Exactly what it means for the method to "handle" the Message depends on the particular annotation. The following + are available with Spring Integration, and the behavior of each is described in its own chapter or section within + this reference: @Transformer, @Router, @Splitter, @Aggregator, @ServiceActivator, and @ChannelAdapter. + + + The @MessageEndpoint is not required if using XML configuration in combination with annotations. If you want to + configure a POJO reference from the "ref" attribute of a <service-activator/> element, it is sufficient to + provide the method-level annotations. In that case, the annotation prevents ambiguity even when no "method" + attribute exists on the <service-activator/> element. + + + In most cases, the annotated handler method should not require the Message type as its + parameter. Instead, the method parameter type can match the message's payload type. + public class FooService { + + @ServiceActivator + public void bar(Foo foo) { + ... + } + +} + + + When the method parameter should be mapped from a value in the MessageHeaders, another + option is to use the parameter-level @Header annotation. In general, methods + annotated with the Spring Integration annotations can either accept the Message itself, the + message payload, or a header value (with @Header) as the parameter. In fact, the method can accept a combination, + such as: + public class FooService { + + @ServiceActivator + public void bar(String payload, @Header("x") int valueX, @Header("y") int valueY) { + ... + } + +} + There is also a @Headers annotation that provides all of the Message headers as a Map: + public class FooService { + + @ServiceActivator + public void bar(String payload, @Headers Map<String, Object> headerMap) { + ... + } + +} + +A more powerful and flexible way to map Messages to method arguments is to use @MessageMapping +annotation which allows you to define expression via Spring 3.0 Expression Language support to help parse +the message payload and/or header and map the parsed values to method arguments. + +For example: + +public void fromMessageToMethod(@MessageMapping("headers.day") String argA, + @MessageMapping("#this") Message message, + @MessageMapping("payload") Employee payloadArg, + @MessageMapping("payload.fname") String value, + @MessageMapping("headers") Map headers) { ... } + +As you can see, the above method takes 5 arguments where: + + + First - will be mapped to the value of 'day' header + + + Second - will be mapped to the Message itself + + + Third - will be mapped to the Payload + + + Fourth - will be mapped to the 'fname' property of a Payload object + + + Fifth - will be mapped to MessageHeaders + + + + + A Map-typed argument does not strictly require the use of the @Headers annotation. In other words + the following is also valid: public void bar(String payload, Map<String, Object> headerMap) + However this can lead to unresolvable ambiguities if the payload is itself a Map. For that reason, we + highly recommend using the annotation whenever expecting the headers. For a much more detailed + description, see the javadoc for MethodParameterMessageMapper. + + + + For several of these annotations, when a Message-handling method returns a non-null value, the endpoint will + attempt to send a reply. This is consistent across both configuration options (namespace and annotations) in + that such an endpoint's output channel will be used if available, and the REPLY_CHANNEL message header value + will be used as a fallback. + + + The combination of output channels on endpoints and the reply channel message header enables a pipeline approach + where multiple components have an output channel, and the final component simply allows the reply message to be + forwarded to the reply channel as specified in the original request message. In other words, the final component + depends on the information provided by the original sender and can dynamically support any number of clients as a + result. This is an example of Return Address. + + + In addition to the examples shown here, these annotations also support inputChannel and outputChannel properties. + public class FooService { + + @ServiceActivator(inputChannel="input", outputChannel="output") + public void bar(String payload, @Headers Map<String, Object> headerMap) { + ... + } + +} + That provides a pure annotation-driven alternative to the XML configuration. However, it is generally recommended + to use XML for the endpoints, since it is easier to keep track of the overall configuration in a single, external + location (and besides the namespace-based XML configuration is not very verbose). If you do prefer to provide + channels with the annotations however, you just need to enable a SI Annotations BeanPostProcessor. The following element should + be added: ]]> + + When configuring the "inputChannel" and "outputChannel" with annotations, the "inputChannel" + must be a reference to a SubscribableChannel instance. + Otherwise, it would be necessary to also provide the full poller configuration via annotations, and those + settings (e.g. the trigger for scheduling the poller) should be externalized rather than hard-coded within + an annotation. If the input channel that you want to receive Messages from is indeed a + PollableChannel instance, one option to consider is the Messaging Bridge. + Spring Integration's "bridge" element can be used to connect a PollableChannel directly to a + SubscribableChannel. Then, the polling metadata is externally configured, but the annotation option is + still available. For more detail see . + + +
+ +
+ Message Mapping rules and conventions + Spring Integration implements a flexible facility to map Messages to Methods and their arguments without + providing extra configuration by relying on some default rules as well as defining certain conventions. + +
+ Simple Scenarios + + + Single un-annotated parameter (object or primitive) which is not a Map/Properties with non-void return type; + + public String foo(Object o); + Details: + Input parameter is Message Payload. If parameter type is not compatible with Message Payload an + attempt will be made to convert it using Conversion Service provided by Spring 3.0. The return value + will be incorporated as a Payload of the returned Message + + + Single un-annotated parameter (object or primitive) which is not a Map/Properties with Message return type; + + public Message  foo(Object o); + Details: + Input parameter is Message Payload. If parameter type is not compatible with Message Payload an attempt + will be made to convert it using Conversion Service provided by Spring 3.0. The return value is a newly constructed + Message that will be sent to the next destination. + + + Single parameter which is a Message or its subclass with arbitrary object/primitive return type; + + public int foo(Message  msg); + Details: + Input parameter is Message itself. The return value will become a payload of the + Message that will be sent to the next destination. + + + Single parameter which is a Message or its subclass with Message or its subclass as a return type; + + public Message foo(Message msg); + Details: + Input parameter is Message itself. The return value is a newly constructed Message that will be sent to the next destination. + + + Single parameter which is of type Map or Properties with Message as a return type; + + public Message foo(Map m); + Details: + This one is a bit interesting. Although at first it might seem like an easy mapping straight to Message Headers, + the preference is always given to a Message Payload. This means that if Message Payload is of type Map, this input argument will + represent Message Payload. However if Message Payload is not of type Map, then no conversion via Conversion Service will be + attempted and the input argument will be mapped to Message Headers. + + + Two parameters where one of them is arbitrary non-Map/Properties type object/primitive and another is Map/Properties type object (regardless of the return) + + public Message foo(Map h, <T> t); + Details: + This combination contains two input parameters where one of them is of type Map. Naturally the non-Map parameters (regardless of the order) will + be mapped to a Message Payload and the Map/Properties (regardless of the order) will be mapped to  Message Headers giving you a nice POJO way + of interacting with Message structure. + + + No parameters (regardless of the return) + + public String foo(); + Details: + This Message Handler method will be invoked based on the Message sent to the input channel this handler is hooked up to, + however no Message data will be mapped, thus making Message act as event/trigger to invoke such handlerThe output will be + mapped according to the rules above + + + No parameters, void return + + public void foo(); + Details: + Same as above, but no output  + + + Annotation based mappings + + Annotation based mapping is the safest and least ambiguous approach to map Messages to Methods. There wil be many pointers to annotation + based mapping throughout this manual, however here are couple of examples: + + + public String foo(@Payload String s,  @Header("foo") String b)  + Very simple and explicite way of mapping Messages to method. As you'll see later on without annotation this signature + would result in the ambiguous condition, however by explicitly mapping first argument to a Message Payload and second argument to + a value of the 'foo' Message Header we have avoided ambiguity. + + public String foo(@Payload String s,  @RequestParam("foo") String b)  + Looks almost identical to the previous example, however @RequestMapping or any other non-SI mapping annotation + is irrelevant  and therefore will be ignored leaving the second parameter unmapped. And although the second parameters could + easily be mapped to a Payload, there can only be one Payload, therefore this method becomes ambiguous.  + + public String foo(String s,  @Header("foo") String b)  + The same as above. The only difference is that the first argument will be mapped to Message Payload implicitly. + + public String foo(@Headers Map m,  @Header("foo")Map f, @Header("bar") String bar) + Yet another signature that would definitely be treated as ambiguous because it has more then 2 arguments, + plus two of them are Maps, however with annotation-based mapping ambiguity is easily avoided. In this example + the first argument is mapped to all the Message Headers, while second and third argument map to the values of Message Headers 'foo' and 'bar'. +
+ +
+ Complex Scenarios + + Multiple parameters: + Multiple parameters could create a lot of ambiguity with regards to determining the appropriate mappings. The general advice is to annotate your method parameters with @Payload and/or @Header/@Headers +Below are some of the examples of ambiguous conditions which result in exception being raised. + + public String foo(String s, int i) + - the two parameters are equal in weight, therefore no way to determine which one is a payload and what to do with another. + + public String foo(String s, Map m, String b) + - almost the same as above. Although Map could be easily mapped to Message Headers, there is no way to determine what to do with two Strings. + + public String foo(Map m, Map f) + - although one might argue that one Map could be mapped to Message Payload and another one to Message Headers, it would be unreasonable to rely on the order (e.g., first is Payload, second Headers) + + + Basically any method signature with more then one method argument which is not (Map, <T>) and those parameters are not annotated will result in the ambiguous condition thus triggering an exception. + + + Multiple methods: + + Message Handlers with multiple methods are mapped based on the same rules that are described above, however some scenarios might still look confusing. + + Multiple methods (same or different name) with legal (mappable) signatures: + + public class Foo{ + public String foo(String str, Map m); + + public String foo(Map m) +} + As you can see, the Message could be mapped to either method. The first method would be invoked where Message Payload + could be mapped to 'str'  and Message Headers could be mapped to 'm'. The second method could easily also be a candidate where + only Message Headers are mapped to 'm'. To make meters worse both methods have the same name which at first might look very + ambiguous considering the following configuration: + + +]]> + At this point it would be important to understand Spring Integration mapping Conventions where at the very core, + mappings are based on Payload first and everything else next. In other words the method whose argument could be mapped + to a Payload will take precedence over all other methods. + + On the other hand let's look at slightly different example: + public class Foo{ + public String foo(String str, Map m); + + public String foo(String str) +} + + If you look at it you can probably see a truly an ambiguous condition. In this example since both methods have signatures that + could be mapped to a Message Payload. They also have the same name. Such handler will trigger an exception. +However if method names were different you could influence the mapping with 'method' attribute (see below): + public class Foo{ + public String foo(String str, Map m); + + public String bar(String str) +} + + +]]> + + Now there is no ambiguity since the configuration explicitly maps to 'bar' method which has no name conflicts. +
+
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/delayer.xml b/spring-integration-reference/src/delayer.xml new file mode 100644 index 0000000000..9942e1e249 --- /dev/null +++ b/spring-integration-reference/src/delayer.xml @@ -0,0 +1,62 @@ + + + + Delayer + +
+ Introduction + + A Delayer is a simple endpoint that allows a Message flow to be delayed by a certain interval. When + a Message is delayed, the original sender will not block. Instead, the delayed Messages will be + scheduled with an instance of java.util.concurrent.ScheduledExecutorService + to be sent to the output channel after the delay has passed. This approach is scalable even for + rather long delays, since it does not result in a large number of blocked sender Threads. On the + contrary, in the typical case a thread pool will be used for the actual execution of releasing the + Messages. Below you will find several examples of configuring a Delayer. + +
+ +
+ The <delayer> Element + + The <delayer> element is used to delay the Message flow between two Message Channels. + As with the other endpoints, you can provide the "input-channel" and "output-channel" attributes, + but the delayer also requires at least the 'default-delay' attribute with the number of milliseconds + that each Message should be delayed. + ]]> + If you need per-Message determination of the delay, then you can also provide the name of a header + within the 'delay-header-name' attribute: + ]]> + In the example above the 3 second delay would only apply in the case that the header value is + not present for a given inbound Message. If you only want to apply a delay to Messages that have + an explicit header value, then you can set the 'default-delay' to 0. For any Message that has a + delay of 0 (or less), the Message will be sent directly. In fact, if there is not a positive delay + value for a Message, it will be sent to the output channel on the calling Thread. + + The delay handler actually supports header values that represent an interval in milliseconds (any + Object whose toString() method produces a value that can be parsed into a + Long) as well as java.util.Date instances representing an absolute time. + In the former case, the milliseconds will be counted from the current time (e.g. a value of 5000 + would delay the Message for at least 5 seconds from the time it is received by the Delayer). In + the latter case, with an actual Date instance, the Message will not be released until that Date + occurs. In either case, a value that equates to a non-positive delay, or a Date in the past, will + not result in any delay. Instead, it will be sent directly to the output channel in the original + sender's Thread. + + + + The delayer delegates to an instance of Spring's TaskScheduler abstraction. + The default scheduler is a ThreadPoolTaskScheduler instance with a pool size of 1. + If you want to delegate to a different scheduler, you can provide a reference through the delayer element's + 'scheduler' attribute: + + + ]]> + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/endpoint.xml b/spring-integration-reference/src/endpoint.xml new file mode 100644 index 0000000000..c819804662 --- /dev/null +++ b/spring-integration-reference/src/endpoint.xml @@ -0,0 +1,272 @@ + + + + Message Endpoints + + The first part of this chapter covers some background theory and reveals quite a bit about the underlying API + that drives Spring Integration's various messaging components. This information can be helpful if you want to + really understand what's going on behind the scenes. However, if you want to get up and running with the + simplified namespace-based configuration of the various elements, feel free to skip ahead to + for now. + + + As mentioned in the overview, Message Endpoints are responsible for connecting the various messaging components to + channels. Over the next several chapters, you will see a number of different components that consume Messages. Some + of these are also capable of sending reply Messages. Sending Messages is quite straightforward. As shown above in + , it's easy to send a Message to a Message Channel. However, + receiving is a bit more complicated. The main reason is that there are two types of consumers: + Polling Consumers and + Event Driven Consumers. + + + Of the two, Event Driven Consumers are much simpler. Without any need to manage and schedule a separate poller + thread, they are essentially just listeners with a callback method. When connecting to one of Spring Integration's + subscribable Message Channels, this simple option works great. However, when connecting to a buffering, pollable + Message Channel, some component has to schedule and manage the polling thread(s). Spring Integration provides + two different endpoint implementations to accommodate these two types of consumers. Therefore, the consumers + themselves can simply implement the callback interface. When polling is required, the endpoint acts as a + "container" for the consumer instance. The benefit is similar to that of using a container for hosting + Message Driven Beans, but since these consumers are simply Spring-managed Objects running within an + ApplicationContext, it more closely resembles Spring's own MessageListener containers. + + +
+ Message Handler + + Spring Integration's MessageHandler interface is implemented by many of the + components within the framework. In other words, this is not part of the public API, and a developer would not + typically implement MessageHandler directly. Nevertheless, it is used by a Message + Consumer for actually handling the consumed Messages, and so being aware of this strategy interface does help in + terms of understanding the overall role of a consumer. The interface is defined as follows: + public interface MessageHandler { + + void handleMessage(Message<?> message); + +} + Despite its simplicity, this provides the foundation for most of the components that will be covered in the + following chapters (Routers, Transformers, Splitters, Aggregators, Service Activators, etc). Those components + each perform very different functionality with the Messages they handle, but the requirements for actually + receiving a Message are the same, and the choice between polling and event-driven behavior is also the same. + Spring Integration provides two endpoint implementations that "host" these callback-based handlers and allow + them to be connected to Message Channels. + +
+ +
+ Event Driven Consumer + + Because it is the simpler of the two, we will cover the Event Driven Consumer endpoint first. You may recall that + the SubscribableChannel interface provides a subscribe() + method and that the method accepts a MessageHandler parameter (as shown in + ): + +subscribableChannel.subscribe(messageHandler); + + Since a handler that is subscribed to a channel does not have to actively poll that channel, this is an + Event Driven Consumer, and the implementation provided by Spring Integration accepts a + a SubscribableChannel and a MessageHandler: + SubscribableChannel channel = (SubscribableChannel) context.getBean("subscribableChannel"); + +EventDrivenConsumer consumer = new EventDrivenConsumer(channel, exampleHandler); + +
+ +
+ Polling Consumer + + Spring Integration also provides a PollingConsumer, and it can be instantiated in + the same way except that the channel must implement PollableChannel: + PollableChannel channel = (PollableChannel) context.getBean("pollableChannel"); + +PollingConsumer consumer = new PollingConsumer(channel, exampleHandler); + + + There are many other configuration options for the Polling Consumer. For example, the trigger is a required property: + +PollingConsumer consumer = new PollingConsumer(channel, handler); + +consumer.setTrigger(new IntervalTrigger(30, TimeUnit.SECONDS)); + Spring Integration currently provides two implementations of the Trigger + interface: IntervalTrigger and CronTrigger. The + IntervalTrigger is typically defined with a simple interval (in milliseconds), but + also supports an 'initialDelay' property and a boolean 'fixedRate' property (the default is false, i.e. + fixed delay): + IntervalTrigger trigger = new IntervalTrigger(1000); +trigger.setInitialDelay(5000); +trigger.setFixedRate(true); + The CronTrigger simply requires a valid cron expression (see the Javadoc for details): + CronTrigger trigger = new CronTrigger("*/10 * * * * MON-FRI"); + + + In addition to the trigger, several other polling-related configuration properties may be specified: + +PollingConsumer consumer = new PollingConsumer(channel, handler); + +consumer.setMaxMessagesPerPoll(10); + +consumer.setReceiveTimeout(5000); + + + The 'maxMessagesPerPoll' property specifies the maximum number of messages to receive within a given poll + operation. This means that the poller will continue calling receive() without waiting + until either null is returned or that max is reached. For example, if a poller has a 10 second + interval trigger and a 'maxMessagesPerPoll' setting of 25, and it is polling a channel that has 100 messages + in its queue, all 100 messages can be retrieved within 40 seconds. It grabs 25, waits 10 seconds, grabs the + next 25, and so on. + + + The 'receiveTimeout' property specifies the amount of time the poller should wait if no messages are + available when it invokes the receive operation. For example, consider two options that seem similar on + the surface but are actually quite different: the first has an interval trigger of 5 seconds and a receive + timeout of 50 milliseconds while the second has an interval trigger of 50 milliseconds and a receive timeout + of 5 seconds. The first one may receive a message up to 4950 milliseconds later than it arrived on the channel + (if that message arrived immediately after one of its poll calls returned). On the other hand, the second + configuration will never miss a message by more than 50 milliseconds. The difference is that the second + option requires a thread to wait, but as a result it is able to respond much more quickly to arriving messages. + This technique, known as "long polling", can be used to emulate event-driven behavior on a polled source. + + + A Polling Consumer may also delegate to a Spring TaskExecutor, and it can + be configured to participate in Spring-managed transactions. The following example shows the configuration of both: + +PollingConsumer consumer = new PollingConsumer(channel, handler); + +TaskExecutor taskExecutor = (TaskExecutor) context.getBean("exampleExecutor"); +consumer.setTaskExecutor(taskExecutor); + +PlatformTransactionManager txManager = (PlatformTransationManager) context.getBean("exampleTxManager"); +consumer.setTransactionManager(txManager); + The examples above show dependency lookups, but keep in mind that these consumers will most often be configured + as Spring bean definitions. In fact, Spring Integration also provides a + FactoryBean that creates the appropriate consumer type based on the type of + channel, and there is full XML namespace support to even further hide those details. The namespace-based + configuration will be featured as each component type is introduced. + + Many of the MessageHandler implementations are also capable of generating reply + Messages. As mentioned above, sending Messages is trivial when compared to the Message reception. Nevertheless, + when and how many reply Messages are sent depends on the handler + type. For example, an Aggregator waits for a number of Messages to arrive and is often + configured as a downstream consumer for a Splitter which may generate multiple + replies for each Message it handles. When using the namespace configuration, you do not strictly need to know + all of the details, but it still might be worth knowing that several of these components share a common base + class, the AbstractReplyProducingMessageHandler, and it provides a + setOutputChannel(..) method. + + +
+ +
