<?xml version="1.0" encoding="UTF-8"?>
<chapter xmlns="http://docbook.org/ns/docbook" version="5.0"
    xmlns:xlink="http://www.w3.org/1999/xlink"
    xmlns:xi="http://www.w3.org/2001/XInclude"
    xml:id="jms">
  <title>JMS (Java Message Service)</title>

  <section id="jms-introduction">
    <title>Introduction</title>

    <para>Spring provides a JMS integration framework that simplifies the use
    of the JMS API much like Spring's integration does for the JDBC
    API.</para>

    <para>JMS can be roughly divided into two areas of functionality, namely
    the production and consumption of messages. The
    <classname>JmsTemplate</classname> class is used for message production
    and synchronous message reception. For asynchronous reception similar to
    Java EE's message-driven bean style, Spring provides a number of message
    listener containers that are used to create Message-Driven POJOs
    (MDPs).</para>

    <para>The package <literal>org.springframework.jms.core</literal> provides
    the core functionality for using JMS. It contains JMS template classes
    that simplify the use of the JMS by handling the creation and release of
    resources, much like the <classname>JdbcTemplate</classname> does for
    JDBC. The design principle common to Spring template classes is to provide
    helper methods to perform common operations and for more sophisticated
    usage, delegate the essence of the processing task to user implemented
    callback interfaces. The JMS template follows the same design. The classes
    offer various convenience methods for the sending of messages, consuming a
    message synchronously, and exposing the JMS session and message producer
    to the user.</para>

    <para>The package <literal>org.springframework.jms.support</literal>
    provides <classname>JMSException</classname> translation functionality.
    The translation converts the checked <classname>JMSException</classname>
    hierarchy to a mirrored hierarchy of unchecked exceptions. If there are
    any provider specific subclasses of the checked
    <classname>javax.jms.JMSException</classname>, this exception is wrapped
    in the unchecked <classname>UncategorizedJmsException</classname>.</para>

    <para>The package
    <literal>org.springframework.jms.support.converter</literal> provides a
    <interfacename>MessageConverter</interfacename> abstraction to convert
    between Java objects and JMS messages.</para>

    <para>The package
    <literal>org.springframework.jms.support.destination</literal> provides
    various strategies for managing JMS destinations, such as providing a
    service locator for destinations stored in JNDI.</para>

    <para>Finally, the package
    <literal>org.springframework.jms.connection</literal> provides an
    implementation of the <classname>ConnectionFactory</classname> suitable
    for use in standalone applications. It also contains an implementation of
    Spring's <interfacename>PlatformTransactionManager</interfacename> for JMS
    (the cunningly named <classname>JmsTransactionManager</classname>). This
    allows for seamless integration of JMS as a transactional resource into
    Spring's transaction management mechanisms.</para>
  </section>

  <section id="jms-using">
    <title>Using Spring JMS</title>

    <section id="jms-jmstemplate">
      <title><classname>JmsTemplate</classname></title>

      <para>The <classname>JmsTemplate</classname> class is the central class
      in the JMS core package. It simplifies the use of JMS since it handles
      the creation and release of resources when sending or synchronously
      receiving messages.</para>

      <para>Code that uses the <classname>JmsTemplate</classname> only needs
      to implement callback interfaces giving them a clearly defined high
      level contract. The <classname>MessageCreator</classname> callback
      interface creates a message given a
      <interfacename>Session</interfacename> provided by the calling code in
      <classname>JmsTemplate</classname>. In order to allow for more complex
      usage of the JMS API, the callback
      <classname>SessionCallback</classname> provides the user with the JMS
      session and the callback <classname>ProducerCallback</classname> exposes
      a <interfacename>Session</interfacename> and
      <interfacename>MessageProducer</interfacename> pair.</para>

      <para>The JMS API exposes two types of send methods, one that takes
      delivery mode, priority, and time-to-live as Quality of Service (QOS)
      parameters and one that takes no QOS parameters which uses default
      values. Since there are many send methods in
      <classname>JmsTemplate</classname>, the setting of the QOS parameters
      have been exposed as bean properties to avoid duplication in the number
      of send methods. Similarly, the timeout value for synchronous receive
      calls is set using the property
      <classname>setReceiveTimeout</classname>.</para>

      <para>Some JMS providers allow the setting of default QOS values
      administratively through the configuration of the ConnectionFactory.
      This has the effect that a call to
      <classname>MessageProducer</classname>'s send method
      <methodname>send(Destination destination, Message message)</methodname>
      will use different QOS default values than those specified in the JMS
      specification. In order to provide consistent management of QOS values,
      the <classname>JmsTemplate</classname> must therefore be specifically
      enabled to use its own QOS values by setting the boolean property
      <property>isExplicitQosEnabled</property> to
      <literal>true</literal>.</para>

      <note>
        <para>Instances of the <classname>JmsTemplate</classname> class are
        <emphasis>thread-safe once configured</emphasis>. This is important
        because it means that you can configure a single instance of a
        <classname>JmsTemplate</classname> and then safely inject this
        <emphasis>shared</emphasis> reference into multiple collaborators. To
        be clear, the <classname>JmsTemplate</classname> is stateful, in that
        it maintains a reference to a
        <interfacename>ConnectionFactory</interfacename>, but this state is
        <emphasis>not</emphasis> conversational state.</para>
      </note>
    </section>

    <section id="jms-connections">
      <title>Connections</title>

      <para>The <classname>JmsTemplate</classname> requires a reference to a
      <classname>ConnectionFactory</classname>. The
      <classname>ConnectionFactory</classname> is part of the JMS
      specification and serves as the entry point for working with JMS. It is
      used by the client application as a factory to create connections with
      the JMS provider and encapsulates various configuration parameters, many
      of which are vendor specific such as SSL configuration options.</para>

