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Header Enricher Docs: JavaConfig and DSL samples

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This commit is contained in:
Gary Russell
2015-10-01 14:47:50 -04:00
committed by Artem Bilan
parent b2d04bf7de
commit 0fd5f5ced8
2 changed files with 62 additions and 12 deletions
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10
src/reference/asciidoc/amqp.adoc
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@@ -217,7 +217,7 @@ The JMS Inbound Channel Adapter is using a JmsDestinationPollingSource under the
The AMQP Inbound Channel Adapter on the other side uses a`SimpleMessageListenerContainer` and is message driven.
In that regard it is more similar to the JMS Message Driven Channel Adapter.
==== Configuring with JavaConfig
==== Configuring with Java Configuration
The following Spring Boot application provides an example of configuring the inbound adapter using Java configuration:
[source, java]
@@ -365,7 +365,7 @@ if you anticipate cases when no `replyTo` property exists in the request message
See the note in <<amqp-inbound-channel-adapter>> about configuring the `listener-container` attribute.
==== Configuring with JavaConfig
==== Configuring with Java Configuration
The following Spring Boot application provides an example of configuring the inbound gateway using Java configuration:
[source, java]
@@ -608,7 +608,7 @@ Using a `return-channel` requires a `RabbitTemplate` with the `mandatory` proper
When using multiple outbound endpoints with returns, a separate `RabbitTemplate` is needed for each endpoint.
=====
==== Configuring with JavaConfig
==== Configuring with Java Configuration
The following Spring Boot application provides an example of configuring the outbound adapter using Java configuration:
[source, java]
@@ -816,7 +816,7 @@ When using multiple outbound endpoints with returns, a separate `RabbitTemplate`
IMPORTANT: The underlying `AmqpTemplate` has a default `replyTimeout` of 5 seconds.
If you require a longer timeout, it must be configured on the `template`.
==== Configuring with JavaConfig
==== Configuring with Java Configuration
The following Spring Boot application provides an example of configuring the outbound gateway using Java configuration:
[source, java]
@@ -941,7 +941,7 @@ There is no "pollable" option for a publish-subscribe-channel; it must be messag
Starting with _version 4.1_ AMQP Backed Message Channels, alongside with `channel-transacted`, support `template-channel-transacted` to separate `transactional` configuration for the `AbstractMessageListenerContainer` and for the `RabbitTemplate`.
Note, previously, the `channel-transacted` was `true` by default, now it changed to `false` as standard default value for the `AbstractMessageListenerContainer`.
==== Configuring with JavaConfig
==== Configuring with Java Configuration
The following provides an example of configuring the channels using Java configuration:

64
src/reference/asciidoc/content-enrichment.adoc
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@@ -110,9 +110,8 @@ as well as point to a Groovy script:
*SpEL Support*
In Spring Integration 2.0 we have introduced the convenience of the http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/expressions.html[Spring Expression Language (SpEL)] to help configure many different components.
The _Header
Enricher_ is one of them.
In Spring Integration 2.0 we have introduced the convenience of the http://docs.spring.io/spring/docs/current/spring-framework-reference/html/expressions.html[Spring Expression Language (SpEL)] to help configure many different components.
The _Header Enricher_ is one of them.
Looking again at the POJO example above, you can see that the computation logic to determine the header value is actually pretty simple.
A natural question would be: "is there a simpler way to accomplish this?".
That is where SpEL shows its true power.
@@ -128,6 +127,54 @@ As you can see, by using SpEL for such simple cases, we no longer have to provid
All we need is the _expression_ attribute configured with a valid SpEL expression.
The 'payload' and 'headers' variables are bound to the SpEL Evaluation Context, giving you full access to the incoming Message.
===== Configuring a Header Enricher with Java Configuration
The following are some examples of Java Configuration for header enrichers:
[source, java]
----
@Bean
@Transformer(inputChannel = "enrichHeadersChannel", outputChannel = "emailChannel")
public HeaderEnricher enrichHeaders() {
Map<String, ? extends HeaderValueMessageProcessor<?>> headersToAdd =
Collections.singletonMap("emailUrl",
new StaticHeaderValueMessageProcessor<>(this.imapUrl));
HeaderEnricher enricher = new HeaderEnricher(headersToAdd);
return enricher;
}
@Bean
@Transformer(inputChannel="enrichHeadersChannel", outputChannel="emailChannel")
public HeaderEnricher enrichHeaders() {
Map<String, HeaderValueMessageProcessor<?>> headersToAdd = new HashMap<>();
headersToAdd.put("emailUrl", new StaticHeaderValueMessageProcessor<String>(this.imapUrl));
Expression expression = new SpelExpressionParser().parseExpression("payload.from[0].toString()");
headersToAdd.put("from",
new ExpressionEvaluatingHeaderValueMessageProcessor<>(expression, String.class));
HeaderEnricher enricher = new HeaderEnricher(headersToAdd);
return enricher;
}
----
The first adds a single literal header.
The second adds two headers - a literal header and one based on a SpEL expression.
===== Configuring a Header Enricher with the Java DSL
The following is an example of Java DSL Configuration for a header enricher:
[source, java]
----
@Bean
public IntegrationFlow enrichHeadersInFlow() {
return f -> f
...
.enrichHeaders(h -> h.header("emailUrl", this.emailUrl)
.headerExpression("from", "payload.from[0].toString()"))
.handle(...);
}
----
[[header-channel-registry]]
===== Header Channel Registry
@@ -263,7 +310,8 @@ For instance the following SpEL expressions (among others) are possible:
<7> Channel where a reply Message is expected.
This is optional; typically the auto-generated temporary reply channel is sufficient._Optional_.
This is optional; typically the auto-generated temporary reply channel is sufficient.
_Optional_.
<8> Channel to which an `ErrorMessage` will be sent if an `Exception` occurs downstream of the `request-channel`.
@@ -275,7 +323,8 @@ _Optional_.
<9> Maximum amount of time in milliseconds to wait when sending a message to the channel, if such channel may block.
For example, a Queue Channel can block until space is available, if its maximum capacity has been reached.
Internally the send timeout is set on the `MessagingTemplate` and ultimately applied when invoking the send operation on the `MessageChannel`.
By default the send timeout is set to '-1', which may cause the send operation on the `MessageChannel`, depending on the implementation, to block indefinitely._Optional_.
By default the send timeout is set to '-1', which may cause the send operation on the `MessageChannel`, depending on the implementation, to block indefinitely.
_Optional_.
<10> Boolean value indicating whether any payload that implements `Cloneable` should be cloned prior to sending the Message to the request chanenl for acquiring the enriching data.
@@ -284,7 +333,8 @@ Default is `false`.
_Optional_.
<11> Allows you to configure a Message Poller if this endpoint is a Polling Consumer._Optional_.
<11> Allows you to configure a Message Poller if this endpoint is a Polling Consumer.
_Optional_.
<12> Each `property` sub-element provides the name of a property (via the mandatory `name` attribute).
@@ -371,7 +421,7 @@ The reply contains a full `User` object, which is ultimately added to the `Map`
_How can I enrich payloads with static information without using a request channel?_
Here is an example that does not use a request channel at all, but solely enriches the message's payload with static values.
But please be aware that the word 'static' is used loosly here.
But please be aware that the word 'static' is used loosely here.
You can still use SpEL expressions for setting those values.
[source,xml]