+ Namespace Support + + Throughout the reference manual, you will see specific configuration examples for endpoint elements, such as + router, transformer, service-activator, and so on. Most of these will support an "input-channel" attribute and + many will support an "output-channel" attribute. After being parsed, these endpoint elements produce an instance + of either the PollingConsumer or the + EventDrivenConsumer depending on the type of the "input-channel" that is + referenced: PollableChannel or SubscribableChannel + respectively. When the channel is pollable, then the polling behavior is determined based on the endpoint + element's "poller" sub-element. For example, a simple interval-based poller with a 1-second interval would be + configured like this: + + + +]]> + For a poller based on a Cron expression, use the "cron-trigger" child element instead: + + + + + ]]> + + + If the input channel is a PollableChannel, then the poller configuration is + required. Specifically, as mentioned above, the 'trigger' is a required property of the PollingConsumer class. + Therefore, if you omit the "poller" sub-element for a Polling Consumer endpoint's configuration, an Exception + may be thrown. However, it is also possible to create top-level pollers in which case only a "ref" is required: + + + + + + + ]]> + In fact, to simplify the configuration, you can define a global default poller. A single top-level poller within + an ApplicationContext may have the default attribute with a value of "true". In that case, any + endpoint with a PollableChannel for its input-channel that is defined within the same ApplicationContext and has + no explicitly configured 'poller' sub-element will use that default. + + + + + + ]]> + + + Spring Integration also provides transaction support for the pollers so that each receive-and-forward + operation can be performed as an atomic unit-of-work. To configure transactions for a poller, simply add the + <transactional/> sub-element. The attributes for this element should be familiar to anyone who has + experience with Spring's Transaction management: + + + +]]> + + + The polling threads may be executed by any instance of Spring's TaskExecutor + abstraction. This enables concurrency for an endpoint or group of endpoints. As of Spring 3.0, there is a "task" + namespace in the core Spring Framework, and its <executor/> element supports the creation of a simple thread + pool executor. That element accepts attributes for common concurrency settings such as pool-size and queue-capacity. + Configuring a thread-pooling executor can make a substantial difference in how the endpoint performs under load. These + settings are available per-endpoint since the performance of an endpoint is one of the major factors to consider + (the other major factor being the expected volume on the channel to which the endpoint subscribes). To enable + concurrency for a polling endpoint that is configured with the XML namespace support, provide the 'task-executor' + reference on its <poller/> element and then provide one or more of the properties shown below: + + + + + ]]> + If no 'task-executor' is provided, the consumer's handler will be invoked in the caller's thread. Note that the + "caller" is usually the default TaskScheduler + (see ). Also, keep in mind that the 'task-executor' attribute can + provide a reference to any implementation of Spring's TaskExecutor interface by + specifying the bean name. The "executor" element above is simply provided for convenience. + + + As mentioned in the background section for Polling Consumers above, you can also configure a Polling Consumer + in such a way as to emulate event-driven behavior. With a long receive-timeout and a short interval-trigger, + you can ensure a very timely reaction to arriving messages even on a polled message source. Note that this + will only apply to sources that have a blocking wait call with a timeout. For example, the File poller does + not block, each receive() call returns immediately and either contains new files or not. Therefore, even if + a poller contains a long receive-timeout, that value would never be usable in such a scenario. On the other + hand when using Spring Integration's own queue-based channels, the timeout value does have a chance to + participate. The following example demonstrates how a Polling Consumer will receive Messages nearly + instantaneously. + + + + + ]]> + Using this approach does not carry much overhead since internally it is nothing more then a timed-wait thread + which does not require nearly as much CPU resource usage as a thrashing, infinite while loop for example. + + +
+ \ No newline at end of file diff --git a/spring-integration-reference/src/event.xml b/spring-integration-reference/src/event.xml new file mode 100644 index 0000000000..c6048ba2e7 --- /dev/null +++ b/spring-integration-reference/src/event.xml @@ -0,0 +1,35 @@ + + + + + Spring ApplicationEvent Support + + + Spring Integration provides support for inbound and outbound ApplicationEvents + as defined by the underlying Spring Framework. For more information about the events and listeners, + refer to the Spring Reference Manual. + + +
+ Receiving Spring ApplicationEvents + + To receive events and send them to a channel, simply define an instance of Spring Integration's + ApplicationEventListeningChannelAdapter. This class is an implementation of + Spring's ApplicationListener interface. By default it will pass all + received events as Spring Integration Messages. To limit based on the type of event, configure the + list of event types that you want to receive with the 'eventTypes' property. + +
+ +
+ Sending Spring ApplicationEvents + + To send Spring ApplicationEvents, create an instance of the + ApplicationEventPublishingMessageHandler and register it within an endpoint. + This implementation of the MessageHandler interface also implements + Spring's ApplicationEventPublisherAware interface and thus acts as a + bridge between Spring Integration Messages and ApplicationEvents. + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/file.xml b/spring-integration-reference/src/file.xml new file mode 100644 index 0000000000..bc714f8f0f --- /dev/null +++ b/spring-integration-reference/src/file.xml @@ -0,0 +1,199 @@ + + + + File Support + +
+ Introduction + + Spring Integration's File support extends the Spring Integration Core with + a dedicated vocabulary to deal with reading, writing, and transforming files. + It provides a namespace that enables elements defining Channel Adapters dedicated + to files and support for Transformers that can read file contents into strings or + byte arrays. + + + This section will explain the workings of FileReadingMessageSource + and FileWritingMessageHandler and how to configure them as + beans. Also the support for dealing with files through file specific + implementations of Transformer will be discussed. Finally the + file specific namespace will be explained. + +
+ +
+ Reading Files + + A FileReadingMessageSource can be used to consume files from the filesystem. + This is an implementation of MessageSource that creates messages from + a file system directory. ]]> + + + To prevent creating messages for certain files, you may supply a + FileListFilter. By default, an + AcceptOnceFileListFilter is used. This filter + ensures files are picked up only once from the directory. + ]]> + + + A common problem with reading files is that a file may be detected before + it is ready. The default AcceptOnceFileListFilter + does not prevent this. In most cases, this can be prevented if the + file-writing process renames each file as soon as it is ready for + reading. A pattern-matching filter that accepts only files that are + ready (e.g. based on a known suffix), composed with the default + AcceptOnceFileListFilter allows for this. + The CompositeFileListFilter enables the + composition. + + + + + + + + + + +]]> + + + The configuration can be simplified using the file specific namespace. To do + this use the following template. + + +]]> + Within this namespace you can reduce the FileReadingMessageSource and wrap + it in an inbound Channel Adapter like this: + + + + + ]]> + The first channel adapter is relying on the default filter that just prevents + duplication, the second is using a custom filter, and the third is using the + filename-pattern attribute to add a Pattern + based filter to the FileReadingMessageSource. + The file-name-pattern and filter attributes are mutually exclusive, but + you can use a CompositeFileListFilter to use any combination of filters, including a + pattern based filter to fit your particular needs. + +
+ +
+ Writing files + + To write messages to the file system you can use a + FileWritingMessageHandler. This class can deal with + File, String, or byte array payloads. In its simplest form the + FileWritingMessageHandler only requires a + destination directory for writing the files. The name of the file to be + written is determined by the handler's FileNameGenerator. + The default implementation looks for a Message header whose key matches + the constant defined as FileHeaders.FILENAME. + + + Additionally, you can configure the encoding and the charset that + will be used in case of a String payload. + + + To make things easier you can configure the FileWritingMessageHandler as + part of an outbound channel adapter using the namespace. + ]]> + + + The namespace based configuration also supports a delete-source-files attribute. + If set to true, it will trigger deletion of the original source files after writing + to a destination. The default value for that flag is false. + ]]> + + + The delete-source-files attribute will only have an effect if the inbound + Message has a File payload or if the FileHeaders.ORIGINAL_FILE header + value contains either the source File instance or a String representing the original file path. + + + + + In cases where you want to continue processing messages based on the written File you can use + the outbound-gateway instead. It plays a very similar role as the + outbound-channel-adapter. However after writing the File, it will also send it + to the reply channel as the payload of a Message. + ]]> + + + The 'outbound-gateway' works well in cases where you want to first move a File and then send it + through a processing pipeline. In such cases, you may connect the file namespace's + 'inbound-channel-adapter' element to the 'outbound-gateway' and then connect that gateway's + reply-channel to the beginning of the pipeline. + + + If you have more elaborate requirements or need to support additional payload types as input + to be converted to file content you could extend the FileWritingMessageHandler, but a much + better option is to rely on a Transformer. + +
+ +
+ File Transformers + + To transform data read from the file system to objects and the other way around you need + to do some work. Contrary to FileReadingMessageSource and to a + lesser extent FileWritingMessageHandler, it is very likely that you + will need your own mechanism to get the job done. For this you can implement the + Transformer interface. Or extend the + AbstractFilePayloadTransformer for inbound messages. Some obvious + implementations have been provided. + + + FileToByteArrayTransformer transforms Files into byte[]s using + Spring's FileCopyUtils. It is often better to use a sequence of + transformers than to put all transformations in a single class. In that case the File to + byte[] conversion might be a logical first step. + + + FileToStringTransformer will convert Files to Strings as the name + suggests. If nothing else, this can be useful for debugging (consider using with a Wire Tap). + + + To configure File specific transformers you can use the appropriate elements from the file namespace. + + + ]]> + The delete-files option signals to the transformer that it should delete + the inbound File after the transformation is complete. This is in no way a replacement for using the + AcceptOnceFileListFilter when the FileReadingMessageSource is being used in a + multi-threaded environment (e.g. Spring Integration in general). + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/filter.xml b/spring-integration-reference/src/filter.xml new file mode 100644 index 0000000000..8b7c340845 --- /dev/null +++ b/spring-integration-reference/src/filter.xml @@ -0,0 +1,86 @@ + + + + Filter + +
+ Introduction + + Message Filters are used to decide whether a Message should be passed along or dropped based on some criteria + such as a Message Header value or even content within the Message itself. Therefore, a Message Filter is similar + to a router, except that for each Message received from the filter's input channel, that same Message may or may + not be sent to the filter's output channel. Unlike the router, it makes no decision regarding + which Message Channel to send to but only decides whether to send. + + As you will see momentarily, the Filter does also support a discard channel, so in certain cases it + can play the role of a very simple router (or "switch") based on a boolean condition. + + + + In Spring Integration, a Message Filter may be configured as a Message Endpoint that delegates to some + implementation of the MessageSelector interface. That interface is itself quite + simple: message); + + }]]> + The MessageFilter constructor accepts a selector instance: + + +
+ +
+ The <filter> Element + + The <filter> element is used to create a Message-selecting endpoint. In addition to "input-channel" + and "output-channel" attributes, it requires a "ref". The "ref" may point to a MessageSelector implementation: + + + ]]> + + + Alternatively, the "method" attribute can be added at which point the "ref" may refer to any object. + The referenced method may expect either the Message type or the payload type of + inbound Messages. The return value of the method must be a boolean value. Any time the method returns 'true', + the Message will be passed along to the output-channel. + + + ]]> + + + If the selector or adapted POJO method returns false, there are a few settings that control the + fate of the rejected Message. By default (if configured like the example above), the rejected Messages will + be silently dropped. If rejection should instead indicate an error condition, then set the + 'throw-exception-on-rejection' flag to true: + ]]> + If you want the rejected messages to go to a specific channel, provide that reference as the 'discard-channel': + ]]> + + + A common usage for Message Filters is in conjunction with a Publish Subscribe Channel. Many filter endpoints may + be subscribed to the same channel, and they decide whether or not to pass the Message for the next endpoint which + could be any of the supported types (e.g. Service Activator). This provides a reactive + alternative to the more proactive approach of using a Message Router with a single + Point-to-Point input channel and multiple output channels. + + + Using a "ref" attribute is generally recommended if the custom filter implementation can be reused in other + <filter> definitions. However if the custom filter implementation should be scoped to a + single <filter> element, provide an inner bean definition: + + +]]> + + + + Using both the "ref" attribute and an inner handler definition in the same <filter> configuration + is not allowed, as it creates an ambiguous condition, and it will therefore result in an Exception being thrown. + + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/gateway.xml b/spring-integration-reference/src/gateway.xml new file mode 100644 index 0000000000..54e0df16b0 --- /dev/null +++ b/spring-integration-reference/src/gateway.xml @@ -0,0 +1,103 @@ + + + + Inbound Messaging Gateways + +
+ SimpleMessagingGateway + + Even though the MessageChannelTemplate is fairly straightforward, it does not hide the + details of messaging from your application code. To support working with plain Objects instead of messages, + Spring Integration provides SimpleMessagingGateway with the following methods: + sendAndReceiveMessage(Object object);]]> + It enables configuration of a request and/or reply channel and delegates to instances of the + InboundMessageMapper and OutboundMessageMapper + strategy interfaces. + SimpleMessagingGateway gateway = new SimpleMessagingGateway(inboundMapper, outboundMapper); + gateway.setRequestChannel(requestChannel); + gateway.setReplyChannel(replyChannel); + Object result = gateway.sendAndReceive("test"); + +
+ +
+ GatewayProxyFactoryBean + + Working with Objects instead of Messages is an improvement. However, it would be even better to have no + dependency on the Spring Integration API at all - including the gateway class. For that reason, Spring + Integration also provides a GatewayProxyFactoryBean that generates a proxy for + any interface and internally invokes the gateway methods shown above. Namespace support is also + provided as demonstrated by the following example. + ]]> + Then, the "fooService" can be injected into other beans, and the code that invokes the methods on that + proxied instance of the FooService interface has no awareness of the Spring Integration API. The general + approach is similar to that of Spring Remoting (RMI, HttpInvoker, etc.). See the "Samples" Appendix for + an example that uses this "gateway" element (in the Cafe demo). + + + The reason that the attributes on the 'gateway' element are named 'default-request-channel' and + 'default-reply-channel' is that you may also provide per-method channel references by using the + @Gateway annotation. + + + + It is also possible to pass values to be interpreted as Message headers on the Message + that is created and sent to the request channel by using the @Header annotation: + + + + + If you prefer XML way of configuring Gateway methods, you can provide method sub-elements + to the gateway configuration (see below) + + + + +]]> + + + You can also provide individual headers per method invocation via XML. + This could be very useful if headers you want to set are static in nature and you don't want + to embed them in the gateway's method signature via @Header annotation. + For example; in the Loan Broker example we want to influence how aggregation of the Loan quotes + will be done based on what type of request was initiated (single quote or all quotes). Determining the + type of the request by evaluating what gateway's method was invoked, although possible would + violate the separation of concerns paradigm (method is a java artifact),  but expressing your + intention (meta information) via Message headers is natural to Messaging architecture. + + + + + + + + +]]> + In the above case you can clearly see how a different header value will be set for the 'RESPONSE_TYPE' + header based on the gateway's method. + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/http.xml b/spring-integration-reference/src/http.xml new file mode 100644 index 0000000000..55a8f56c60 --- /dev/null +++ b/spring-integration-reference/src/http.xml @@ -0,0 +1,128 @@ + + + + HTTP Support + +
+ Introduction + + The HTTP support allows for the making of HTTP requests and the processing of inbound Http requests. Because interaction over HTTP is always synchronous, even if all that is returned is a 200 status code the Http support consists of two gateway implementations + HttpInboundEndpoint and HttpOutboundEndpoint. + +
+ +
+ Http Inbound Gateway + + To receive messages over http you need to use an HttpInboundEndpoint. In common with the HttpInvoker + support the Http Inbound Gateway needs to be deployed within a servlet container. The easiest way to do this is to provide a servlet + definition in web.xml, see + for further details. Below is an example bean definition for a simple HttpInboundEndpoint + + + +]]> + The HttpInboundEndpoint accepts an instance of InboundRequestMapper which allows + customisation of the mapping from HttpServletRequest to Message. If none is + provided an instance of DefaultInboundRequestMapper will be used. This encapsulates a simple strategy, which for + example will create a String message for a POST request where the content type starts with "text", see the Javadoc for + full details. + + Starting with this release MultiPart File support was implemented. If the request has been wrapped as a + MultipartHttpServletRequest, then the 'content type' can be checked. If it is known, and + begins with "text", then the MultipartFile will be copied to a String in the parameter + map. If the content type does not begin with "text", then the MultipartFile will be copied + to a byte array within the parameter map instead. + + The HttpInboundEndpoint will locate a MultipartResolver in the context if one exists with the bean name + "multipartResolver" (the same name expected by Spring's DispatcherServlet). If it does in fact locate that + bean, then the support for MultipartFiles will be enabled on the inbound request mapper. Otherwise, it will + fail when trying to map a multipart-file request to a Spring Integration Message. For more on Spring's + support for MultipartResolvers, refer to the Spring Reference Manual. + + + + In sending a response to the client there are a number of ways to customise the behaviour of the gateway. By default the gateway will + simply acknowledge that the request was received by sending a 200 status code back. It is possible to customise this response by providing an + implementation of the Spring MVC View which will be invoked with the created Message. + In the case that the gateway should expect a reply to the Message then setting the expectReply flag will cause + the gateway to wait for a response Message before creating an Http response. Below is an example of a gateway + configured to use a custom view and to wait for a response. It also shows how to customise the Http methods accepted by the gateway, which + are POST and GET by default. + + + + + + + GET + DELETE + + + + +]]> + The message created from the request will be available in the Model map. The key that is used + for that map entry by default is 'requestMessage', but this can be overridden by setting the + 'requestKey' property on the endpoint's configuration. + +
+ +
+ Http Outbound Gateway + + + To configure the HttpOutboundEndpoint write a bean definition like this: + + +]]> + This bean definition will execute Http requests by first converting the message to the Http request using an instance of + DefaultOutboundRequestMapper. This will expect to find the request URL in the message header under + the key HttpHeaders.REQUEST_URL. It is also possible to set a default target URL as a constructor argument + along with other options as shown below. + + + + + +]]> +By default the Http request will be made using an instance of SimpleHttpRequestExecutor which uses the JDK + HttpURLConnection. Use of the Apache Commons Http Client is also supported through the provided + CommonsHttpRequestExecutor which can be injected into the outbound gateway. + +
+ +
+ Http Namespace Support + + Spring Integration provides an "http" namespace and schema definition. To include it in your + configuration, simply provide the following URI within a namespace declaration: + 'http://www.springframework.org/schema/integration/http'. The schema location should then map to + 'http://www.springframework.org/schema/integration/http/spring-integration-http-1.0.xsd'. + + + To configure an inbound http channel adapter which is an instance of HttpInboundEndpoint configured + not to expect a response. + ]]> + + + To configure an inbound http gateway which expects a response. + ]]> + + + To configure the outbound gateway you can use the namespace support as well. The following code snippet shows the different configuration options for an outbound Http gateway. + ]]> + If you want to provide a custom OutboundRequestMapper, then a reference may be supplied to the + 'request-mapper' attribute. In that case however you will not be allowed to set the default URL, + charset, and 'extract-request-payload' properties since those are all properties of the default + mapper (see the JavaDoc for DefaultOutboundRequestMapper for more information). + +
+ diff --git a/spring-integration-reference/src/httpinvoker.xml b/spring-integration-reference/src/httpinvoker.xml new file mode 100644 index 0000000000..da2492571e --- /dev/null +++ b/spring-integration-reference/src/httpinvoker.xml @@ -0,0 +1,101 @@ + + + + HttpInvoker Support + +
+ Introduction + + HttpInvoker is a Spring-specific remoting option that essentially enables Remote Procedure Calls (RPC) over HTTP. + In order to accomplish this, an outbound representation of a method invocation is serialized using standard Java + serialization and then passed within an HTTP POST request. After being invoked on the target system, the method's + return value is then serialized and written to the HTTP response. There are two main requirements. First, you + must be using Spring on both sides since the marshalling to and from HTTP requests and responses is handled by + the client-side invoker and server-side exporter. Second, the Objects that you are passing must implement + Serializable and be available on both the client and server. + + + While traditional RPC provides physical decoupling, it does not offer nearly the same degree + of logical decoupling as a messaging-based system. In other words, both participants in an + RPC-based invocation must be aware of a specific interface and specific argument types. Interestingly, in Spring + Integration, the "parameter" being sent is a Spring Integration Message, and the interface is an internal detail + of Spring Integration's implementation. Therefore, the RPC mechanism is being used as a + transport so that from the end user's perspective, it is not necessary to consider the + interface and argument types. It's just another adapter to enable messaging between two systems. + +
+ +
+ HttpInvoker Inbound Gateway + + To receive messages over http you can use an HttpInvokerInboundGateway. Here is an + example bean definition: + + + + + +]]> + Because the inbound gateway must be able to receive HTTP requests, it must be configured within a Servlet + container. The easiest way to do this is to provide a servlet definition in web.xml: + + inboundGateway + org.springframework.web.context.support.HttpRequestHandlerServlet +]]> + Notice that the servlet name matches the bean name. + + If you are running within a Spring MVC application and using the BeanNameHandlerMapping, then the servlet + definition is not necessary. In that case, the bean name for your gateway can be matched against the URL + path just like a Spring MVC Controller bean. + + +
+ +
+ HttpInvoker Outbound Gateway + + + + To configure the HttpInvokerOutboundGateway write a bean definition like this: + + +]]> + The outbound gateway is a MessageHandler and can therefore be registered with + either a PollingConsumer or EventDrivenConsumer. + The URL must match that defined by an inbound HttpInvoker Gateway as described in the previous section. + +
+ +
+ HttpInvoker Namespace Support + + Spring Integration provides an "httpinvoker" namespace and schema definition. To include it in your + configuration, simply provide the following URI within a namespace declaration: + 'http://www.springframework.org/schema/integration/httpinvoker'. The schema location should then map to + 'http://www.springframework.org/schema/integration/httpinvoker/spring-integration-httpinvoker-1.0.xsd'. + + + To configure the inbound gateway you can choose to use the namespace support for it. The following code snippet shows the different configuration options that are supported. + ]]> + + A 'reply-channel' may also be provided, but it is recommended to rely on the temporary anonymous channel + that will be created automatically for handling replies. + + + + To configure the outbound gateway you can use the namespace support as well. The following code snippet shows the different configuration for an outbound HttpInvoker gateway. Only the 'url' and 'request-channel' are required. + ]]> + +
+ \ No newline at end of file diff --git a/spring-integration-reference/src/ip.xml b/spring-integration-reference/src/ip.xml new file mode 100644 index 0000000000..32dd80ea19 --- /dev/null +++ b/spring-integration-reference/src/ip.xml @@ -0,0 +1,758 @@ + + + + TCP and UDP Support + + Spring Integration provides Channel Adapters for receiving and sending messages over internet protocols. Both UDP + (User Datagram Protocol) + and TCP (Transmission Control Protocol) adapters are provided. Each adapter provides for one-way communication + over the underlying protocol. + In addition, a simple inbound tcp gateway is provided. + +
+ Introduction + + Two flavors each of UDP inbound and outbound adapters are provided UnicastSendingMessageHandler + sends a datagram packet to a single destination. UnicastReceivingChannelAdapter receives + incoming datagram packets. MulticastSendingMessageHandler sends (broadcasts) datagram packets to + a multicast address. MulticastReceivingChannelAdapter receives incoming datagram packets + by joining to a multicast address. + + + Two flavors each of TCP inbound and outbound adapters are provided TcpNetSendingMessageHandler + and TcpNioSendingMessageHandler send messages over TCP. They are functionally equivalent, + but use different underlying technology for socket communication. Similarly, TcpNetReceivingChannelAdapter + and TcpNioReceivingChannelAdapter are the equivalent inbound channel adapters. + The choice of which to use in what circumstances is described below. + + + A simple inbound TCP gateway is provided; this allows for simple request/response processing. While + the gateway can support any number of connections, each connection can only process serially. The thread + that reads from the socket waits for, and sends, the response before reading again. + +
+
+ UDP Adapters + + ]]> + A simple UDP outbound channel adapter. + + When setting multicast to true, provide the multicast address in the host + attribute. + + + + UDP is an efficient, but unreliable protocol. Two attributes are added to improve reliability. When check-length is + set to true, the adapter precedes the message data with a length field (4 bytes in network byte order). This enables + the receiving side to verify the length of the packet received. If a receiving system uses a buffer that is too + short the contain the packet, the packet can be truncated. The length header provides a mechanism to detect this. + + + ]]> + An outbound channel adapter that adds length checking to the datagram packets. + + The recipient of the packet must also be configured to expect a length to precede the + actual data. For a Spring Integration UDP inbound channel adapter, set its + check-length attribute. + + + + The second reliability improvement allows an application-level acknowledgment protocol to be used. The receiver + must send an acknowledgment to the sender within a specified time. + + + ]]> + An outbound channel adapter that adds length checking to the datagram packets and waits for an acknowledgment. + + Setting acknowledge to true implies the recipient of the packet can interpret the header added to the packet + containing acknowledgment data (host and port). Most likely, the recipient will be a Spring Integration inbound + channel adapter. + + + When multicast is true, an additional attribute min-acks-for-success specifies + how many acknowledgments must be received within the ack-timeout. + + + + For even more reliable networking, TCP can be used. + + + ]]> + A basic unicast inbound udp channel adapter. + + + ]]> + A basic multicast inbound udp channel adapter. + +
+
+ TCP Adapters + + Two versions of TCP inbound and outbound channel adapters are provided; these adapters + use either java.net.Socket IO, or java.nio.channels.SocketChannel IO. The choice of which + to use depends on the application. The TcpNet* adapters use java.net.Socket and the TcpNio* + adapters use java.nio.channels.ChannelSocket. It is not anticipated that much difference in + performance, if any, would exist between these technologies on the outbound side. This is + because each outbound adapter sends data over only one socket. On the receiving side + however, consideration should be given to the number of connections. For the + TcpNetReceivingChannelAdapter a thread is dedicated to receiving + data on each connected socket; the pool size must therefore be set large enough to handle + the expected number of connections. For the TcpNioReceivingChannelAdapter + threads are used on an as-needed basis and it is likely that many fewer threads would be + needed. If a small number of connections is expected, we expect that the the TcpNetReceivingChannelAdapter + will give the best performance. For large number of connections, the TcpNioReceivingChannelAdapter will + likely give the best performance. In addition, the TcpNioReceivingChannelAdapter provides an + attribute using-direct-buffers which attempts to use direct buffers. See + java.nio.ByteBuffer for more information about direct buffers. + + It is not expected that direct buffers will offer much, if any, performance difference. You + should experiment with the use of TcpNxx* adapters, and direct buffers when using TcpNio* + adapters to determine the best performance in your environment. + + + + TCP is a streaming protocol; this means that some structure has to be provided to data + transported over TCP, so the receiver can demarcate the data into discrete messages. + Three standard message formats are provided for this purpose; you can also provide code + for your own custom format. The first of the three standard formats is length-header, in which case a 4 byte + length header precedes the data; this is the default. The second is stx-etx in which the message + data is preceded by an STX (0x02) character and terminated with an ETX (0x03) character. + The third is crlf in which the message is terminated with a carriage return and line feed + (\r\n). The first format (the default) is likely to be the most performant. This is because + we can determine exactly how many bytes to read to obtain the complete message. The other + two formats require examining each byte to determine if the end of the message has been + received. The length-header format can also handle binary data. The other two formats can only handle + text data (specifcally, data that does not contain characters 0x02 and 0x03 for stx-etx and + 0x0d and 0x0a for crlf). This limitation can be avoided by appropriate character escaping techniques + in the application layer. No such escaping is provided by the adapters; therefore it is not recommened + that these formats be used without some transformation if the data may contain these characters. + + + ]]> + A basic outbound tcp channel adapter. This adapter uses java.nio.channels.SocketChannel. + To use a java.net.Socket, set using-nio to false and + using-direct-buffers is not relevant. + + + ]]> + A basic inbound tcp channel adapter. This adapter uses java.nio.channels.SocketChannel. + To use a java.net.Socket, set using-nio to false and + using-direct-buffers is not relevant. + +
+
+ TCP Gateways + + The simple inbound TCP gateway SimpleTcpNetInboundGateway + and simple oubound TCP gateway SimpleTcpNetOutboundGateway + use java.net.Socket for communications. Each connection + can process a single request/response at a time. + + + The inbound gateway delegates to a subclass of the TcpNetReceivingChannelAdapter + described above, so please read that section for more information. After + constructing a message with the incoming payload and sending + it to the requestChannel, it waits for a response and sends the payload + from the response message by writing it to the socket, using the same + message format configured for the incoming message. + + + The outbound gateway delegates to a TcpNetSendingMessageHandler + described above, so please read that section for more information. After + sending a message over the socket, the thread waits for a response and + constructs a response message with a byte[] payload The incoming + response is decoded using the same + message format configured for the outgoing message. Communications over + the socket are single-threaded. Users should be aware that only one + message can be handled at a time and if another thread attempts to send + a message before the current response has been received, it will block. Only + when the inprocess message receives a response (or times out based on the + socket timeout option) will it proceed. + + + ]]> + A simple inbound TCP gateway; it uses '/r/n' delimited data and can be + used by a simple client such as telnet. + + + ]]> + A simple oubound TCP gateway; it uses '/r/n' delimited data. + +
+
+ IP Endpoint Attributes + + + IP Outbound Channel Adapter Attributes + + + + + + + + + + Attribute Name + TCP? + UDP? + Allowed Values + Attribute Description + + + + + protocol + Y + Y + tcp, udp + Determines whether the adapter uses TCP or UDP, over IP. + + + host + Y + Y + + The host name or ip address of the destination. For multicast udp + adapters, the multicast address. + + + port + Y + Y + + The port on the destination. + + + multicast + N + Y + true, false + Whether or not the udp adapter uses multicast. + + + acknowledge + N + Y + true, false + Whether or not a udp adapter requires an acknowledgment from the destination. + when enabled, requires setting the following 4 attributes. + + + ack-host + N + Y + + When acknowledge is true, indicates the host or ip address to which the + acknowledgment should be sent. Usually the current host, but may be + different, for example when Network Address Transation (NAT) is + being used. + + + ack-port + N + Y + + When acknowledge is true, indicates the port to which the + acknowledgment should be sent. The adapter listens on this port for + acknowledgments. + + + ack-timeout + N + Y + + When acknowledge is true, indicates the time in milliseconds that the + adapter will wait for an acknowlegment. If an acknowlegment is not + received in time, the adapter will throw an exception. + + + min-acks-for- success + N + Y + + Defaults to 1. For multicast adapters, you can set this to a larger + value, requiring acknowlegments from multiple destinations. + + + check-length + N + Y + true, false + Whether or not a udp adapter includes a data length field in the + packet sent to the destination. + + + time-to-live + N + Y + + For multicast adapters, specifies the time to live attribute for + the MulticastSocket; controls the scope + of the multicasts. Refer to the Java API + documentation for more information. + + + using-nio + Y + N + true, false + Whether or not the tcp adapter is using NIO. Refer to the java.nio + package for more information. + + + using-direct-buffers + Y + N + true, false + When using NIO, whether or not the tcp adapter uses direct buffers. + Refer to java.nio.ByteBuffer documentation for + more information. + + + message-format + Y + N + length-header, stx-etx, crlf, custom + The formatting that the tcp adapter uses so the receiver can demarcate + messages. Defaults to length-header. + See the discussion above for details about each format. + + + custom-socket- writer-class-name + Y + N + Subclass of TcpNetSocket- Writer or TcpNioSocket- Writer + When message-format is 'custom' the name of the class that + implements the custom format. Must be a subclass of the TcpNxxSocketWriter, + depending on whether using-nio is false or true. + + + so-timeout + Y + Y + + See java.net.Socket and java.net.DatagramSocket + setSoTimeout() methods for more information. + + + so-send-buffer-size + Y + Y + + See java.net.Socket and java.net.DatagramSocket + setSendBufferSize() methods for more information. + + + so-receive-buffer- size + N + Y + + Used for udp acknowlegment packets. See java.net.DatagramSocket + setReceiveBufferSize() methods for more information. + + + so-keep-alive + Y + N + true, false + See java.net.Socket. setKeepAlive(). + + + so-linger + Y + N + + Sets linger to true with supplied value. + See java.net.Socket. setSoLinger(). + + + so-tcp-no-delay + Y + N + true, false + See java.net.Socket. setTcpNoDelay(). + + + so-traffic-class + Y + N + + See java.net.Socket. setTrafficClass(). + + + +
+ + IP Inbound Channel Adapter Attributes + + + + + + + + + + Attribute Name + TCP? + UDP? + Allowed Values + Attribute Description + + + + + protocol + Y + Y + tcp, udp + Determines whether the adapter uses TCP or UDP, over IP. + + + port + Y + Y + + The port on which the adapter listens. + + + multicast + N + Y + true, false + Whether or not the udp adapter uses multicast. + + + multicast-address + N + Y + + When multicast is true, the multicast address to which the adapter + joins. + + + pool-size + Y + Y + + Specifies the concurrency. For udp, specifies how many packets can + be handled concurrently. For tcp, not using nio, specifies the + number of concurrent connections supported by the adapter. For tcp, + using nio, specifies the number of tcp fragments that are concurrently + reassembled into complete messages. + + + receive-buffer-size + Y + Y + + For udp, the size of the buffer used to receive DatagramPackets. + Usually set to the MTU size. If a smaller buffer is used than the + size of the sent packet, truncation can occur. This can be detected + by means of the check-length attribute.For tcp, the size of the + buffer used to reassemble incoming messages. Effectively the maximum + message size that can be received. + + + check-length + N + Y + true, false + Whether or not a udp adapter expects a data length field in the + packet received. Used to detect packet truncation. + + + using-nio + Y + N + true, false + Whether or not the tcp adapter is using NIO. Refer to the java.nio + package for more information. + + + using-direct-buffers + Y + N + true, false + When using NIO, whether or not the tcp adapter uses direct buffers. + Refer to java.nio.ByteBuffer documentation for more information. + + + message-format + Y + N + length-header, stx-etx, crlf, custom + The formatting that the tcp adapter uses so the adapter can demarcate + messages. Defaults to length-header. + See the discussion above for details about each format. + + + custom-socket- reader-class-name + Y + N + Subclass of TcpNetSocket- Reader or TcpNioSocket- Reader + When message-format is 'custom' the name of the class that + implements the custom format. Must be a subclass of the TcpNxxSocketReader, + depending on whether using-nio is false or true. + + + so-timeout + Y + Y + + See java.net.Socket and java.net.DatagramSocket + setSoTimeout() methods for more information. + + + so-send-buffer-size + N + Y + + Used for udp acknowlegment packets. See java.net.DatagramSocket + setSendBufferSize() methods for more information. + + + so-receive-buffer- size + Y + Y + + See java.net.Socket and java.net.DatagramSocket + setReceiveBufferSize() for more information. + + + so-keep-alive + Y + N + true, false + See java.net.Socket. setKeepAlive(). + + + +
+ + TCP Inbound Gateway Attributes + + + + + + + + Attribute Name + Allowed Values + Attribute Description + + + + + port + + The port on which the gateway listens. + + + pool-size + + Specifies the number of concurrent connections supported + by the gateway. + + + receive-buffer-size + + The size of the + buffer used to reassemble incoming messages. Effectively the maximum + message size that can be received. + + + message-format + length-header, stx-etx, crlf, custom + The formatting that the tcp gateway uses for demarcating + incoming requests and formatting responses. Defaults to length-header. + See the discussion above for details about each format. + + + custom-socket- reader-class-name + Subclass of TcpNetSocket- Reader + When message-format is 'custom' the name of the class that + implements the custom format. Must be a subclass of the + TcpNetSocketReader. + + + custom-socket- writer-class-name + Subclass of TcpNetSocket- Writer + When message-format is 'custom' the name of the class that + implements the custom format. Must be a subclass of the + TcpNetSocketWriter. + + + so-timeout + + See java.net.Socket + setSoTimeout() for more information. + + + so-send-buffer-size + + See java.net.Socket + setSendBufferSize() methods for more information. + + + so-receive-buffer- size + + See java.net.Socket + setReceiveBufferSize() for more information. + + + so-keep-alive + true, false + See java.net.Socket. setKeepAlive(). + + + +
+ + TCP Outbound Gateway Attributes + + + + + + + + Attribute Name + Allowed Values + Attribute Description + + + + + host + + The host name or ip address of the destination. + + + port + + The port to which the gateway connects. + + + receive-buffer-size + + The size of the + buffer used to reassemble incoming messages. Effectively the maximum + message size that can be received. + + + message-format + length-header, stx-etx, crlf, custom + The formatting that the tcp gateway uses for formating + requests and demarcating + incoming responses. Defaults to length-header. + See the discussion above for details about each format. + + + custom-socket- reader-class-name + Subclass of TcpNetSocket- Reader + When message-format is 'custom' the name of the class that + implements the custom format. Must be a subclass of the + TcpNetSocketReader. + + + custom-socket- writer-class-name + Subclass of TcpNetSocket- Writer + When message-format is 'custom' the name of the class that + implements the custom format. Must be a subclass of the + TcpNetSocketWriter. + + + so-timeout + + See java.net.Socket + setSoTimeout() for more information. + + + so-send-buffer-size + + See java.net.Socket + setSendBufferSize() methods for more information. + + + so-receive-buffer- size + + See java.net.Socket + setReceiveBufferSize() for more information. + + + so-keep-alive + true, false + See java.net.Socket. setKeepAlive(). + + + +
+ +
+ diff --git a/spring-integration-reference/src/jms.xml b/spring-integration-reference/src/jms.xml new file mode 100644 index 0000000000..6519b0676d --- /dev/null +++ b/spring-integration-reference/src/jms.xml @@ -0,0 +1,261 @@ + + + + JMS Support + + Spring Integration provides Channel Adapters for receiving and sending JMS messages. There are actually two + JMS-based inbound Channel Adapters. The first uses Spring's JmsTemplate to receive based on + a polling period. The second is "message-driven" and relies upon a Spring MessageListener container. There is also + an outbound Channel Adapter which uses the JmsTemplate to convert and send a JMS Message on + demand. + + + Whereas the JMS Channel Adapters are intended for unidirectional Messaging (send-only or receive-only), Spring + Integration also provides inbound and outbound JMS Gateways for request/reply operations. The inbound gateway + relies on one of Spring's MessageListener container implementations for Message-driven reception that is also + capable of sending a return value to the "reply-to" Destination as provided by the received Message. The outbound + Gateway sends a JMS Message to a "request-destination" and then receives a reply Message. The "reply-destination" + reference (or "reply-destination-name") can be configured explicitly or else the outbound gateway will use a + JMS TemporaryQueue. + + +
+ Inbound Channel Adapter + + The inbound Channel Adapter requires a reference to either a single JmsTemplate + instance or both ConnectionFactory and Destination + (a 'destinationName' can be provided in place of the 'destination' reference). The following example defines an + inbound Channel Adapter with a Destination reference. + + + + + ]]> + + Notice from the configuration that the inbound-channel-adapter is a Polling Consumer. That means that + it invokes receive() when triggered. This should only be used in situations where polling is done relatively + infrequently and timeliness is not important. For all other situations (a vast majority of JMS-based use-cases), + the message-driven-channel-adapter described below is a better option. + + + All of the JMS adapters that require a reference to the ConnectionFactory will automatically look for + a bean named "connectionFactory" by default. That is why you don't see a "connection-factory" attribute + in many of the examples. However, if your JMS ConnectionFactory has a different bean name, then you will + need to provide that attribute. + + + + If 'extract-payload' is set to true (which is the default), the received JMS Message will be passed through + the MessageConverter. When relying on the default SimpleMessageConverter, this means that the resulting Spring + Integration Message will have the JMS Message's body as its payload. A JMS TextMessage will produce a + String-based payload, a JMS BytesMessage will produce a byte array payload, and a JMS ObjectMessage's + Serializable instance will become the Spring Integration Message's payload. If instead you prefer to have + the raw JMS Message as the Spring Integration Message's payload, then set 'extract-payload' to false. + + + + + ]]> + +
+ +
+ Message-Driven Channel Adapter + + The "message-driven-channel-adapter" requires a reference to either an instance of a Spring MessageListener + container (any subclass of AbstractMessageListenerContainer) or both + ConnectionFactory and Destination + (a 'destinationName' can be provided in place of the 'destination' reference). The following example defines a + message-driven Channel Adapter with a Destination reference. + ]]> + + The Message-Driven adapter also accepts several properties that pertain to the MessageListener container. + These values are only considered if you do not provide an actual 'container' reference. In that case, + an instance of DefaultMessageListenerContainer will be created and configured based on these properties. + For example, you can specify the "transaction-manager" reference, the "concurrent-consumers" value, and + several other property references and values. Refer to the JavaDoc and Spring Integration's JMS Schema + (spring-integration-jms-1.0.xsd) for more detail. + + + + The 'extract-payload' property has the same effect as described above, and once again its default value + is 'true'. The poller sub-element is not applicable for a message-driven + Channel Adapter, as it will be actively invoked. For most usage scenarios, the message-driven approach is better since the Messages will + be passed along to the MessageChannel as soon as they are received from the underlying + JMS consumer. + +
+ +
+ Outbound Channel Adapter + + The JmsSendingMessageHandler implements the MessageHandler + interface and is capable of converting Spring Integration Messages to JMS messages + and then sending to a JMS destination. It requires either a 'jmsTemplate' reference or both 'connectionFactory' and + 'destination' references (again, the 'destinationName' may be provided in place of the 'destination'). As with the + inbound Channel Adapter, the easiest way to configure this adapter is with the namespace support. The following + configuration will produce an adapter that receives Spring Integration Messages from the "exampleChannel" and then + converts those into JMS Messages and sends them to the JMS Destination reference whose bean name is "outQueue". + ]]> + + + As with the inbound Channel Adapters, there is an 'extract-payload' property. However, the meaning is reversed + for the outbound adapter. Rather than applying to the JMS Message, the boolean property applies to the Spring + Integration Message payload. In other words, the decision is whether to pass the Spring Integration Message + itself as the JMS Message body or whether to pass the Spring Integration Message's + payload as the JMS Message body. The default value is once again 'true'. Therefore, if you pass a Spring + Integration Message whose payload is a String, a JMS TextMessage will be created. If on the other hand you + want to send the actual Spring Integration Message to another system via JMS, then simply set this to 'false'. + + Regardless of the boolean value for payload extraction, the Spring Integration MessageHeaders will map to + JMS properties as long as you are relying on the default converter or provide a reference to another + instance of HeaderMappingMessageConverter (the same holds true for 'inbound' adapters except that in + those cases, it's the JMS properties mapping to Spring Integration MessageHeaders). + + +
+ +
+ Inbound Gateway + + Spring Integration's message-driven JMS inbound-gateway delegates to a + MessageListener container, supports dynamically adjusting concurrent consumers, + and can also handle replies. The inbound gateway requires references to a + ConnectionFactory, and a request Destination (or + 'requestDestinationName'). The following example defines a JMS "inbound-gateway" that receives from the JMS + queue referenced by the bean id "inQueue" and sends to the Spring Integration channel named "exampleChannel". + ]]> + + + Since the gateways provide request/reply behavior instead of unidirectional send or + receive, they also have two distinct properties for the "payload extraction" (as discussed above for the + Channel Adapters' 'extract-payload' setting). For an inbound-gateway, the 'extract-request-payload' property + determines whether the received JMS Message body will be extracted. If 'false', the JMS Message itself will + become the Spring Integration Message payload. The default is 'true'. + + + Similarly, for an inbound-gateway the 'extract-reply-payload' property applies to the Spring Integration Message + that is going to be converted into a reply JMS Message. If you want to pass the whole Spring Integration Message + (as the body of a JMS ObjectMessage) then set this to 'false'. By default, it is also 'true' such that the Spring + Integration Message payload will be converted into a JMS Message (e.g. String payload + becomes a JMS TextMessage). + +
+ +
+ Outbound Gateway + + The outbound Gateway creates JMS Messages from Spring Integration Messages and then sends to a + 'request-destination'. It will then handle the JMS reply Message either by using a selector to + receive from the 'reply-destination' that you configure, or if no 'reply-destination' is provided, + it will create JMS TemporaryQueues. Notice that the "reply-channel" is also provided. + ]]> + + + The 'outbound-gateway' payload extraction properties are inversely related to those of the + 'inbound-gateway' (see the discussion above). That means that the 'extract-request-payload' property value + applies to the Spring Integration Message that is being converted into a JMS Message to be + sent as a request, and the 'extract-reply-payload' property value applies to the + JMS Message that is received as a reply and then converted into a Spring Integration + Message to be subsequently sent to the 'reply-channel' as shown in the example configuration above. + + For all of these JMS adapters, you can also specify your own "message-converter" reference. Simply provide the + bean name of an instance of MessageConverter that is available within the same + ApplicationContext. Note, however, that when you provide your own MessageConverter instance, it will still + be wrapped within the HeaderMappingMessageConverter. This means that the 'extract-request-payload' + and 'extract-reply-payload' properties may effect what actual objects are passed to your converter. The + HeaderMappingMessageConverter itself simply delegates to a target MessageConverter while also mapping the + Spring Integration MessageHeaders to JMS Message properties and vice-versa. + + +
+ +
+ JMS Backed Message Channels + + The Channel Adapters and Gateways featured above are all intended for applications that are integrating + with other external systems. The inbound options assume that some other system is sending JMS Messages + to the JMS Destination and the outbound options assume that some other system is receiving from the + Destination. The other system may or may not be a Spring Integration application. Of course, when sending + the Spring Integration Message instance as the body of the JMS Message itself (with the 'extract-payload' + value set to false), it is assumed that the other system is based on Spring Integration. However, + that is by no means a requirement. That flexibility is one of the benefits of using a Message-based + integration option with the abstraction of "channels" or Destinations in the case of JMS. + + + There are cases where both the producer and consumer for a given JMS Destination are intended to be + part of the same application, running within the same process. This could be accomplished by using a + pair of inbound and outbound Channel Adapters. The problem with that approach is that two adapters are + required even though conceptually the goal is to have a single Message Channel. A better option is + supported as of Spring Integration version 2.0. Now it is possible to define a single "channel" when + using the JMS namespace. + ]]> + + + The channel in the above example will behave much like a normal <channel/> element from the main + Spring Integration namespace. It can be referenced by both "input-channel" and "output-channel" attributes + of any endpoint. The difference is that this channel is backed by a JMS Queue instance named "exampleQueue". + This means that asynchronous messaging is possible between the producing and consuming endpoints, but + unlike the simpler asynchronous Message Channels created by adding a <queue/> sub-element within a + non-JMS <channel/> element, the Messages are not just stored in an in-memory queue. Instead those + Messages are passed within a JMS Message body, and the full power of the underlying JMS provider is then + available for that channel. Probably the most common rationale for using this alternative would be to + take advantage of the persistence made available by the store and forward approach + of JMS messaging. If configured properly, the JMS-backed Message Channel also supports transactions. + In other words, a producer would not actually write to a transactional JMS-backed channel if its send + operation is part of a transaction that rolls back. Likewise, a consumer would not physically remove a + JMS Message from the channel if the reception of that Message is part of a transaction that rolls back. + Note that the producer and consumer transactions are separate in such a scenario. This is significantly + different than the propagation of a transactional context across the simple, synchronous <channel/> + element that has no <queue/> sub-element. + + + Since the example above is referencing a JMS Queue instance, it will act as a point-to-point channel. If + on the other hand, publish/subscribe behavior is needed, then a separate element can be used, and a JMS + Topic can be referenced instead. + ]]> + + + For either type of JMS-backed channel, the name of the destination may be provided instead of a reference. + + + ]]> + + + In the examples above, the Destination names would be resolved by Spring's default + DynamicDestinationResolver implementation, but any implementation of the + DestinationResolver interface could be provided. Also, the JMS + ConnectionFactory is a required property of the channel, but by default + the expected bean name would be "connectionFactory". The example below provides both a custom instance + for resolution of the JMS Destination names and a different name for the ConnectionFactory. + ]]> + +
+ +
+ JMS Samples + + To experiment with these JMS adapters, check out the samples available within the "samples/jms" directory in + the distribution. There are two samples included. One provides inbound and outbound Channel Adapters, and the + other provides inbound and outbound Gateways. They are configured to run with an embedded ActiveMQ process, but + the "common.xml" file can easily be modified to support either a different JMS provider or a standalone + ActiveMQ process. In other words, you can split the configuration so that the inbound and outbound adapters are + running in separate JVMs. If you have ActiveMQ installed, simply modify the "brokerURL" property within the + configuration to use "tcp://localhost:61616" for example (instead of "vm://localhost"). Both of the samples + accept input via stdin and then echo back to stdout. Look at the configuration to see how these messages are + routed over JMS. + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/jmx.xml b/spring-integration-reference/src/jmx.xml new file mode 100644 index 0000000000..aa44668380 --- /dev/null +++ b/spring-integration-reference/src/jmx.xml @@ -0,0 +1,175 @@ + + + + JMX Support + + Spring Integration provides Channel Adapters for receiving and publishing JMX Notifications. + There is also an inbound Channel Adapter for polling JMX MBean attribute values, and an + outbound Channel Adapter for invoking JMX MBean operations. + + +
+ Notification Listening Channel Adapter + + The Notification-listening Channel Adapter requires a JMX ObjectName for the MBean that publishes + Notifications to which this listener should be registered. A very simple configuration might look like this: + +]]> + + The notification-listening-channel-adapter registers with an MBeanServer at startup, and + the default bean name is "mbeanServer" which happens to be the same bean name generated + when using Spring's <context:mbean-server/> element. If you need to use a different + name be sure to include the "mbean-server" attribute. + + The adapter can also accept a reference to a NotificationFilter and a "handback" Object + to provide some context that is passed back with each Notification. Both of those attributes + are optional. Extending the above example to include those attributes as well as an explicit + MBeanServer bean name would produce the following: + +]]> + Since the notification-listening adapter is registered with the MBeanServer directly, it is + event-driven and does not require any poller configuration. + +
+ +
+ Notification Publishing Channel Adapter + + The Notification-publishing Channel Adapter is relatively simple. It only requires a + JMX ObjectName in its configuration as shown below. + + + +]]> + It does also require that an MBeanExporter be present in the context. That is why the + <context:mbean-export/> element is shown above as well. + + + When Messages are sent to the channel for this adapter, the Notification + is created from the Message content. If the payload is a String it will be + passed as the "message" text for the Notification. Any other payload type + will be passed as the "userData" of the Notification. + + + JMX Notifications also have a "type", and it should be a dot-delimited String. + There are two ways to provide the type. Precedence will always be given to a + Message header value associated with the JmxHeaders.NOTIFICATION_TYPE key. + On the other hand, you can rely on a fallback "default-notification-type" + attribute provided in the configuration. + + + +]]> + +
+ +
+ Attribute Polling Channel Adapter + + The attribute polling adapter is useful when you have a requirement to periodically + check on some value that is available through an MBean as a managed attribute. The + poller can be configured in the same way as any other polling adapter in Spring + Integration (or it's possible to rely on the default poller). The "object-name" + and "attribute-name" are required. An MBeanServer reference is also required, but + it will automatically check for a bean named "mbeanServer" by default just like + the notification-listening-channel-adapter described above. + + + + + +]]> + +
+ +
+ Operation Invoking Channel Adapter + + The operation-invoking-channel-adapter enables Message-driven invocation of + any managed operation exposed by an MBean. Each invocation requires the + operation name to be invoked and the ObjectName of the target MBean. In each + case, the adapter will first check for header values on the Message itself. + The keys for these headers are defined as JmxHeaders.OPERATION_NAME and + JmxHeaders.OBJECT_NAME, respectively. If relying on those Message headers, + the configuration is trivial. + +]]> + That adapter only needs to be able to discover the "mbeanServer" bean. If + a different bean name is required, then provide the "mbean-server" attribute + with a reference. + + + The payload of the Message will be mapped to the parameters of the operation, if any. + A Map-typed payload with String keys is treated as name/value pairs whereas a List or + array would be passed as a simple argument list (with no explicit parameter names). + If the operation requires a single parameter value, then the payload can represent + that single value, and if the operation requires no parameters, then the payload + would be ignored. + + + Similar to the behavior described above for the Notification type resoltion, + the operation-invoking-channel-adapter will also fallback to default values if + provided: + +]]> + If you want to expose a channel for a single common operation to be invoked + by Messages that need not contain headers, then that option works well. + +
+ +
+ Control Bus + + Spring Integration components themselves may be exposed as MBeans when the Control Bus + is configured. As described in (EIP), + the idea behind the Control Bus is that the same messaging system can be used for monitoring + and managing the components within the framework as is used for "application-level" messaging. + In Spring Integration we build upon the adapters described above so that it's possible to + send Messages as a means of invoking exposed operations. Internally, the Control Bus uses + a Spring MBeanExporter instance to expose the various endpoints and channels. To create + an instance of the Control Bus, define a bean and provide a reference to an MBeanServer + and a domain name (we will be providing namespace support). The domain can be left out + in which case the default domain is "org.springframework.integration". + + + + + + + + +]]> + + + The Control Bus has an "operationChannel" that can be accessed for invoking operations + on the MBeans that it has exported. This will also be covered by namespace support soon + to make it easier to configure references to that channel for other producers. We will + likely add some other channels for notifications and attribute polling as well. + + + The Control Bus functionality is a work in progress. At this time, one can perform some + basic monitoring of Message Channels and/or invoke Lifecycle operations (start/stop) on + Message Endpoints. Now that the foundation is available, however, we will be able to extend + the attributes and operations that are being exposed. + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/mail.xml b/spring-integration-reference/src/mail.xml new file mode 100644 index 0000000000..f0c7f8cd9a --- /dev/null +++ b/spring-integration-reference/src/mail.xml @@ -0,0 +1,121 @@ + + + + Mail Support + +
+ Mail-Sending Channel Adapter + + Spring Integration provides support for outbound email with the + MailSendingMessageHandler. It delegates to a configured instance of Spring's + JavaMailSender: + JavaMailSender mailSender = (JavaMailSender) context.getBean("mailSender"); + + MailSendingMessageHandler mailSendingHandler = new MailSendingMessageHandler(mailSender); + MailSendingMessageHandler has various mapping strategies that use Spring's + MailMessage abstraction. If the received Message's payload is already + a MailMessage instance, it will be sent directly. + Therefore, it is generally recommended to precede this + consumer with a Transformer for non-trivial MailMessage construction requirements. However, a few simple + Message mapping strategies are supported out-of-the-box. For example, if the message payload is a byte array, + then that will be mapped to an attachment. For simple text-based emails, you can provide a String-based + Message payload. In that case, a MailMessage will be created with that String as the text content. If you + are working with a Message payload type whose toString() method returns appropriate mail text content, then + consider adding Spring Integration's ObjectToStringTransformer prior to the outbound + Mail adapter (see the example within for more detail). + + + The outbound MailMessage may also be configured with certain values from the + MessageHeaders. If available, values will be mapped to the outbound mail's + properties, such as the recipients (TO, CC, and BCC), the from/reply-to, and the subject. The header names are + defined by the following constants: + MailHeaders.SUBJECT + MailHeaders.TO + MailHeaders.CC + MailHeaders.BCC + MailHeaders.FROM + MailHeaders.REPLY_TO + + + MailHeaders also allows you to override corresponding MailMessage values. + For example: If MailMessage.to is set to 'foo@bar.com' and MailHeaders.TO + Message header is provided it will take precedence and override the corresponding value in MailMessage + +
+ +
+ Mail-Receiving Channel Adapter + + Spring Integration also provides support for inbound email with the + MailReceivingMessageSource. It delegates to a configured instance of Spring + Integration's own MailReceiver interface, and there are two implementations: + Pop3MailReceiver and ImapMailReceiver. The easiest way to + instantiate either of these is by passing the 'uri' for a Mail store to the receiver's constructor. For example: + + + + Another option for receiving mail is the IMAP "idle" command (if supported by the mail server you are using). + Spring Integration provides the ImapIdleChannelAdapter which is itself a Message-producing + endpoint. It delegates to an instance of the ImapMailReceiver but enables asynchronous + reception of Mail Messages. There are examples in the next section of configuring both types of inbound Channel + Adapter with Spring Integration's namespace support in the 'mail' schema. + +
+ +
+ Mail Namespace Support + + Spring Integration provides a namespace for mail-related configuration. To use it, configure the following schema + locations. +]]> + + + To configure an outbound Channel Adapter, provide the channel to receive from, and the MailSender: + ]]> + Alternatively, provide the host, username, and password: + ]]> + + Keep in mind, as with any outbound Channel Adapter, if the referenced channel is a PollableChannel, a + <poller> sub-element should be provided with either an interval-trigger or cron-trigger. + + + + To configure an inbound Channel Adapter, you have the choice between polling or event-driven (assuming your + mail server supports IMAP IDLE - if not, then polling is the only option). A polling Channel Adapter simply + requires the store URI and the channel to send inbound Messages to. The URI may begin with "pop3" or "imap": + + + + + ]]> + If you do have IMAP idle support, then you may want to configure the "imap-idle-channel-adapter" element instead. + Since the "idle" command enables event-driven notifications, no poller is necessary for this adapter. It will + send a Message to the specified channel as soon as it receives the notification that new mail is available: + ]]> + + + When using the namespace support, a header-enricher Message Transformer is also available. + This simplifies the application of the headers mentioned above to any Message prior to sending to the + Mail-sending Channel Adapter. + ]]> + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/message-publishing.xml b/spring-integration-reference/src/message-publishing.xml new file mode 100644 index 0000000000..c0edf65fdd --- /dev/null +++ b/spring-integration-reference/src/message-publishing.xml @@ -0,0 +1,151 @@ + + + + Message Publishing + + Message Publishing feature will allow you to send a message as a result of method invocation. For example; Imagine you + have a component and every time the state of this components changes you would like to get notified. The easiest + way to send notification would be to send a message to a dedicated channel, but how would you connect the method invocation that + changes the state of the object to a message sending process and what should be the structure of the + message? Message Publishing feature will allow you to do just that. + +
+ Message Publishing Configuration + + Spring Integration provides two approaches - XML and Annotation. + +
+ Annotation-based approach via @Publisher annotation + + Annotation bassed approach allows you to annotate any method with @Publisher annotation and + provide configuration attributes which will dictate the structure of a Message. Invocation of such + method will be proxied through PublisherAnnotationAdvisor which will + construct a Message and send it to a channel. + + + Internally PublisherAnnotationAdvisor uses Spring 3.0 Expression Language support giving you + the flexibility and control over the structure of a Message it will build. + + + PublisherAnnotationAdvisor defines and binds the following variables: + + + #return - will bind to a return value allowing you to reference it or its + attributes (e.g., #return.foo where 'foo' is an attribute of the object bound to + #return) + + + #exception - will bind to an exception if one is thrown. + + + #[parameName] - will be dynamically constructed pointing to the method parameter + names (e.g., #fname as in the above method) + + + + +@Publisher(value="#return", channel="testChannel", headers="bar='123',fname=#fname") +public String setName(String fname, String lname){ + return fname + " " + lname; +} + + + In the above example the Message will be constructed and its structure will be as follows: + + + Message payload - will be of type String and contain the value returned by the method. + + + Message headers will be 'bar' with value of "123" and 'fname' with value of 'fname' parameter of the method. + + + + + As with any other annotation you will need to register PublisherAnnotationBeanPostProcessor + <bean class="org.springframework.integration.aop.PublisherAnnotationBeanPostProcessor"/> + +
+
+ XML-based approach via <publisher> element + + XML-based approach allows you to configure Message Publishing via AOP-based configuration and + simple namespace-based configuration of MessagePublishingInterceptor. + It certainly has certain benefits over annotation based approach since it + allows you to use AOP pointcut expressions, thus possibly intercepting multiple methods at once or + intercepting and publishing methods to which you don't have a source code. + + + To configure Message Publishing via XML all you need is the following two things: + + + Provide configuration for MessagePublishingInterceptor + via <publisher> XML element + + + Provide AOP configuration to apply MessagePublishingInterceptor + + + + + +<beans:bean id="testBean" class="org.foo.bar.TestBean" /> +<aop:config> + <aop:advisor advice-ref="interceptor" pointcut="bean(testBean)" /> +</aop:config> + +<publisher id="interceptor" default-channel="defaultChannel"> + <method pattern="echo" payload="'Echoing: ' + #return" headers="foo='bar'" channel="echoChannel"/> + <method pattern="echoDef*" payload="#return"/> + <method pattern="foo*"/> +</publisher> + + + + As you can see <publisher> uses the same variables as + PublisherAnnotationAdvisor to utilize the power of Spring 3.0 Expression Langage. + + + In the above example the execution of echo method of a testBean will + rander the Message with the following structure: + + + Message payload - will be of type String and value of "Echoing: [value]" where value is the value + returned by an executed method. + + + Message headers will be 'foo' with value of "bar". + + + Message will be sent to echoChannel. + + + + + In the second method mapping the execution of any method that begins with echoDef of testBean will result in the + Message with the following structure. + + + Message payload - will be the value + returned by an executed method. + + + Since channel attriute is not provided, the Message will be sent to the + defaultChannel defined by the publisher. + + + + + The third mapping is almost identical to the previous (with the exceptipon of method pattern), + since the return value will be mapped to the Message paylad by default if nothing else is specifued. + + + For a simple maping rules you can rely on publisher defaults. For example: + +<publisher id="anotherInterceptor"/> + + This will map the return value of every method that matches the pointcut expression to a payload and will be sent to a default-channel. + If the defaultChannelis not specified (as above) the messages will be sent to nullChannel + +
+
+ \ No newline at end of file diff --git a/spring-integration-reference/src/message.xml b/spring-integration-reference/src/message.xml new file mode 100644 index 0000000000..ad06c9dc3d --- /dev/null +++ b/spring-integration-reference/src/message.xml @@ -0,0 +1,222 @@ + + + + Message Construction + + The Spring Integration Message is a generic container for data. Any object can + be provided as the payload, and each Message also includes headers containing + user-extensible properties as key-value pairs. + + +
+ The Message Interface + Here is the definition of the Message interface: + public interface Message<T> { + + T getPayload(); + + MessageHeaders getHeaders(); + +} + + + The Message is obviously a very important part of the API. By encapsulating the + data in a generic wrapper, the messaging system can pass it around without any knowledge of the data's type. As + an application evolves to support new types, or when the types themselves are modified and/or extended, the + messaging system will not be affected by such changes. On the other hand, when some component in the messaging + system does require access to information about the Message, + such metadata can typically be stored to and retrieved from the metadata in the Message Headers. + +
+ +
+ Message Headers + + Just as Spring Integration allows any Object to be used as the payload of a Message, it also supports any Object + types as header values. In fact, the MessageHeaders class implements the + java.util.Map interface: + public final class MessageHeaders implements Map<String, Object>, Serializable { + ... +} + + Even though the MessageHeaders implements Map, it is effectively a read-only implementation. Any attempt to + put a value in the Map will result in an UnsupportedOperationException. + The same applies for remove and clear. Since Messages may be passed to + multiple consumers, the structure of the Map cannot be modified. Likewise, the Message's payload Object can not + be set after the initial creation. However, the mutability of the header values themselves + (or the payload Object) is intentionally left as a decision for the framework user. + + + + As an implementation of Map, the headers can obviously be retrieved by calling get(..) + with the name of the header. Alternatively, you can provide the expected Class as an + additional parameter. Even better, when retrieving one of the pre-defined values, convenient getters are + available. Here is an example of each of these three options: + Object someValue = message.getHeaders().get("someKey"); + + CustomerId customerId = message.getHeaders().get("customerId", CustomerId.class); + + Long timestamp = message.getHeaders().getTimestamp(); + + + + The following Message headers are pre-defined: + + Pre-defined Message Headers + + + + + Header Name + Header Type + + + + + ID + java.util.UUID + + + TIMESTAMP + java.lang.Long + + + EXPIRATION_DATE + java.lang.Long + + + CORRELATION_ID + java.lang.Object + + + REPLY_CHANNEL + java.lang.Object (can be a String or MessageChannel) + + + ERROR_CHANNEL + java.lang.Object (can be a String or MessageChannel) + + + SEQUENCE_NUMBER + java.lang.Integer + + + SEQUENCE_SIZE + java.lang.Integer + + + PRIORITY + MessagePriority (an enum) + + + +
+ + + Many inbound and outbound adapter implementations will also provide and/or expect certain headers, and additional + user-defined headers can also be configured. + +
+ +
+ Message Implementations + + The base implementation of the Message interface is + GenericMessage<T>, and it provides two constructors: + new GenericMessage<T>(T payload); + +new GenericMessage<T>(T payload, Map<String, Object> headers) + When a Message is created, a random unique id will be generated. The constructor that accepts a Map of headers + will copy the provided headers to the newly created Message. + + + There are also two convenient subclasses available: StringMessage and + ErrorMessage. The former accepts a String as its payload: + StringMessage message = new StringMessage("hello world"); + +String s = message.getPayload(); + And, the latter accepts any Throwable object as its payload: + ErrorMessage message = new ErrorMessage(someThrowable); + +Throwable t = message.getPayload(); + Notice that these implementations take advantage of the fact that the GenericMessage + base class is parameterized. Therefore, as shown in both examples, no casting is necessary when retrieving + the Message payload Object. + +
+ +
+ The MessageBuilder Helper Class + + You may notice that the Message interface defines retrieval methods for its payload and headers but no setters. + The reason for this is that a Message cannot be modified after its initial creation. Therefore, when a Message + instance is sent to multiple consumers (e.g. through a Publish Subscribe Channel), if one of those consumers + needs to send a reply with a different payload type, it will need to create a new Message. As a result, the + other consumers are not affected by those changes. Keep in mind, that multiple consumers may access the same + payload instance or header value, and whether such an instance is itself immutable is a decision left to the + developer. In other words, the contract for Messages is similar to that of an + unmodifiable Collection, and the MessageHeaders' map further exemplifies that; even though + the MessageHeaders class implements java.util.Map, any attempt to invoke a + put operation (or 'remove' or 'clear') on the MessageHeaders will result in an + UnsupportedOperationException. + + + Rather than requiring the creation and population of a Map to pass into the GenericMessage constructor, Spring + Integration does provide a far more convenient way to construct Messages: MessageBuilder. + The MessageBuilder provides two factory methods for creating Messages from either an existing Message or with a + payload Object. When building from an existing Message, the headers and payload of that + Message will be copied to the new Message: + Message<String> message1 = MessageBuilder.withPayload("test") + .setHeader("foo", "bar") + .build(); + +Message<String> message2 = MessageBuilder.fromMessage(message1).build(); + +assertEquals("test", message2.getPayload()); +assertEquals("bar", message2.getHeaders().get("foo")); + + + If you need to create a Message with a new payload but still want to copy the + headers from an existing Message, you can use one of the 'copy' methods. + Message<String> message3 = MessageBuilder.withPayload("test3") + .copyHeaders(message1.getHeaders()) + .build(); + +Message<String> message4 = MessageBuilder.withPayload("test4") + .setHeader("foo", 123) + .copyHeadersIfAbsent(message1.getHeaders()) + .build(); + +assertEquals("bar", message3.getHeaders().get("foo")); +assertEquals(123, message4.getHeaders().get("foo")); + Notice that the copyHeadersIfAbsent does not overwrite existing values. Also, in the + second example above, you can see how to set any user-defined header with setHeader. + Finally, there are set methods available for the predefined headers as well as a non-destructive method for + setting any header (MessageHeaders also defines constants for the pre-defined header names). + Message<Integer> importantMessage = MessageBuilder.withPayload(99) + .setPriority(MessagePriority.HIGHEST) + .build(); + +assertEquals(MessagePriority.HIGHEST, importantMessage.getHeaders().getPriority()); + +Message<Integer> anotherMessage = MessageBuilder.fromMessage(importantMessage) + .setHeaderIfAbsent(MessageHeaders.PRIORITY, MessagePriority.LOW) + .build(); + +assertEquals(MessagePriority.HIGHEST, anotherMessage.getHeaders().getPriority()); + + + + The MessagePriority is only considered when using a PriorityChannel + (as described in the next chapter). It is defined as an enum with five possible values: + public enum MessagePriority { + HIGHEST, + HIGH, + NORMAL, + LOW, + LOWEST +} + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/overview.xml b/spring-integration-reference/src/overview.xml new file mode 100644 index 0000000000..b3d8740834 --- /dev/null +++ b/spring-integration-reference/src/overview.xml @@ -0,0 +1,303 @@ + + + + Spring Integration Overview + +
+ Background + + One of the key themes of the Spring Framework is inversion of control. In its broadest + sense, this means that the framework handles responsibilities on behalf of the components that are managed within + its context. The components themselves are simplified since they are relieved of those responsibilities. For + example, dependency injection relieves the components of the responsibility of locating or + creating their dependencies. Likewise, aspect-oriented programming relieves business + components of generic cross-cutting concerns by modularizing them into reusable aspects. In each case, the end + result is a system that is easier to test, understand, maintain, and extend. + + + Furthermore, the Spring framework and portfolio provide a comprehensive programming model for building + enterprise applications. Developers benefit from the consistency of this model and especially the fact that it is + based upon well-established best practices such as programming to interfaces and favoring composition over + inheritance. Spring's simplified abstractions and powerful support libraries boost developer productivity while + simultaneously increasing the level of testability and portability. + + + Spring Integration is a new member of the Spring portfolio motivated by these same goals and principles. It + extends the Spring programming model into the messaging domain and builds upon Spring's existing enterprise + integration support to provide an even higher level of abstraction. It supports message-driven architectures + where inversion of control applies to runtime concerns, such as when certain business logic + should execute and where the response should be sent. It supports routing and transformation + of messages so that different transports and different data formats can be integrated without impacting + testability. In other words, the messaging and integration concerns are handled by the framework, so business + components are further isolated from the infrastructure and developers are relieved of complex integration + responsibilities. + + + As an extension of the Spring programming model, Spring Integration provides a wide variety of configuration + options including annotations, XML with namespace support, XML with generic "bean" elements, and of course direct + usage of the underlying API. That API is based upon well-defined strategy interfaces and non-invasive, delegating + adapters. Spring Integration's design is inspired by the recognition of a strong affinity between common patterns + within Spring and the well-known Enterprise Integration Patterns + as described in the book of the same name by Gregor Hohpe and Bobby Woolf (Addison Wesley, 2004). Developers who + have read that book should be immediately comfortable with the Spring Integration concepts and terminology. + +
+ +
+ Goals and Principles + Spring Integration is motivated by the following goals: + + + Provide a simple model for implementing complex enterprise integration solutions. + + + Facilitate asynchronous, message-driven behavior within a Spring-based application. + + + Promote intuitive, incremental adoption for existing Spring users. + + + + Spring Integration is guided by the following principles: + + + Components should be loosely coupled for modularity and testability. + + + The framework should enforce separation of concerns between business logic and + integration logic. + + + Extension points should be abstract in nature but within well-defined boundaries to promote + reuse and portability. + + + +
+ +
+ Main Components + + From the vertical perspective, a layered architecture facilitates separation of concerns, + and interface-based contracts between layers promote loose coupling. Spring-based applications are typically + designed this way, and the Spring framework and portfolio provide a strong foundation for following this best + practice for the full-stack of an enterprise application. Message-driven architectures add a + horizontal perspective, yet these same goals are still relevant. Just as "layered + architecture" is an extremely generic and abstract paradigm, messaging systems typically follow the similarly + abstract "pipes-and-filters" model. The "filters" represent any component that is capable of producing and/or + consuming messages, and the "pipes" transport the messages between filters so that the components themselves + remain loosely-coupled. It is important to note that these two high-level paradigms are not mutually exclusive. + The underlying messaging infrastructure that supports the "pipes" should still be encapsulated in a layer whose + contracts are defined as interfaces. Likewise, the "filters" themselves would typically be managed within a layer + that is logically above the application's service layer, interacting with those services through interfaces much + in the same way that a web-tier would. + + +
+ Message + + In Spring Integration, a Message is a generic wrapper for any Java object combined with metadata used by the + framework while handling that object. It consists of a payload and headers. The payload can be of any type and + the headers hold commonly required information such as id, timestamp, expiration, and return address. Headers + are also used for passing values to and from connected transports. For example, when creating a Message from a + received File, the file name may be stored in a header to be accessed by downstream components. Likewise, if a + Message's content is ultimately going to be sent by an outbound Mail adapter, the various properties (to, from, + cc, subject, etc.) may be configured as Message header values by an upstream component. Developers can also + store any arbitrary key-value pairs in the headers. + + + + + + +
+ +
+ Message Channel + + A Message Channel represents the "pipe" of a pipes-and-filters architecture. Producers send Messages to + a channel, and consumers receive Messages from a channel. The Message Channel therefore decouples the + messaging components, and also provides a convenient point for interception and monitoring of Messages. + + + + + + A Message Channel may follow either Point-to-Point or Publish/Subscribe semantics. With a Point-to-Point + channel, at most one consumer can receive each Message sent to the channel. Publish/Subscribe channels, on the + other hand, will attempt to broadcast each Message to all of its subscribers. Spring Integration supports + both of these. + + + Whereas "Point-to-Point" and "Publish/Subscribe" define the two options for how many + consumers will ultimately receive each Message, there is another important consideration: should the channel + buffer messages? In Spring Integration, Pollable Channels are capable of buffering + Messages within a queue. The advantage of buffering is that it allows for throttling the inbound Messages and + thereby prevents overloading a consumer. However, as the name suggests, this also adds some complexity, since a + consumer can only receive the Messages from such a channel if a poller is configured. On + the other hand, a consumer connected to a Subscribable Channel is simply Message-driven. + The variety of channel implementations available in Spring Integration will be discussed in detail in + . + +
+ +
+ Message Endpoint + + One of the primary goals of Spring Integration is to simplify the development of enterprise integration + solutions through inversion of control. This means that you should not have to implement + consumers and producers directly, and you should not even have to build Messages and invoke send or receive + operations on a Message Channel. Instead, you should be able to focus on your specific domain model with an + implementation based on plain Objects. Then, by providing declarative configuration, you can "connect" + your domain-specific code to the messaging infrastructure provided by Spring Integration. The components + responsible for these connections are Message Endpoints. This does not mean that you will necessarily connect + your existing application code directly. Any real-world enterprise integration solution will require some + amount of code focused upon integration concerns such as routing and + transformation. The important thing is to achieve separation of concerns between such + integration logic and business logic. In other words, as with the Model-View-Controller paradigm for web + applications, the goal should be to provide a thin but dedicated layer that translates inbound requests into + service layer invocations, and then translates service layer return values into outbound replies. The next + section will provide an overview of the Message Endpoint types that handle these responsibilities, and in + upcoming chapters, you will see how Spring Integration's declarative configuration options provide a + non-invasive way to use each of these. + +
+
+ +
+ Message Endpoints + + A Message Endpoint represents the "filter" of a pipes-and-filters architecture. As mentioned above, the + endpoint's primary role is to connect application code to the messaging framework and to do so in a non-invasive + manner. In other words, the application code should ideally have no awareness of the Message objects or the + Message Channels. This is similar to the role of a Controller in the MVC paradigm. Just as a Controller handles + HTTP requests, the Message Endpoint handles Messages. Just as Controllers are mapped to URL patterns, Message + Endpoints are mapped to Message Channels. The goal is the same in both cases: isolate application code from the + infrastructure. These concepts are discussed at length along with all of the patterns that follow in the + Enterprise Integration Patterns book. Here, we provide only a + high-level description of the main endpoint types supported by Spring Integration and their roles. The chapters + that follow will elaborate and provide sample code as well as configuration examples. + + +
+ Transformer + + A Message Transformer is responsible for converting a Message's content or structure and returning the modified + Message. Probably the most common type of transformer is one that converts the payload of the Message from one + format to another (e.g. from XML Document to java.lang.String). Similarly, a transformer may be used to add, + remove, or modify the Message's header values. + +
+ +
+ Filter + + A Message Filter determines whether a Message should be passed to an output channel at all. This simply + requires a boolean test method that may check for a particular payload content type, a property value, the + presence of a header, etc. If the Message is accepted, it is sent to the output channel, but if not it will be + dropped (or for a more severe implementation, an Exception could be thrown). Message Filters are often used in + conjunction with a Publish Subscribe channel, where multiple consumers may receive the same Message and use the + filter to narrow down the set of Messages to be processed based on some criteria. + + Be careful not to confuse the generic use of "filter" within the Pipes-and-Filters architectural pattern with + this specific endpoint type that selectively narrows down the Messages flowing between two channels. The + Pipes-and-Filters concept of "filter" matches more closely with Spring Integration's Message Endpoint: any + component that can be connected to Message Channel(s) in order to send and/or receive Messages. + + +
+ +
+ Router + + A Message Router is responsible for deciding what channel or channels should receive the Message next (if any). + Typically the decision is based upon the Message's content and/or metadata available in the Message Headers. + A Message Router is often used as a dynamic alternative to a statically configured output channel on + a Service Activator or other endpoint capable of sending reply Messages. Likewise, a Message Router provides a + proactive alternative to the reactive Message Filters used by multiple subscribers as described above. + + + + + + +
+ +
+ Splitter + + A Splitter is another type of Message Endpoint whose responsibility is to accept a Message from its input + channel, split that Message into multiple Messages, and then send each of those to its output channel. This + is typically used for dividing a "composite" payload object into a group of Messages containing the + sub-divided payloads. + +
+ +
+ Aggregator + + Basically a mirror-image of the Splitter, the Aggregator is a type of Message Endpoint that receives multiple + Messages and combines them into a single Message. In fact, Aggregators are often downstream consumers in a + pipeline that includes a Splitter. Technically, the Aggregator is more complex than a Splitter, because it + is required to maintain state (the Messages to-be-aggregated), to decide when the complete group of Messages + is available, and to timeout if necessary. Furthermore, in case of a timeout, the Aggregator needs to know + whether to send the partial results or to discard them to a separate channel. Spring Integration provides + a CompletionStrategy as well as configurable settings for timeout, whether + to send partial results upon timeout, and the discard channel. + +
+ +
+ Service Activator + + A Service Activator is a generic endpoint for connecting a service instance to the messaging system. The + input Message Channel must be configured, and if the service method to be invoked is capable of returning a + value, an output Message Channel may also be provided. + + The output channel is optional, since each Message may also provide its own 'Return Address' header. This + same rule applies for all consumer endpoints. + + The Service Activator invokes an operation on some service object to process the request Message, extracting + the request Message's payload and converting if necessary (if the method does not expect a Message-typed + parameter). Whenever the service object's method returns a value, that return value will likewise be converted + to a reply Message if necessary (if it's not already a Message). That reply Message is sent to the output + channel. If no output channel has been configured, then the reply will be sent to the channel specified in the + Message's "return address" if available. + + + + + + A request-reply "Service Activator" endpoint connects a target object's method to input and output + Message Channels. + + + +
+ +
+ Channel Adapter + + A Channel Adapter is an endpoint that connects a Message Channel to some other system or transport. Channel + Adapters may be either inbound or outbound. Typically, the Channel Adapter will do some mapping between the + Message and whatever object or resource is received-from or sent-to the other system (File, HTTP Request, JMS + Message, etc). Depending on the transport, the Channel Adapter may also populate or extract Message header + values. Spring Integration provides a number of Channel Adapters, and they will be described in upcoming + chapters. + + + + + An inbound "Channel Adapter" endpoint connects a source system to a MessageChannel. + + + + + + An outbound "Channel Adapter" endpoint connects a MessageChannel to a target system. + + +
+
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/resequencer.xml b/spring-integration-reference/src/resequencer.xml new file mode 100644 index 0000000000..8a59ea0b02 --- /dev/null +++ b/spring-integration-reference/src/resequencer.xml @@ -0,0 +1,109 @@ + + + + Resequencer + +
+ Introduction + + Related to the Aggregator, albeit different from a functional + standpoint, is the Resequencer. +
+ +
+ Functionality + + The Resequencer works in a similar way to the Aggregator, in the + sense that it uses the CORRELATION_ID to store messages in groups, the + difference being that the Resequencer does not process the messages in + any way. It simply releases them in the order of their SEQUENCE_NUMBER + header values. + + With respect to that, the user might opt to release all messages at + once (after the whole sequence, according to the SEQUENCE_SIZE, has been + released), or as soon as a valid sequence is available. +
+ +
+ Configuring a Resequencer with XML + + Configuring a resequencer requires only including the appropriate + element in XML. + + A sample resequencer configuration is shown below. + + <channel id="inputChannel"/> + +<channel id="outputChannel"/> + +<resequencer id="completelyDefinedResequencer" + input-channel="inputChannel" + output-channel="outputChannel" + discard-channel="discardChannel" + release-partial-sequences="true" + message-store="messageStore" + send-partial-result-on-expiry="true" + send-timeout="86420000" /> + + + + The id of the resequencer is + optional. + + + + The input channel of the resequencer. + Required. + + + + The channel where the resequencer will send the reordered + messages. Optional. + + + + The channel where the resequencer will send the messages that + timed out (if send-partial-result-on-timeout is + false). Optional. + + + + Whether to send out ordered sequences as soon as they are + available, or only after the whole message group arrives. + Optional (false by default). If this + flag is not specified (so a complete sequence is defined by the sequence + headers) then it can make sense to provide a custom Comparator + to be used to order the messages when sending + (use the XML attribute comparator to point to a bean + definition). If release-partial-sequences is true then + there is no way with a custom comparator to define a partial sequence. To + do that you would have to provide a release-strategy (also + a reference to another bean definition, either a POJO or a ReleaseStrategy). + + + + A reference to a MessageGroupStore that + can be used to store groups of messages under their + correlation key until they are + complete. Optional with default a + volatile in-memory store. + + + + Whether, upon the expiration of the group, the ordered group + should be sent out (even if some of the messages are missing). + Optional (false by default). + + + + The timeout for sending out messages. + Optional. + + + + + Since there is no custom behavior to be implemented in Java classes for resequencers, there is no annotation support for it. + +
+ diff --git a/spring-integration-reference/src/resources.xml b/spring-integration-reference/src/resources.xml new file mode 100644 index 0000000000..bd9d8d2281 --- /dev/null +++ b/spring-integration-reference/src/resources.xml @@ -0,0 +1,17 @@ + + + + Additional Resources + +
+ Spring Integration Home + + The definitive source of information about Spring Integration is the + Spring Integration Home at + http://www.springsource.org. That site serves as a hub of + information and is the best place to find up-to-date announcements about the project as well as links to + articles, blogs, and new sample applications. + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/rmi.xml b/spring-integration-reference/src/rmi.xml new file mode 100644 index 0000000000..bc823da3b7 --- /dev/null +++ b/spring-integration-reference/src/rmi.xml @@ -0,0 +1,66 @@ + + + + RMI Support + +
+ Introduction + + This Chapter explains how to use RMI specific channel adapters to distribute a system over multiple JVMs. The first section will deal with sending messages over RMI. The second section shows how to receive messages over RMI. The last section shows how to define rmi channel adapters through the namespace support. + +
+ +
+ Outbound RMI + + To send messages from a channel over RMI, simply define an RmiOutboundGateway. This gateway will use Spring's RmiProxyFactoryBean internally to create a proxy for a remote gateway. Note that to invoke a remote interface that doesn't use Spring Integration you should use a service activator in combination with Spring's RmiProxyFactoryBean. + + + To configure the outbound gateway write a bean definition like this: + + + + ]]> + + +
+ +
+ Inbound RMI + + To receive messages over RMI you need to use a RmiInboundGateway. This gateway can be configured like this + + + ]]> + + +
+ +
+ RMI namespace support + + To configure the inbound gateway you can choose to use the namespace support for it. The following code snippet shows the different configuration options that are supported. + + + + + + + + + ]]> + + + To configure the outbound gateway you can use the namespace support as well. The following code snippet shows the different configuration for an outbound rmi gateway. + ]]> + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/router.xml b/spring-integration-reference/src/router.xml new file mode 100644 index 0000000000..c7965c977b --- /dev/null +++ b/spring-integration-reference/src/router.xml @@ -0,0 +1,205 @@ + + + + Router + +
+ Router Implementations + + Since content-based routing often requires some domain-specific logic, most use-cases will require + Spring Integration's options for delegating to POJOs using the XML namespace support and/or Annotations. + Both of these are discussed below, but first we present a couple implementations that are available + out-of-the-box since they fulfill generic, but common, requirements. + +
+ PayloadTypeRouter + + A PayloadTypeRouter will send Messages to the channel as defined by payload-type + mappings. + + + + + + + +]]> + + + Configuration of PayloadTypeRouter is also supported via the namespace provided by Spring Integration (see ), + which essentially simplifies configuration by combining <router/> configuration and its corresponding implementation defined using <bean/> element + into a single and more concise configuration element. + The example below demonstrates PayloadTypeRouter configuration which is equivalent to the one above using Spring Integration's namespace support: + + + + + +]]> + +
+
+ HeaderValueRouter + + A HeaderValueRouter will send Messages to the channel based on the individual header value mappings. + When HeaderValueRouter is created it is initialized with the name of the header to be evaluated, using constructor-arg. + The value of the header could be one of two things: + + 1. Arbitrary value + + + 2. Channel name + + + If arbitrary value, then a channelResolver should be provided to map header values to channel names. + The example below uses MapBasedChannelResolver to set up a map of header values to channel names. + + + + + + + + + + + + + +]]> + If channelResolver is not specified, then the header value will be treated as a channel name + making configuration much simpler, where no channelResolver needs to be specified. + + + +]]> + + + Similar to the PayloadTypeRouter, configuration of HeaderValueRouter is also supported via namespace support provided by Spring Integration (see ). + The example below demonstrates two types of namespace-based configuration of HeaderValueRouter which are equivalent to the ones above using Spring Integration namespace support: + + 1. Configuration where mapping of header values to channels is required + + + + +]]> + + 2. Configuration where mapping of header values is not required if header values themselves represent the channel names + + ]]> + + + The two router implementations shown above share some common properties, such as "defaultOutputChannel" and "resolutionRequired". + If "resolutionRequired" is set to "true", and the router is unable to determine a target channel (e.g. there is + no matching payload for a PayloadTypeRouter and no "defaultOutputChannel" has been specified), then an Exception + will be thrown. + +
+
+ RecipientListRouter + + A RecipientListRouter will send each received Message to a statically-defined + list of Message Channels: + + + + + + + + +]]> + +
+ + Configuration for RecipientListRouter is also supported via namespace support provided by Spring Integration (see ). + The example below demonstrates namespace-based configuration of RecipientListRouter and all the supported attributes using Spring Integration namespace support: + + + + + +]]> + + + The 'apply-sequence' flag here has the same affect as it does for a publish-subscribe-channel, + and like publish-subscribe-channel it is disabled by default on the recipient-list-router. Refer to + for more information. + +
+ +
+ The <router> element + + The "router" element provides a simple way to connect a router to an input channel, and also accepts the + optional default output channel. The "ref" may provide the bean name of a custom Router implementation + (extending AbstractMessageRouter): + + + + + + +]]> + + Alternatively, the "ref" may point to a simple Object that contains the @Router annotation (see below), or the + "ref" may be combined with an explicit "method" name. When specifying a "method", the same behavior applies as + described in the @Router annotation section below. + ]]> + Using a "ref" attribute is generally recommended if the custom router implementation can be reused in other + <router> definitions. However if the custom router implementation should be scoped to a + concrete definition of the <router>, you can provide an inner bean definition: + + +]]> + + + + Using both the "ref" attribute and an inner handler definition in the same <router> configuration + is not allowed, as it creates an ambiguous condition and will result in an Exception being thrown. + + +
+ +
+ The @Router Annotation + + When using the @Router annotation, the annotated method can return either the + MessageChannel or String type. In the case of the latter, + the endpoint will resolve the channel name as it does for the default output. Additionally, the method can return + either a single value or a collection. When a collection is returned, the reply message will be sent to multiple + channels. To summarize, the following method signatures are all valid. + @Router +public MessageChannel route(Message message) {...} + +@Router +public List<MessageChannel> route(Message message) {...} + +@Router +public String route(Foo payload) {...} + +@Router +public List<String> route(Foo payload) {...} + + + In addition to payload-based routing, a common requirement is to route based on metadata available within the + message header as either a property or attribute. Rather than requiring use of the + Message type as the method parameter, the @Router + annotation may also use the @Header parameter annotation that is documented in . + @Router +public List<String> route(@Header("orderStatus") OrderStatus status) + +
+ + For routing of XML-based Messages, including XPath support, see . + + + \ No newline at end of file diff --git a/spring-integration-reference/src/samples.xml b/spring-integration-reference/src/samples.xml new file mode 100644 index 0000000000..53c19c811c --- /dev/null +++ b/spring-integration-reference/src/samples.xml @@ -0,0 +1,447 @@ + + + + + Spring Integration Samples + + + Starting with the current release of Spring Integration the samples are distributed as independent + Maven-based projects (http://maven.apache.org/) to minimize the setup time. + Since each project is also an Eclipse-based project, they can be imported as is using the Eclipse Import wizard. + If you prefer another IDE, configuration should be very trivial, since a special Maven profile was setup to download all + of the required dependencies for all samples. Detailed instructions on how to build and run the samples are provided in + the README.txt file located in the samples directory of the main distribution. + + +
+ The Cafe Sample + + In this section, we will review a sample application that is included in the Spring Integration + distribution. This sample is inspired by one of the samples featured in Gregor Hohpe's + Ramblings. + + + The domain is that of a Cafe, and the basic flow is depicted in the following diagram: + + + + + + + + + + The Order object may contain multiple OrderItems. Once the order + is placed, a Splitter will break the composite order message into a single message per + drink. Each of these is then processed by a Router that determines whether the drink is hot + or cold (checking the OrderItem object's 'isIced' property). The + Barista prepares each drink, but hot and cold drink preparation are handled by two + distinct methods: 'prepareHotDrink' and 'prepareColdDrink'. The prepared drinks are then sent to the Waiter where + they are aggregated into a Delivery object. + + + Here is the XML configuration: + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +]]> + As you can see, each Message Endpoint is connected to input and/or output channels. Each endpoint will manage + its own Lifecycle (by default endpoints start automatically upon initialization - to prevent that add the + "auto-startup" attribute with a value of "false"). Most importantly, notice that the objects are simple POJOs + with strongly typed method arguments. For example, here is the Splitter: + split(Order order) { + return order.getItems(); + } +}]]> + In the case of the Router, the return value does not have to be a MessageChannel + instance (although it can be). As you see in this example, a String-value representing the channel name is + returned instead. + + + + Now turning back to the XML, you see that there are two <service-activator> elements. Each of these + is delegating to the same Barista instance but different methods: 'prepareHotDrink' + or 'prepareColdDrink' corresponding to the two channels where order items have been routed. + + + + As you can see from the code excerpt above, the barista methods have different delays (the hot drinks take 5 + times as long to prepare). This simulates work being completed at different rates. When the + CafeDemo 'main' method runs, it will loop 100 times sending a single hot drink and a + single cold drink each time. It actually sends the messages by invoking the 'placeOrder' method on the Cafe + interface. Above, you will see that the <gateway> element is specified in the configuration file. This + triggers the creation of a proxy that implements the given 'service-interface' and connects it to a channel. + The channel name is provided on the @Gateway annotation of the Cafe interface. + public interface Cafe { + + @Gateway(requestChannel="orders") + void placeOrder(Order order); + +} + Finally, have a look at the main() method of the CafeDemo itself. + 0) { + context = new FileSystemXmlApplicationContext(args); + } + else { + context = new ClassPathXmlApplicationContext("cafeDemo.xml", CafeDemo.class); + } + Cafe cafe = (Cafe) context.getBean("cafe"); + for (int i = 1; i <= 100; i++) { + Order order = new Order(i); + order.addItem(DrinkType.LATTE, 2, false); + order.addItem(DrinkType.MOCHA, 3, true); + cafe.placeOrder(order); + } +}]]> + + + To run this sample as well as 8 others, refer to the README.txt within the "samples" directory + of the main distribution as described at the beginning of this chapter. + + + When you run cafeDemo, you will see that the cold drinks are initially prepared more quickly than the hot drinks. + Because there is an aggregator, the cold drinks are effectively limited by the rate of the hot drink preparation. + This is to be expected based on their respective delays of 1000 and 5000 milliseconds. However, by configuring a + poller with a concurrent task executor, you can dramatically change the results. For example, you could use a + thread pool executor with 5 workers for the hot drink barista while keeping the cold drink barista as it is: + + + + ]]> + + ]]> + +]]>]]> + + + Also, notice that the worker thread name is displayed with each invocation. You will see that the hot drinks are + prepared by the task-executor threads. If you provide a much shorter poller interval (such as 100 milliseconds), + then you will notice that occasionally it throttles the input by forcing the task-scheduler (the caller) to invoke + the operation. + + + In addition to experimenting with the poller's concurrency settings, you can also add the 'transactional' + sub-element and then refer to any PlatformTransactionManager instance within the context. + +
+ +
+ The XML Messaging Sample + + The xml messaging sample in the org.springframework.integration.samples.xml illustrates how to use + some of the provided components which deal with xml payloads. The sample uses the idea of processing an order for books + represented as xml. + + + First the order is split into a number of messages, each one representing a single order item using + the XPath splitter component. + + + +]]> + + + A service activator is then used to pass the message into a stock checker POJO. The order item document is enriched with information + from the stock checker about order item stock level. This enriched order item message is then used to route the message. In the + case where the order item is in stock the message is routed to the warehouse. The XPath router makes use of a + MapBasedChannelResolver which maps the XPath evaluation result to a channel reference. + + + + + + + + + + + + +]]> + + + Where the order item is not in stock the message is transformed using + xslt into a format suitable for sending to the supplier. + +]]> + +
+ +
+ The OSGi Samples + + This release of Spring Integration includes several samples that are OSGi enabled as well as samples that were + specifically designed to show some of the other benefits of OSGi and Spring Integration when used together. + First lets look at the two familiar examples that are also configured to be valid OSGi bundles. These are + Hello World and Cafe. All you need to do to see these samples work in + an OSGi environment is deploy the generated JAR into such an environment. + + + Use Maven to generate the JAR by executing the 'mvn install' command on either of these projects. This will + generate the JAR file in the target directory. Now you can simply drop that JAR file into the deployment + directory of your OSGi platform. For example, if you are using + SpringSource dm Server, + drop the files into the 'pickup' directory within the dm Server home directory. + + + Prior to deploying and testing Spring Integration samples in the dm Server or any other OSGi server platform, + you must have the Spring Integration and Spring bundles installed on that platform. For example, to install + Spring Integration into SpringSource dm Server, copy all JAR files that are located in the 'dist' directory of + your Spring Integration distribution into the 'repository/bundles/usr' directory of your dm Server instance + (see the + dm Server User Guide + for more detail on how to install bundles). + + + The Spring Integration samples require a few other bundles to be installed. For the 1.0.3 release, the full + list including transitive dependencies is: + + org.apache.commons.codec-1.3.0.jar + org.apache.commons.collections-3.2.0.jar + org.apache.commons.httpclient-3.1.0.jar + org.apache.ws.commons.schema-1.3.2.jar + org.springframework.oxm-1.5.5.A.jar + org.springframework.security-2.0.4.A.jar + org.springframework.ws-1.5.5.A.jar + org.springframework.xml-1.5.5.A.jar + + These are all located within the 'lib' directory of the Spring Integration distribution. So, you can simply + copy those JARs into the dm Server 'repository/bundles/usr' directory as well. + + The Spring Framework bundles (aop, beans, context, etc.) are also included in the 'lib' directory of the + Spring Integration distribution, but they do not need to be installed since they are already part of the + dm Server infrastructure. Also, note that the versions listed above are those included with the Spring + Integration 1.0.3 release. Newer versions of individual JARs may be used as long as they are within the + range specified in the MANIFEST.MF files of those bundles that depend upon them. + + + The bundles listed above are appropriate for a SpringSource dm Server 1.0.x deployment environment + with a Spring Framework 2.5.x foundation. That is the version against which Spring Integration 1.0.3 + has been developed and tested. However, as of the time of the Spring Integration 1.0.3 release, the + Spring Framework 3.0 release candidates are about to be available, and the dm Server 2.0.x milestones + are available. If you want to try running these samples in that environment, then you will need to + replace the Spring Security and Spring Web Services bundles with versions that support Spring 3.0. + The OXM functionality is moving into the Spring Framework itself for the 3.0 release. Otherwise, + Spring Integration 1.0.3 has been superficially tested against the Spring 3.0 snapshots available + at the time of its release. In fact, some internal changes were made in the 1.0.3 release + specifically to support Spring 3.0 (whereas 1.0.2 does not). Spring Integration 2.0 will be built + upon a Spring 3.0 foundation. + + + + To demonstrate some of the benefits of running Spring Integration projects in an OSGi environment (e.g. + modularity, OSGi service dynamics, etc.), we have included a couple new samples that are dedicated to + highlighting those benefits. In the 'samples' directory, you will find the following two projects: + + osgi-inbound (producer bundle) + osgi-outbound (consumer bundle) + + Unlike the other samples in the distribution, these are not Maven enabled. Instead, we have simply configured + them as valid dm Server Bundle projects. That means you can import these projects directly into an STS + workspace using the "Existing Projects into Workspace" option from the Eclipse Import wizard. Then, you can + take advantage of the STS dm Server tools to deploy them into a SpringSource dm Server instance. + + A simple Ant 'build.xml' file has been included within each of these projects as well. The build + files contain a single 'jar' target. Therefore, after these projects have been built within + Eclipse/STS, you can generate the bundle (JAR) directly and deploy it manually. + + + + The structure of these projects is very simple, yet the concepts they showcase are quite powerful. The + 'osgi-inbound' module enables sending a Message to a Publish-Subscribe Channel using a Spring Integration + Gateway proxy. The interesting part, however, is that the Publish-Subscribe Channel is exported as an OSGi + service via the <osgi:service/> element. As a result, any other bundles can be developed, deployed, and + maintained independently yet still subscribe to that channel. + + + The 'osgi-outbound' module is an example of such a subscribing consumer bundle. It uses the corresponding + <osgi:reference/> element to locate the channel exported by the 'osgi-inbound' bundle. It also contains + configuration for a <file:outbound-gateway/> which is a subscriber to that channel and will write the + Message content to a file once it arrives. It then sends a response Message with the name of the file and its + location. + + + To make it easy to run, we've exposed a command-line interface where you can type in the command, the message, + and the file name to execute the demo. This is exposed through the OSGi console. Likewise, the response that + provides the name and location of the resulting file will also be visible within the OSGi console. + + + To run these samples, make sure your OSGi environment is properly configured to host Spring Integration bundles + (as described in the note above). Deploy the producer bundle (osgi-inbound) first, and then deploy the consumer + bundle (osgi-outbound). After you have deployed these bundles, open the OSGi console and type the following + command: + help ]]> + You will see the following amidst the output: + - send text to be written to a file]]> + As you can see, that describes the command that you will be able to use to send messages. If you are interested + in how it is implemented or want to customize message sending logic or even create a new command look at + InboundDemoBundleActivator.java in the consumer bundle. + + When using the SpringSource Tool Suite, you can open the OSGi console by first opening the dm Server + view and then choosing the 'Server Console' tab at the bottom (to open the dm Server view, navigate to + the dm Server instance listed in the 'Servers' view and either double-click or hit F3). Alternatively, + you can open the OSGi console by connecting to port 2401 via telnet (as long as that is enabled, and + for dm Server, it is enabled by default): + telnet localhost 2401 + + + + Now send a message by typing: siSend "Hello World" hello.txt]]> + You will see something similar to the following in the OSGi console: + + + It is not necessary to wrap the message in quotes if it does not contain spaces. + Go ahead and open up the file and verify that the message content was written to it. + + + + Let's assume you wanted to change the directory to which the files are written or make any other change to the + consumer bundle (osgi-outboud). You only need to update the consumer bundle and not the producer bundle. So, go + ahead and change the directory in the 'osgi-outbound.xml' file located within 'src/META-INF/spring' and refresh + the consumer bundle. + + If using STS to deploy to dm Server, the refresh will happen automatically. If replacing bundles manually, + you can issue the command 'refresh n' in the OSGi console (where n would be the ID of the bundle as + displayed at any point after issuing the 'ss' command to see the short status output). + + You will see that the change takes affect immediately. Not only that, you could even start developing and + deploying new bundles that subscribe to the messages produced by the producer bundle the same way as the existing + consumer bundle (osgi-outbound) does. With a publish-subscribe-channel any newly deployed bundles would start + receiving each Message as well. + + If you also want to modify and refresh the producer bundle, be sure to refresh the consumer bundle + afterwards as well. This is necessary because the consumer's subscription must be explicitly re-enabled + after the producer's channel disappears. You could alternatively deploy a relatively static bundle that + defines channels so that producers and consumers can be completely dynamic without affecting each other + at all. In Spring Integration 2.0, we plan to support automatic re-subscription and more through the use + of a Control Bus. + + + + That pretty much wraps up this very simple example. Hopefully it has successfully demonstrated the benefits of + modularity and OSGi service dynamics while working with Spring Integration. Feel free to experiment by following + some of the suggestions mentioned above. For deeper coverage of the applicability of OSGi when used with Spring + Integration, read this blog + by Spring Integration team member Iwein Fuld. + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/security.xml b/spring-integration-reference/src/security.xml new file mode 100644 index 0000000000..9b3ff17399 --- /dev/null +++ b/spring-integration-reference/src/security.xml @@ -0,0 +1,64 @@ + + + + Security in Spring Integration + +
+ Introduction + + Spring Integration provides integration with the + Spring Security project + to allow role based security checks to be applied to channel send and receive invocations. + +
+ +
+ Securing channels + + Spring Integration provides the interceptor ChannelSecurityInterceptor, which extends + AbstractSecurityInterceptor and intercepts send and receive calls on the channel. Access decisions + are then made with reference to ChannelInvocationDefinitionSource which provides the definition of + the send and receive security constraints. The interceptor requires that a valid SecurityContext + has been established by authenticating with Spring Security, see the Spring Security reference documentation for details. + + + Namespace support is provided to allow easy configuration of security constraints. This consists of the secured channels tag which allows + definition of one or more channel name patterns in conjunction with a definition of the security configuration for send and receive. The pattern + is a java.util.regexp.Pattern. + + + + + + +]]> + + + By default the secured-channels namespace element expects a bean named authenticationManager which implements + AuthenticationManager and a bean named accessDecisionManager which implements + AccessDecisionManager. Where this is not the case references to the appropriate beans can be configured + as attributes of the secured-channels element as below. + + + +]]> + + + +
+ + + \ No newline at end of file diff --git a/spring-integration-reference/src/service-activator.xml b/spring-integration-reference/src/service-activator.xml new file mode 100644 index 0000000000..897c44bde3 --- /dev/null +++ b/spring-integration-reference/src/service-activator.xml @@ -0,0 +1,72 @@ + + + + Service Activator + +
+ Introduction + + The Service Activator is the endpoint type for connecting any Spring-managed Object to an input channel so that + it may play the role of a service. If the service produces output, it may also be connected to an output channel. + Alternatively, an output producing service may be located at the end of a processing pipeline or message flow in + which case, the inbound Message's "replyChannel" header can be used. This is the default behavior if no output + channel is defined, and as with most of the configuration options you'll see here, the same behavior actually + applies for most of the other components we have seen. + +
+ +
+ The <service-activator/> Element + + To create a Service Activator, use the 'service-activator' element with the 'input-channel' and 'ref' attributes: + <service-activator input-channel="exampleChannel" ref="exampleHandler"/> + + + The configuration above assumes that "exampleHandler" either contains a single method annotated with the + @ServiceActivator annotation or that it contains only one public method at all. To delegate to an explicitly + defined method of any object, simply add the "method" attribute. + <service-activator input-channel="exampleChannel" ref="somePojo" method="someMethod"/> + + + In either case, when the service method returns a non-null value, the endpoint will attempt to send the reply + message to an appropriate reply channel. To determine the reply channel, it will first check if an + "output-channel" was provided in the endpoint configuration: + <service-activator input-channel="exampleChannel" output-channel="replyChannel" + ref="somePojo" method="someMethod"/> + If no "output-channel" is available, it will then check the Message's REPLY_CHANNEL header + value. If that value is available, it will then check its type. If it is a + MessageChannel, the reply message will be sent to that channel. If it is a + String, then the endpoint will attempt to resolve the channel name to a channel instance. + If the channel cannot be resolved, then a ChannelResolutionException will be thrown. + + + The argument in the service method could be either a Message or an arbitrary type. If the latter, then it will + be assumed that it is a Message payload, which will be extracted from the message and injected into such service + method. This is generally the recommended approach as it follows and promotes a POJO model when working with Spring + Integration. Arguments may also have @Header, @Headers or @MessageMapping annotations as described in + + + Since v1.0.3 of Spring Integration, the service method is not required to have an argument at all, which means you + can now implement event-style Service Activators, where all you care about is an invocation of the service method, + not worrying about the contents of the message. Think of it as a NULL JMS message. An example use-case for such an + implementation could be a simple counter/monitor of messages deposited on the input channel. + + + Using a "ref" attribute is generally recommended if the custom Service Activator handler implementation can be reused + in other <service-activator> definitions. However if the custom Service Activator handler implementation + should be scoped to a single definition of the <service-activator>, you can use an inner bean definition: + + +]]> + + + + Using both the "ref" attribute and an inner handler definition in the same <service-activator> + configuration is not allowed, as it creates an ambiguous condition and will result in an Exception being thrown. + + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/splitter.xml b/spring-integration-reference/src/splitter.xml new file mode 100644 index 0000000000..439eff2b5b --- /dev/null +++ b/spring-integration-reference/src/splitter.xml @@ -0,0 +1,158 @@ + + + + Splitter + +
+ Introduction + + The Splitter is a component whose role is to partition a message in + several parts, and send the resulting messages to be processed + independently. Very often, they are upstream producers in a pipeline that + includes an Aggregator. +
+ +
+ Programming model + + The API for performing splitting consists from one base class, + AbstractMessageSplitter, which is a MessageHandler implementation, + encapsulating features which are common to splitters, such as filling in + the appropriate message headers CORRELATION_ID, SEQUENCE_SIZE, and + SEQUENCE_NUMBER on the messages that are produced. This allows to track + down the messages and the results of their processing (in a typical + scenario, these headers would be copied over to the messages that are + produced by the various transforming endpoints), and use them, for + example, in a Composed Message Processor scenario. + + An excerpt from AbstractMessageSplitter can be seen below: + + public abstract class AbstractMessageSplitter + extends AbstractReplyProducingMessageConsumer { + ... + protected abstract Object splitMessage(Message<?> message); + +} + + For implementing a specific Splitter in an application, a developer + can extend AbstractMessageSplitter and implement the splitMessage method, + thus defining the actual logic for splitting the messages. The return + value can be one of the following: + + + + a Collection (or subclass thereof) or an array of Message + objects - in this case the messages will be sent as such (after the + CORRELATION_ID, SEQUENCE_SIZE and SEQUENCE_NUMBER are populated). + Using this approach gives more control to the developer, for example + for populating custom message headers as part of the splitting + process. + + + + a Collection (or subclass thereof) or an array of non-Message + objects - works like the prior case, except that each collection + element will be used as a Message payload. Using this approach allows + developers to focus on the domain objects without having to consider + the Messaging system and produces code that is easier to test. + + + + a Message or non-Message object (but not a Collection or an + Array) - it works like the previous cases, except that there is a + single message to be sent out. + + + + In Spring Integration, any POJO can implement the splitting + algorithm, provided that it defines a method that accepts a single + argument and has a return value. In this case, the return value of the + method will be interpreted as described above. The input argument might + either be a Message or a simple POJO. In the latter case, the splitter + will receive the payload of the incoming message. Since this decouples + the code from the Spring Integration API and will typically be easier + to test, it is the recommended approach. +
+ +
+ Configuring a Splitter using XML + + A splitter can be configured through XML as follows:<channel id="inputChannel"/> + +<splitter id="splitter" + ref="splitterBean" + method="split" + input-channel="inputChannel" + output-channel="outputChannel" /> + +<channel id="outputChannel"/> + +<beans:bean id="splitterBean" class="sample.PojoSplitter"/> + + The id of the splitter is + optional. + + + + A reference to a bean defined in the application context. The + bean must implement the splitting logic as described in the section + above. Optional. + If reference to a bean is not provided, then it is assumed that the payload of the Message that arrived on the input-channel is + an implementation of java.util.Collection and the default splitting logic will be applied on such Collection, + incorporating each individual element into a Message and depositing it on the output-channel. + + + + + The method (defined on the bean specified above) that + implements the splitting logic. + Optional. + + + + The input channel of the splitter. + Required. + + + + The channel where the splitter will send the results of + splitting the incoming message. Optional (because incoming + messages can specify a reply channel themselves). + + + + Using a "ref" attribute is generally recommended if the custom splitter handler implementation can be reused in other + <splitter> definitions. However if the custom splitter handler implementation should be scoped to a + single definition of the <splitter>, you can configure an inner bean definition: + + +]]> + + + + Using both a "ref" attribute and an inner handler definition in the same <splitter> + configuration is not allowed, as it creates an ambiguous condition and will result in an Exception being thrown. + + +
+ +
+ Configuring a Splitter with Annotations + + The @Splitter annotation is + applicable to methods that expect either the + Message type or the message payload type, + and the return values of the method should be a collection of any type. If + the returned values are not actual Message + objects, then each of them will be sent as the payload of a message. Those + messages will be sent to the output channel as designated for the endpoint + on which the @Splitter is defined. + @Splitter +List<LineItem> extractItems(Order order) { + return order.getItems() +} +
+ + diff --git a/spring-integration-reference/src/spring-integration-reference.xml b/spring-integration-reference/src/spring-integration-reference.xml new file mode 100644 index 0000000000..63183d58a5 --- /dev/null +++ b/spring-integration-reference/src/spring-integration-reference.xml @@ -0,0 +1,85 @@ + + + + + Spring Integration Reference Manual + Spring Integration 2.0.0 M4 + Spring Integration + 2.0.0 Milestone 4 + + + + + + + + + + + + + Mark + Fisher + + + Marius + Bogoevici + + + Iwein + Fuld + + + Jonas + Partner + + + Oleg + Zhurakousky + + + Gary + Russell + + + + © SpringSource Inc., 2010 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + diff --git a/spring-integration-reference/src/stream.xml b/spring-integration-reference/src/stream.xml new file mode 100644 index 0000000000..7336b843fa --- /dev/null +++ b/spring-integration-reference/src/stream.xml @@ -0,0 +1,91 @@ + + + + Stream Support + +
+ Introduction + + In many cases application data is obtained from a stream. It is not recommended to send a reference to a Stream as a message payload to a consumer. Instead messages are created from data that is read from an input stream and message payloads are written to an output stream one by one. + +
+ +
+ Reading from streams + + Spring Integration provides two adapters for streams. Both ByteStreamReadingMessageSource and + CharacterStreamReadingMessageSource implement MessageSource. + By configuring one of these within a channel-adapter element, the polling period can be configured, + and the Message Bus can automatically detect and schedule them. The byte stream version requires an + InputStream, and the character stream version requires a Reader as + the single constructor argument. The ByteStreamReadingMessageSource also accepts the 'bytesPerMessage' + property to determine how many bytes it will attempt to read into each Message. The + default value is 1024 + + + + + + + +]]> + + +
+ +
+ Writing to streams + + For target streams, there are also two implementations: ByteStreamWritingMessageHandler and + CharacterStreamWritingMessageHandler. Each requires a single constructor argument - + OutputStream for byte streams or Writer for character streams, + and each provides a second constructor that adds the optional 'bufferSize'. Since both of these + ultimately implement the MessageHandler interface, they can be referenced from a + channel-adapter configuration as described in more detail in + . + + + + + + + +]]> + + +
+ + + +
+ Stream namespace support + + To reduce the configuration needed for stream related channel adapters there is a namespace defined. The following schema locations are needed to use it. + +]]> + + + To configure the inbound channel adapter the following code snippet shows the different configuration options that are supported. + + +]]> + + + To configure the outbound channel adapter you can use the namespace support as well. The following code snippet shows the different configuration for an outbound channel adapters. + + + + + + + + ]]> + +
+ \ No newline at end of file diff --git a/spring-integration-reference/src/transformer.xml b/spring-integration-reference/src/transformer.xml new file mode 100644 index 0000000000..32f41058af --- /dev/null +++ b/spring-integration-reference/src/transformer.xml @@ -0,0 +1,122 @@ + + + + Transformer + +
+ Introduction + + Message Transformers play a very important role in enabling the loose-coupling of Message Producers and Message + Consumers. Rather than requiring every Message-producing component to know what type is expected by the next + consumer, Transformers can be added between those components. Generic transformers, such as one that converts a + String to an XML Document, are also highly reusable. + + + For some systems, it may be best to provide a + Canonical Data Model, but Spring + Integration's general philosophy is not to require any particular format. Rather, for maximum flexibility, Spring + Integration aims to provide the simplest possible model for extension. As with the other endpoint types, the use + of declarative configuration in XML and/or Annotations enables simple POJOs to be adapted for the role of Message + Transformers. These configuration options will be described below. + + For the same reason of maximizing flexibility, Spring does not require XML-based Message payloads. + Nevertheless, the framework does provide some convenient Transformers for dealing with XML-based payloads if + that is indeed the right choice for your application. For more information on those transformers, see + . + + +
+ +
+ The <transformer> Element + + The <transformer> element is used to create a Message-transforming endpoint. In addition to "input-channel" + and "output-channel" attributes, it requires a "ref". The "ref" may either point to an Object that contains the + @Transformer annotation on a single method (see below) or it may be combined with an explicit method name value + provided via the "method" attribute. + +]]> + + + Using a "ref" attribute is generally recommended if the custom transformer handler implementation can be reused in + other <transformer> definitions. However if the custom transformer handler implementation should + be scoped to a single definition of the <transformer>, you can define an inner bean definition: + + +]]> + + + + Using both the "ref" attribute and an inner handler definition in the same <transformer> + configuration is not allowed, as it creates an ambiguous condition and will result in an Exception being thrown. + + + + The method that is used for transformation may expect either the Message type or + the payload type of inbound Messages. It may also accept Message header values either individually or as a full + map by using the @Header and @Headers parameter annotations respectively. The return value of the method can be + any type. If the return value is itself a Message, that will be passed along to + the transformer's output channel. If the return type is a Map, and the original Message payload was + not a Map, the entries in that Map will be added to the Message headers of the original + Message (the keys must be Strings). If the return value is null, then no reply Message will + be sent (effectively the same behavior as a Message Filter returning false). Otherwise, the return value will be + sent as the payload of an outbound reply Message. + + + There are a also a few Transformer implementations available out of the box. Because, it is fairly common + to use the toString() representation of an Object, Spring Integration provides an + ObjectToStringTransformer whose output is a Message with a String payload. That String + is the result of invoking the toString operation on the inbound Message's payload. + ]]> + A potential example for this would be sending some arbitrary object to the 'outbound-channel-adapter' in the + file namespace. Whereas that Channel Adapter only supports String, byte-array, or + java.io.File payloads by default, adding this transformer immediately before the + adapter will handle the necessary conversion. Of course, that works fine as long as the result of the + toString() call is what you want to be written to the File. Otherwise, you can + just provide a custom POJO-based Transformer via the generic 'transformer' element shown previously. + + When debugging, this transformer is not typically necessary since the 'logging-channel-adapter' is capable + of logging the Message payload. Refer to for more detail. + + + + If you need to serialize an Object to a byte array or deserialize a byte array back into an Object, + Spring Integration provides symmetrical serialization transformers. + + + ]]> + + + If you only need to add headers to a Message, and they are not dynamically determined by Message content, + then referencing a custom implementation may be overkill. For that reason, Spring Integration provides the + 'header-enricher' element. +
+
+ ]]> + +
+ +
+ The @Transformer Annotation + + The @Transformer annotation can also be added to methods that expect either the + Message type or the message payload type. The return value will be handled in the + exact same way as described above in the section describing the <transformer> element. + @Transformer +Order generateOrder(String productId) { + return new Order(productId); +} + + + Transformer methods may also accept the @Header and @Headers annotations that is documented in + @Transformer +Order generateOrder(String productId, @Header("customerName") String customer) { + return new Order(productId, customer); +} + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/ws.xml b/spring-integration-reference/src/ws.xml new file mode 100644 index 0000000000..23a5659dd5 --- /dev/null +++ b/spring-integration-reference/src/ws.xml @@ -0,0 +1,134 @@ + + + + Web Services Support + +
+ Outbound Web Service Gateways + + To invoke a Web Service upon sending a message to a channel, there are two options - both of which build + upon the Spring Web Services + project: SimpleWebServiceOutboundGateway and + MarshallingWebServiceOutboundGateway. The former will accept either a + String or javax.xml.transform.Source as the message + payload. The latter provides support for any implementation of the Marshaller + and Unmarshaller interfaces. Both require a Spring Web Services + DestinationProvider for determining the URI of the Web Service to be + called. simpleGateway = new SimpleWebServiceOutboundGateway(destinationProvider); + + marshallingGateway = new MarshallingWebServiceOutboundGateway(destinationProvider, marshaller); + + + When using the namespace support described below, you will only need to set a URI. Internally, the parser + will configure a fixed URI DestinationProvider implementation. If you do need dynamic resolution of the + URI at runtime, however, then the DestinationProvider can provide such behavior as looking up the URI from + a registry. See the Spring Web Services + javadoc for + more information about the DestinationProvider strategy. + + + + For more detail on the inner workings, see the Spring Web Services reference guide's chapter covering + client access + as well as the chapter covering + Object/XML mapping. + +
+ +
+ Inbound Web Service Gateways + + To send a message to a channel upon receiving a Web Service invocation, there are two options again: SimpleWebServiceInboundGateway and + MarshallingWebServiceInboundGateway. The former will extract a javax.xml.transform.Source + from the WebServiceMessage and set it as the message + payload. The latter provides support for implementation of the Marshaller + and Unmarshaller interfaces. + If the incoming web service message is a SOAP message the SOAP Action header will be added to the headers of the + Message that is forwarded onto the request channel. + + simpleGateway = new SimpleWebServiceInboundGateway(); + simpleGateway.setRequestChannel(forwardOntoThisChannel); + simpleGateway.setReplyChannel(listenForResponseHere); //Optional + + marshallingGateway = new MarshallingWebServiceInboundGateway(marshaller); + //set request and optionally reply channel + +Both gateways implement the Spring Web Services MessageEndpoint +interface, so they can be configured with a MessageDispatcherServlet +as per standard Spring Web Services configuration. + + + For more detail on how to use these components, see the Spring Web Services reference guide's chapter covering + creating a Web Service. + The chapter covering + Object/XML mapping is also applicable again. + +
+
+ Web Service Namespace Support + + To configure an outbound Web Service Gateway, use the "outbound-gateway" element from the "ws" namespace: + ]]> + + Notice that this example does not provide a 'reply-channel'. If the Web Service were to + return a non-empty response, the Message containing that response would be sent to the + reply channel provided in the request Message's REPLY_CHANNEL header, and if that were + not available a channel resolution Exception would be thrown. If you want to send the + reply to another channel instead, then provide a 'reply-channel' attribute on the + 'outbound-gateway' element. + + + When invoking a Web Service that returns an empty response after using a String payload + for the request Message, no reply Message will be sent by default. + Therefore you don't need to set a 'reply-channel' or have a REPLY_CHANNEL header in the + request Message. If for any reason you actually do want to receive + the empty response as a Message, then provide the 'ignore-empty-responses' attribute with + a value of false (this only applies for Strings, because using a + Source or Document object simply leads to a NULL response and will therefore + never generate a reply Message). + + + To set up an inbound Web Service Gateway, use the "inbound-gateway": + ]]> + + To use Spring OXM Marshallers and/or Unmarshallers, provide bean references. For outbound: + ]]> + And for inbound: + ]]> + + + Most Marshaller implementations also implement the + Unmarshaller interface. When using such a + Marshaller, only the "marshaller" + attribute is necessary. Even when using a Marshaller, + you may also provide a reference for the "request-callback" on the outbound gateways. + + + + For either outbound gateway type, a "destination-provider" attribute can be specified instead of the "uri" + (exactly one of them is required). You can then reference any Spring Web Services DestinationProvider + implementation (e.g. to lookup the URI at runtime from a registry). + + + For either outbound gateway type, the "message-factory" attribute can also be configured with a reference to any + Spring Web Services WebServiceMessageFactory implementation. + + + For the simple inbound gateway type, the "extract-payload" attribute can be set to false to forward + the entire WebServiceMessage instead of just its payload as a + Message to the request channel. This might be useful, for example, + when a custom Transformer works against the WebServiceMessage directly. + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/src/xml.xml b/spring-integration-reference/src/xml.xml new file mode 100644 index 0000000000..ef2d39f171 --- /dev/null +++ b/spring-integration-reference/src/xml.xml @@ -0,0 +1,391 @@ + + + + Dealing with XML Payloads + +
+ Introduction + + Spring Integration's XML support extends the Spring Integration Core with + implementations of splitter, transformer, selector and router designed + to make working with xml messages in Spring Integration simple. The provided messaging + components are designed to work with xml represented in a range of formats including + instances of + java.lang.String, org.w3c.dom.Document + and javax.xml.transform.Source. It should be noted however that + where a DOM representation is required, for example in order to evaluate an XPath expression, + the String payload will be converted into the required type and then + converted back again to String. Components that require an instance of + DocumentBuilder will create a namespace aware instance if one is + not provided. Where greater control of the document being created is required an appropriately + configured instance of DocumentBuilder should be provided. + +
+
+ Transforming xml payloads + + This section will explain the workings of + UnmarshallingTransformer, + MarshallingTransformer, + XsltPayloadTransformer + and how to configure them as + beans. All of the provided xml transformers extend + AbstractTransformer or AbstractPayloadTransformer + and therefore implement Transformer. When configuring xml + transformers as beans in Spring Integration you would normally configure the transformer + in conjunction with either a MessageTransformingChannelInterceptor or a + MessageTransformingHandler. This allows the transformer to be used as either an interceptor, + which transforms the message as it is sent or received to the channel, or as an endpoint. Finally the + namespace support will be discussed which allows for the simple configuration of the transformers as + elements in XML. + + + UnmarshallingTransformer allows an xml Source + to be unmarshalled using implementations of Spring OXM Unmarshaller. + Spring OXM provides several implementations supporting marshalling and unmarshalling using JAXB, + Castor and JiBX amongst others. Since the unmarshaller requires an instance of + Source where the message payload is not currently an instance of + Source, conversion will be attempted. Currently String + and org.w3c.dom.Document payloads are supported. Custom conversion to a + Source is also supported by injecting an implementation of + SourceFactory. + + + + + + +]]> + + + The MarshallingTransformer allows an object graph to be converted + into xml using a Spring OXM Marshaller. By default the + MarshallingTransformer will return a DomResult. + However the type of result can be controlled by configuring an alternative ResultFactory + such as StringResultFactory. In many cases it will be more convenient to transform + the payload into an alternative xml format. To achieve this configure a + ResultTransformer. Two implementations are provided, one which converts to + String and another which converts to Document. + + + + + + + + + +]]> + + + By default, the MarshallingTransformer will pass the payload Object + to the Marshaller, but if its boolean "extractPayload" property + is set to "false", the entire Message instance will be passed + to the Marshaller instead. That may be useful for certain custom + implementations of the Marshaller interface, but typically the + payload is the appropriate source Object for marshalling when delegating to any of the various + out-of-the-box Marshaller implementations. + + + XsltPayloadTransformer transforms xml payloads using xsl. + The transformer requires an instance of either Resource or + Templates. Passing in a Templates instance + allows for greater configuration of the TransformerFactory used to create + the template instance. As in the case of XmlPayloadMarshallingTransformer + by default XsltPayloadTransformer will create a message with a + Result payload. This can be customised by providing a + ResultFactory and/or a ResultTransformer. + + + + + +]]> + +
+
+ + Namespace support for xml transformers + + Namespace support for all xml transformers is provided in the Spring Integration xml namespace, + a template for which can be seen below. The namespace support for transformers creates an instance of either + EventDrivenConsumer or PollingConsumer + according to the type of the provided input channel. The namespace support is designed + to reduce the amount of xml configuration by allowing the creation of an endpoint and transformer + using one element. + + +]]> + The namespace support for UnmarshallingTransformer is shown below. + Since the namespace is now creating an endpoint instance rather than a transformer, + a poller can also be nested within the element to control the polling of the input channel. + + + + + + + + ]]> + + + + The namespace support for the marshalling transformer requires an input channel, output channel and a + reference to a marshaller. The optional result-type attribute can be used to control the type of result created, + valid values are StringResult or DomResult (the default). Where the provided result types are not sufficient a + reference to a custom implementation of ResultFactory can be provided as an alternative + to setting the result-type attribute using the result-factory attribute. An optional result-transformer can also be + specified in order to convert the created Result after marshalling. + + + + +]]> + + + + Namespace support for the XsltPayloadTransformer allows either a resource to be passed in in order to create the + Templates instance or alternatively a precreated Templates + instance can be passed in as a reference. In common with the marshalling transformer the type of the result output can + be controlled by specifying either the result-factory or result-type attribute. A result-transfomer attribute can also + be used to reference an implementation of ResultTransfomer where conversion of the result + is required before sending. + +]]> + +
+ +
+ Splitting xml messages + + XPathMessageSplitter supports messages with either + String or Document payloads. + The splitter uses the provided XPath expression to split the payload into a number of + nodes. By default this will result in each Node instance + becoming the payload of a new message. Where it is preferred that each message be a Document + the createDocuments flag can be set. Where a String payload is passed + in the payload will be converted then split before being converted back to a number of String + messages. The XPath splitter implements MessageHandler and should + therefore be configured in conjunction with an appropriate endpoint (see the namespace support below + for a simpler configuration alternative). + + + + + + + + + +]]> + + +
+ +
+ Routing xml messages using XPath + + Two Router implementations based on XPath are provided XPathSingleChannelRouter and + XPathMultiChannelRouter. The implementations differ in respect to how many channels + any given message may be routed to, exactly one in the case of the single channel version + or zero or more in the case of the multichannel router. Both evaluate an XPath + expression against the xml payload of the message, supported payload types by default + are Node, Document and + String. For other payload types a custom implementation + of XmlPayloadConverter can be provided. The router + implementations use ChannelResolver to convert the + result(s) of the XPath expression to a channel name. By default a + BeanFactoryChannelResolver strategy will be used, this means that the string returned by the XPath + evaluation should correspond directly to the name of a channel. Where this is not the case + an alternative implementation of ChannelResolver can + be used. Where there is a simple mapping from Xpath result to channel name + the provided MapBasedChannelResolver can be used. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +]]> + +
+ +
+ Selecting xml messages using XPath + + Two MessageSelector implementations are provided, + BooleanTestXPathMessageSelector and StringValueTestXPathMessageSelector. + BooleanTestXPathMessageSelector requires an XPathExpression which evaluates to a boolean, + for example boolean(/one/two) which will only select messages which have an element named + two which is a child of a root element named one. StringValueTestXPathMessageSelector + evaluates any XPath expression as a String and compares the result with the provided value. + + + + + + + + + + + + + + + + + + + + +]]> +
+ + +
+ XPath components namespace support + All XPath based components have namespace support allowing them to be configured as + Message Endpoints with the exception of the XPath selectors which are not designed to act as + endpoints. Each component allows the XPath to either be referenced at the top level or configured via a nested + xpath-expression element. So the following configurations of an xpath-selector are all valid and represent the general + form of XPath namespace support. All forms of XPath expression result in the creation of an + XPathExpression using the Spring XPathExpressionFactory + + + + + + + + + + + + + + + + + + + + + + + + + + +]]> + + + XPath splitter namespace support allows the creation of a Message Endpoint with an input channel and output channel. + + + + + + + + + + + +]]> + + + XPath router namespace support allows for the creation of a Message Endpoint with an input channel but no output channel + since the output channel is determined dynamically. The multi-channel attribute causes the creation of a multi channel router capable of + routing a single message to many channels when true and a single channel router when false. + + + + + + + + + + + +]]> + +
+ + \ No newline at end of file diff --git a/spring-integration-reference/styles/html/custom.xsl b/spring-integration-reference/styles/html/custom.xsl new file mode 100644 index 0000000000..81e6ab2358 --- /dev/null +++ b/spring-integration-reference/styles/html/custom.xsl @@ -0,0 +1,136 @@ + + + + + + + '5' + + + + 1 + 0 + 1 + + + + images/ + .gif + + 120 + images/callouts/ + .gif + + + css/stylesheet.css + text/css + book toc,title + + text-align: left + + + + + + + + + + + 3 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Begin Google Analytics code + + + End Google Analytics code + + + + + Begin LoopFuse code + + + End LoopFuse code + + + \ No newline at end of file diff --git a/spring-integration-reference/styles/html/titlepage.xml b/spring-integration-reference/styles/html/titlepage.xml new file mode 100644 index 0000000000..09539c068c --- /dev/null +++ b/spring-integration-reference/styles/html/titlepage.xml @@ -0,0 +1,61 @@ + + + + + + + + + + + + + <subtitle/> + <!-- <corpauthor/> + <authorgroup/> + <author/> + <mediaobject/> --> + <othercredit/> + <releaseinfo/> + <copyright/> + <legalnotice/> + <pubdate/> + <revision/> + <revhistory/> + <abstract/> + </t:titlepage-content> + + <t:titlepage-content t:side="verso"> + </t:titlepage-content> + + <t:titlepage-separator> + <hr/> + </t:titlepage-separator> + + <t:titlepage-before t:side="recto"> + </t:titlepage-before> + + <t:titlepage-before t:side="verso"> + </t:titlepage-before> +</t:titlepage> + +</t:templates> diff --git a/spring-integration-reference/styles/pdf/custom.xsl b/spring-integration-reference/styles/pdf/custom.xsl new file mode 100644 index 0000000000..2905ee3c21 --- /dev/null +++ b/spring-integration-reference/styles/pdf/custom.xsl @@ -0,0 +1,518 @@ +<?xml version="1.0" encoding="UTF-8"?> + +<!-- + Licensed to the Apache Software Foundation (ASF) under one + or more contributor license agreements. See the NOTICE file + distributed with this work for additional information + regarding copyright ownership. The ASF licenses this file + to you under the Apache License, Version 2.0 (the + "License"); you may not use this file except in compliance + with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, + software distributed under the License is distributed on an + "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + KIND, either express or implied. See the License for the + specific language governing permissions and limitations + under the License. +--> + +<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" + xmlns:fo="http://www.w3.org/1999/XSL/Format" + xmlns:xslthl="http://xslthl.sf.net" + exclude-result-prefixes="xslthl" + version='1.0'> + +<!-- Use nice graphics for admonitions --> + <xsl:param name="admon.graphics">'1'</xsl:param> + <xsl:param name="admon.graphics.path">@file.prefix@@dbf.xsl@/images/</xsl:param> + <xsl:param name="draft.watermark.image" select="'@file.prefix@@dbf.xsl@/images/draft.png'"/> + <xsl:param name="paper.type" select="'@paper.type@'"/> + + <xsl:param name="page.margin.top" select="'1cm'"/> + <xsl:param name="region.before.extent" select="'1cm'"/> + <xsl:param name="body.margin.top" select="'1.5cm'"/> + + <xsl:param name="body.margin.bottom" select="'1.5cm'"/> + <xsl:param name="region.after.extent" select="'1cm'"/> + <xsl:param name="page.margin.bottom" select="'1cm'"/> + <xsl:param name="title.margin.left" select="'0cm'"/> + +<!--################################################### + Header + ################################################### --> + +<!-- More space in the center header for long text --> + <xsl:attribute-set name="header.content.properties"> + <xsl:attribute name="font-family"> + <xsl:value-of select="$body.font.family"/> + </xsl:attribute> + <xsl:attribute name="margin-left">-5em</xsl:attribute> + <xsl:attribute name="margin-right">-5em</xsl:attribute> + </xsl:attribute-set> + +<!--################################################### + Table of Contents + ################################################### --> + + <xsl:param name="generate.toc"> + book toc,title + </xsl:param> + +<!--################################################### + Custom Header + ################################################### --> + + <xsl:template name="header.content"> + <xsl:param name="pageclass" select="''"/> + <xsl:param name="sequence" select="''"/> + <xsl:param name="position" select="''"/> + <xsl:param name="gentext-key" select="''"/> + + <xsl:variable name="Version"> + <xsl:choose> + <xsl:when test="//productname"> + <xsl:value-of select="//productname"/><xsl:text> </xsl:text> + </xsl:when> + <xsl:otherwise> + <xsl:text>please define productname in your docbook file!</xsl:text> + </xsl:otherwise> + </xsl:choose> + </xsl:variable> + + <xsl:choose> + <xsl:when test="$sequence='blank'"> + <xsl:choose> + <xsl:when test="$position='center'"> + <xsl:value-of select="$Version"/> + </xsl:when> + + <xsl:otherwise> + <!-- nop --> + </xsl:otherwise> + </xsl:choose> + </xsl:when> + + <xsl:when test="$pageclass='titlepage'"> + <!-- nop: other titlepage sequences have no header --> + </xsl:when> + + <xsl:when test="$position='center'"> + <xsl:value-of select="$Version"/> + </xsl:when> + + <xsl:otherwise> + <!-- nop --> + </xsl:otherwise> + </xsl:choose> + </xsl:template> + +<!--################################################### + Custom Footer + ################################################### --> + + <xsl:template name="footer.content"> + <xsl:param name="pageclass" select="''"/> + <xsl:param name="sequence" select="''"/> + <xsl:param name="position" select="''"/> + <xsl:param name="gentext-key" select="''"/> + + <xsl:variable name="Version"> + <xsl:choose> + <xsl:when test="//releaseinfo"> + <xsl:value-of select="//releaseinfo"/> + </xsl:when> + <xsl:otherwise> + <!-- nop --> + </xsl:otherwise> + </xsl:choose> + </xsl:variable> + + <xsl:variable name="Title"> + <xsl:value-of select="//title"/> + </xsl:variable> + + <xsl:choose> + <xsl:when test="$sequence='blank'"> + <xsl:choose> + <xsl:when test="$double.sided != 0 and $position = 'left'"> + <xsl:value-of select="$Version"/> + </xsl:when> + + <xsl:when test="$double.sided = 0 and $position = 'center'"> + <!-- nop --> + </xsl:when> + + <xsl:otherwise> + <fo:page-number/> + </xsl:otherwise> + </xsl:choose> + </xsl:when> + + <xsl:when test="$pageclass='titlepage'"> + <!-- nop: other titlepage sequences have no footer --> + </xsl:when> + + <xsl:when test="$double.sided != 0 and $sequence = 'even' and $position='left'"> + <fo:page-number/> + </xsl:when> + + <xsl:when test="$double.sided != 0 and $sequence = 'odd' and $position='right'"> + <fo:page-number/> + </xsl:when> + + <xsl:when test="$double.sided = 0 and $position='right'"> + <fo:page-number/> + </xsl:when> + + <xsl:when test="$double.sided != 0 and $sequence = 'odd' and $position='left'"> + <xsl:value-of select="$Version"/> + </xsl:when> + + <xsl:when test="$double.sided != 0 and $sequence = 'even' and $position='right'"> + <xsl:value-of select="$Version"/> + </xsl:when> + + <xsl:when test="$double.sided = 0 and $position='left'"> + <xsl:value-of select="$Version"/> + </xsl:when> + + <xsl:when test="$position='center'"> + <xsl:value-of select="$Title"/> + </xsl:when> + + <xsl:otherwise> + <!-- nop --> + </xsl:otherwise> + </xsl:choose> + </xsl:template> + + <xsl:template match="processing-instruction('hard-pagebreak')"> + <fo:block break-before='page'/> + </xsl:template> + +<!--################################################### + Extensions + ################################################### --> + +<!-- These extensions are required for table printing and other stuff --> + <xsl:param name="use.extensions">1</xsl:param> + <xsl:param name="tablecolumns.extension">0</xsl:param> + <xsl:param name="callout.extensions">1</xsl:param> + <xsl:param name="fop.extensions">1</xsl:param> + +<!--################################################### + Paper & Page Size + ################################################### --> + +<!-- Paper type, no headers on blank pages, no double sided printing --> + <xsl:param name="double.sided">0</xsl:param> + <xsl:param name="headers.on.blank.pages">0</xsl:param> + <xsl:param name="footers.on.blank.pages">0</xsl:param> + +<!--################################################### + Fonts & Styles + ################################################### --> + + <xsl:param name="hyphenate">false</xsl:param> + +<!-- Default Font size --> + <xsl:param name="body.font.master">11</xsl:param> + <xsl:param name="body.font.small">8</xsl:param> + +<!-- Line height in body text --> + <xsl:param name="line-height">1.4</xsl:param> + +<!-- Chapter title size --> + <xsl:attribute-set name="chapter.titlepage.recto.style"> + <xsl:attribute name="text-align">left</xsl:attribute> + <xsl:attribute name="font-weight">bold</xsl:attribute> + <xsl:attribute name="font-size"> + <xsl:value-of select="$body.font.master * 1.8"/> + <xsl:text>pt</xsl:text> + </xsl:attribute> + </xsl:attribute-set> + +<!-- Why is the font-size for chapters hardcoded in the XSL FO templates? + Let's remove it, so this sucker can use our attribute-set only... --> + <xsl:template match="title" mode="chapter.titlepage.recto.auto.mode"> + <fo:block xmlns:fo="http://www.w3.org/1999/XSL/Format" + xsl:use-attribute-sets="chapter.titlepage.recto.style"> + <xsl:call-template name="component.title"> + <xsl:with-param name="node" select="ancestor-or-self::chapter[1]"/> + </xsl:call-template> + </fo:block> + </xsl:template> + +<!-- Sections 1, 2 and 3 titles have a small bump factor and padding --> + <xsl:attribute-set name="section.title.level1.properties"> + <xsl:attribute name="space-before.optimum">0.8em</xsl:attribute> + <xsl:attribute name="space-before.minimum">0.8em</xsl:attribute> + <xsl:attribute name="space-before.maximum">0.8em</xsl:attribute> + <xsl:attribute name="font-size"> + <xsl:value-of select="$body.font.master * 1.5"/> + <xsl:text>pt</xsl:text> + </xsl:attribute> + <xsl:attribute name="space-after.optimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.minimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.maximum">0.1em</xsl:attribute> + </xsl:attribute-set> + <xsl:attribute-set name="section.title.level2.properties"> + <xsl:attribute name="space-before.optimum">0.6em</xsl:attribute> + <xsl:attribute name="space-before.minimum">0.6em</xsl:attribute> + <xsl:attribute name="space-before.maximum">0.6em</xsl:attribute> + <xsl:attribute name="font-size"> + <xsl:value-of select="$body.font.master * 1.25"/> + <xsl:text>pt</xsl:text> + </xsl:attribute> + <xsl:attribute name="space-after.optimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.minimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.maximum">0.1em</xsl:attribute> + </xsl:attribute-set> + <xsl:attribute-set name="section.title.level3.properties"> + <xsl:attribute name="space-before.optimum">0.4em</xsl:attribute> + <xsl:attribute name="space-before.minimum">0.4em</xsl:attribute> + <xsl:attribute name="space-before.maximum">0.4em</xsl:attribute> + <xsl:attribute name="font-size"> + <xsl:value-of select="$body.font.master * 1.0"/> + <xsl:text>pt</xsl:text> + </xsl:attribute> + <xsl:attribute name="space-after.optimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.minimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.maximum">0.1em</xsl:attribute> + </xsl:attribute-set> + <xsl:attribute-set name="section.title.level4.properties"> + <xsl:attribute name="space-before.optimum">0.3em</xsl:attribute> + <xsl:attribute name="space-before.minimum">0.3em</xsl:attribute> + <xsl:attribute name="space-before.maximum">0.3em</xsl:attribute> + <xsl:attribute name="font-size"> + <xsl:value-of select="$body.font.master * 0.9"/> + <xsl:text>pt</xsl:text> + </xsl:attribute> + <xsl:attribute name="space-after.optimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.minimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.maximum">0.1em</xsl:attribute> + </xsl:attribute-set> + +<!-- Use code syntax highlighting --> + <xsl:param name="highlight.source" select="1"/> + <xsl:param name="highlight.default.language" select="xml" /> + + <xsl:template match='xslthl:keyword'> + <fo:inline font-weight="bold" color="#7F0055"><xsl:apply-templates/></fo:inline> + </xsl:template> + + <xsl:template match='xslthl:comment'> + <fo:inline font-style="italic" color="#3F5F5F"><xsl:apply-templates/></fo:inline> + </xsl:template> + + <xsl:template match='xslthl:oneline-comment'> + <fo:inline font-style="italic" color="#3F5F5F"><xsl:apply-templates/></fo:inline> + </xsl:template> + + <xsl:template match='xslthl:multiline-comment'> + <fo:inline font-style="italic" color="#3F5FBF"><xsl:apply-templates/></fo:inline> + </xsl:template> + + <xsl:template match='xslthl:tag'> + <fo:inline color="#3F7F7F"><xsl:apply-templates/></fo:inline> + </xsl:template> + + <xsl:template match='xslthl:attribute'> + <fo:inline color="#7F007F"><xsl:apply-templates/></fo:inline> + </xsl:template> + + <xsl:template match='xslthl:value'> + <fo:inline color="#2A00FF"><xsl:apply-templates/></fo:inline> + </xsl:template> + + <xsl:template match='xslthl:string'> + <fo:inline color="#2A00FF"><xsl:apply-templates/></fo:inline> + </xsl:template> + +<!--################################################### + Tables + ################################################### --> + + <!-- Some padding inside tables --> + <xsl:attribute-set name="table.cell.padding"> + <xsl:attribute name="padding-left">4pt</xsl:attribute> + <xsl:attribute name="padding-right">4pt</xsl:attribute> + <xsl:attribute name="padding-top">4pt</xsl:attribute> + <xsl:attribute name="padding-bottom">4pt</xsl:attribute> + </xsl:attribute-set> + +<!-- Only hairlines as frame and cell borders in tables --> + <xsl:param name="table.frame.border.thickness">0.1pt</xsl:param> + <xsl:param name="table.cell.border.thickness">0.1pt</xsl:param> + +<!--################################################### + Labels + ################################################### --> + +<!-- Label Chapters and Sections (numbering) --> + <xsl:param name="chapter.autolabel" select="1"/> + <xsl:param name="section.autolabel" select="1"/> + <xsl:param name="section.autolabel.max.depth" select="1"/> + + <xsl:param name="section.label.includes.component.label" select="1"/> + <xsl:param name="table.footnote.number.format" select="'1'"/> + +<!--################################################### + Programlistings + ################################################### --> + +<!-- Verbatim text formatting (programlistings) --> + <xsl:attribute-set name="monospace.verbatim.properties"> + <xsl:attribute name="font-size"> + <xsl:value-of select="$body.font.small * 1.0"/> + <xsl:text>pt</xsl:text> + </xsl:attribute> + </xsl:attribute-set> + + <xsl:attribute-set name="verbatim.properties"> + <xsl:attribute name="space-before.minimum">1em</xsl:attribute> + <xsl:attribute name="space-before.optimum">1em</xsl:attribute> + <xsl:attribute name="space-before.maximum">1em</xsl:attribute> + <xsl:attribute name="space-after.minimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.optimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.maximum">0.1em</xsl:attribute> + + <xsl:attribute name="border-color">#444444</xsl:attribute> + <xsl:attribute name="border-style">solid</xsl:attribute> + <xsl:attribute name="border-width">0.1pt</xsl:attribute> + <xsl:attribute name="padding-top">0.5em</xsl:attribute> + <xsl:attribute name="padding-left">0.5em</xsl:attribute> + <xsl:attribute name="padding-right">0.5em</xsl:attribute> + <xsl:attribute name="padding-bottom">0.5em</xsl:attribute> + <xsl:attribute name="margin-left">0.5em</xsl:attribute> + <xsl:attribute name="margin-right">0.5em</xsl:attribute> + </xsl:attribute-set> + + <!-- Shade (background) programlistings --> + <xsl:param name="shade.verbatim">1</xsl:param> + <xsl:attribute-set name="shade.verbatim.style"> + <xsl:attribute name="background-color">#F0F0F0</xsl:attribute> + </xsl:attribute-set> + + <xsl:attribute-set name="list.block.spacing"> + <xsl:attribute name="space-before.optimum">0.1em</xsl:attribute> + <xsl:attribute name="space-before.minimum">0.1em</xsl:attribute> + <xsl:attribute name="space-before.maximum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.optimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.minimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.maximum">0.1em</xsl:attribute> + </xsl:attribute-set> + + <xsl:attribute-set name="example.properties"> + <xsl:attribute name="space-before.minimum">0.5em</xsl:attribute> + <xsl:attribute name="space-before.optimum">0.5em</xsl:attribute> + <xsl:attribute name="space-before.maximum">0.5em</xsl:attribute> + <xsl:attribute name="space-after.minimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.optimum">0.1em</xsl:attribute> + <xsl:attribute name="space-after.maximum">0.1em</xsl:attribute> + <xsl:attribute name="keep-together.within-column">always</xsl:attribute> + </xsl:attribute-set> + +<!--################################################### + Title information for Figures, Examples etc. + ################################################### --> + + <xsl:attribute-set name="formal.title.properties" use-attribute-sets="normal.para.spacing"> + <xsl:attribute name="font-weight">normal</xsl:attribute> + <xsl:attribute name="font-style">italic</xsl:attribute> + <xsl:attribute name="font-size"> + <xsl:value-of select="$body.font.master"/> + <xsl:text>pt</xsl:text> + </xsl:attribute> + <xsl:attribute name="hyphenate">false</xsl:attribute> + <xsl:attribute name="space-before.minimum">0.1em</xsl:attribute> + <xsl:attribute name="space-before.optimum">0.1em</xsl:attribute> + <xsl:attribute name="space-before.maximum">0.1em</xsl:attribute> + </xsl:attribute-set> + +<!--################################################### + Callouts + ################################################### --> + +<!-- don't use images for callouts --> + <xsl:param name="callout.graphics">0</xsl:param> + <xsl:param name="callout.unicode">1</xsl:param> + +<!-- Place callout marks at this column in annotated areas --> + <xsl:param name="callout.defaultcolumn">90</xsl:param> + +<!--################################################### + Misc + ################################################### --> + +<!-- Placement of titles --> + <xsl:param name="formal.title.placement"> + figure after + example after + equation before + table before + procedure before + </xsl:param> + +<!-- Format Variable Lists as Blocks (prevents horizontal overflow) --> + <xsl:param name="variablelist.as.blocks">1</xsl:param> + + <xsl:param name="body.start.indent">0pt</xsl:param> + +<!-- Show only Sections up to level 3 in the TOCs --> + <xsl:param name="toc.section.depth">3</xsl:param> + +<!-- Remove "Chapter" from the Chapter titles... --> + <xsl:param name="local.l10n.xml" select="document('')"/> + <l:i18n xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0"> + <l:l10n language="en"> + <l:context name="title-numbered"> + <l:template name="chapter" text="%n. %t"/> + <l:template name="section" text="%n %t"/> + </l:context> + <l:context name="title"> + <l:template name="example" text="Example %n %t"/> + </l:context> + </l:l10n> + </l:i18n> + +<!--################################################### + colored and hyphenated links + ################################################### --> + + <xsl:template match="ulink"> + <fo:basic-link external-destination="{@url}" + xsl:use-attribute-sets="xref.properties" + text-decoration="underline" + color="blue"> + <xsl:choose> + <xsl:when test="count(child::node())=0"> + <xsl:value-of select="@url"/> + </xsl:when> + <xsl:otherwise> + <xsl:apply-templates/> + </xsl:otherwise> + </xsl:choose> + </fo:basic-link> + </xsl:template> + + <xsl:template match="link"> + <fo:basic-link internal-destination="{@linkend}" + xsl:use-attribute-sets="xref.properties" + text-decoration="underline" + color="blue"> + <xsl:choose> + <xsl:when test="count(child::node())=0"> + <xsl:value-of select="@linkend"/> + </xsl:when> + <xsl:otherwise> + <xsl:apply-templates/> + </xsl:otherwise> + </xsl:choose> + </fo:basic-link> + </xsl:template> + +</xsl:stylesheet> \ No newline at end of file diff --git a/spring-integration-reference/styles/pdf/titlepage.xml b/spring-integration-reference/styles/pdf/titlepage.xml new file mode 100644 index 0000000000..dc18e1e0de --- /dev/null +++ b/spring-integration-reference/styles/pdf/titlepage.xml @@ -0,0 +1,101 @@ +<?xml version="1.0" encoding="UTF-8"?> + +<!-- + Licensed to the Apache Software Foundation (ASF) under one + or more contributor license agreements. See the NOTICE file + distributed with this work for additional information + regarding copyright ownership. The ASF licenses this file + to you under the Apache License, Version 2.0 (the + "License"); you may not use this file except in compliance + with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, + software distributed under the License is distributed on an + "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + KIND, either express or implied. See the License for the + specific language governing permissions and limitations + under the License. +--> + +<!DOCTYPE t:templates [ +<!ENTITY hsize0 "10pt"> +<!ENTITY hsize1 "12pt"> +<!ENTITY hsize2 "14.4pt"> +<!ENTITY hsize3 "17.28pt"> +<!ENTITY hsize4 "20.736pt"> +<!ENTITY hsize5 "24.8832pt"> +<!ENTITY hsize0space "7.5pt"> <!-- 0.75 * hsize0 --> +<!ENTITY hsize1space "9pt"> <!-- 0.75 * hsize1 --> +<!ENTITY hsize2space "10.8pt"> <!-- 0.75 * hsize2 --> +<!ENTITY hsize3space "12.96pt"> <!-- 0.75 * hsize3 --> +<!ENTITY hsize4space "15.552pt"> <!-- 0.75 * hsize4 --> +<!ENTITY hsize5space "18.6624pt"> <!-- 0.75 * hsize5 --> +]> +<t:templates xmlns:t="http://nwalsh.com/docbook/xsl/template/1.0" + xmlns:param="http://nwalsh.com/docbook/xsl/template/1.0/param" + xmlns:fo="http://www.w3.org/1999/XSL/Format" + xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> + + <t:titlepage t:element="book" t:wrapper="fo:block"> + <t:titlepage-content t:side="recto"> + <title + t:named-template="division.title" + param:node="ancestor-or-self::book[1]" + text-align="center" + font-size="&hsize5;" + space-before="&hsize5space;" + font-weight="bold" + font-family="{$title.fontset}"/> + <subtitle + text-align="center" + font-size="&hsize4;" + space-before="&hsize4space;" + font-family="{$title.fontset}"/> + + <!-- <corpauthor space-before="0.5em" + font-size="&hsize2;"/> + <authorgroup space-before="0.5em" + font-size="&hsize2;"/> + <author space-before="0.5em" + font-size="&hsize2;"/> --> + + <mediaobject space-before="2em" space-after="2em"/> + <releaseinfo space-before="5em" font-size="&hsize2;"/> + <copyright space-before="1.5em" + font-weight="normal" + font-size="8"/> + <legalnotice space-before="5em" + font-weight="normal" + font-style="italic" + font-size="8"/> + <othercredit space-before="2em" + font-weight="normal" + font-size="8"/> + <pubdate space-before="0.5em"/> + <revision space-before="0.5em"/> + <revhistory space-before="0.5em"/> + <abstract space-before="0.5em" + text-align="start" + margin-left="0.5in" + margin-right="0.5in" + font-family="{$body.fontset}"/> + </t:titlepage-content> + + <t:titlepage-content t:side="verso"> + </t:titlepage-content> + + <t:titlepage-separator> + </t:titlepage-separator> + + <t:titlepage-before t:side="recto"> + </t:titlepage-before> + + <t:titlepage-before t:side="verso"> + </t:titlepage-before> +</t:titlepage> + +<!-- ==================================================================== --> + +</t:templates>