      <para>When using JMS inside an EJB, the vendor provides implementations
      of the JMS interfaces so that they can participate in declarative
      transaction management and perform pooling of connections and sessions.
      In order to use this implementation, Java EE containers typically
      require that you declare a JMS connection factory as a
      <property>resource-ref</property> inside the EJB or servlet deployment
      descriptors. To ensure the use of these features with the
      <classname>JmsTemplate</classname> inside an EJB, the client application
      should ensure that it references the managed implementation of the
      <classname>ConnectionFactory</classname>.</para>

      <section id="jms-caching-resources">
        <title>Caching Messaging Resources</title>

        <para>The standard API involves creating many intermediate objects. To
        send a message the following 'API' walk is performed</para>

        <programlisting>ConnectionFactory-&gt;Connection-&gt;Session-&gt;MessageProducer-&gt;send</programlisting>

        <para>Between the ConnectionFactory and the Send operation there are
        three intermediate objects that are created and destroyed. To optimise
        the resource usage and increase performance two implementations of
        IConnectionFactory are provided.</para>
      </section>

      <section id="jms-connection-factory">
        <title>SingleConnectionFactory</title>

        <para>Spring provides an implementation of the
        <classname>ConnectionFactory</classname> interface,
        <classname>SingleConnectionFactory</classname>, that will return the
        same <classname>Connection</classname> on all
        <methodname>createConnection()</methodname> calls and ignore calls to
        <methodname>close()</methodname>. This is useful for testing and
        standalone environments so that the same connection can be used for
        multiple <classname>JmsTemplate</classname> calls that may span any
        number of transactions. <classname>SingleConnectionFactory</classname>
        takes a reference to a standard
        <classname>ConnectionFactory</classname> that would typically come
        from JNDI.</para>
      </section>

      <section id="jdbc-connection-factory-caching">
        <title>CachingConnectionFactory</title>

        <para>The <classname>CachingConnectionFactory</classname> extends the
        functionality of <classname>SingleConnectionFactory</classname> and
        adds the caching of Sessions, MessageProducers, and MessageConsumers.
        The initial cache size is set to 1, use the property
        <property>SessionCacheSize</property> to increase the number of cached
        sessions. Note that the number of actual cached sessions will be more
        than that number as sessions are cached based on their acknowledgment
        mode, so there can be up to 4 cached session instances when
        <property>SessionCacheSize</property> is set to one, one for each
        AcknowledgementMode. MessageProducers and MessageConsumers are cached
        within their owning session and also take into account the unique
        properties of the producers and consumers when caching.
        MessageProducers are cached based on their destination.
        MessageConsumers are cached based on a key composed of the
        destination, selector, noLocal delivery flag, and the durable
        subscription name (if creating durable consumers).</para>
      </section>
    </section>

    <section id="jms-destinations">
      <title>Destination Management</title>

      <para>Destinations, like ConnectionFactories, are JMS administered
      objects that can be stored and retrieved in JNDI. When configuring a
      Spring application context you can use the JNDI factory class
      <classname>JndiObjectFactoryBean</classname> /
      <literal>&lt;jee:jndi-lookup&gt;</literal> to perform dependency
      injection on your object's references to JMS destinations. However,
      often this strategy is cumbersome if there are a large number of
      destinations in the application or if there are advanced destination
      management features unique to the JMS provider. Examples of such
      advanced destination management would be the creation of dynamic
      destinations or support for a hierarchical namespace of destinations.
      The <classname>JmsTemplate</classname> delegates the resolution of a
      destination name to a JMS destination object to an implementation of the
      interface <classname>DestinationResolver</classname>.
      <classname>DynamicDestinationResolver</classname> is the default
      implementation used by <classname>JmsTemplate</classname> and
      accommodates resolving dynamic destinations. A
      <classname>JndiDestinationResolver</classname> is also provided that
      acts as a service locator for destinations contained in JNDI and
      optionally falls back to the behavior contained in
      <classname>DynamicDestinationResolver</classname>.</para>

      <para>Quite often the destinations used in a JMS application are only
      known at runtime and therefore cannot be administratively created when
      the application is deployed. This is often because there is shared
      application logic between interacting system components that create
      destinations at runtime according to a well-known naming convention.
      Even though the creation of dynamic destinations is not part of the JMS
      specification, most vendors have provided this functionality. Dynamic
      destinations are created with a name defined by the user which
      differentiates them from temporary destinations and are often not
      registered in JNDI. The API used to create dynamic destinations varies
      from provider to provider since the properties associated with the
      destination are vendor specific. However, a simple implementation choice
      that is sometimes made by vendors is to disregard the warnings in the
      JMS specification and to use the <classname>TopicSession</classname>
      method <methodname>createTopic(String topicName)</methodname> or the
      <classname>QueueSession</classname> method
      <methodname>createQueue(String queueName)</methodname> to create a new
      destination with default destination properties. Depending on the vendor
      implementation, <classname>DynamicDestinationResolver</classname> may
      then also create a physical destination instead of only resolving
      one.</para>

      <para>The boolean property <property>pubSubDomain</property> is used to
      configure the <classname>JmsTemplate</classname> with knowledge of what
      JMS domain is being used. By default the value of this property is
      false, indicating that the point-to-point domain, Queues, will be used.
      This property used by <classname>JmsTemplate</classname> determines the
      behavior of dynamic destination resolution via implementations of the
      <interfacename>DestinationResolver</interfacename> interface.</para>

      <para>You can also configure the <classname>JmsTemplate</classname> with
      a default destination via the property
      <property>defaultDestination</property>. The default destination will be
      used with send and receive operations that do not refer to a specific
      destination.</para>
    </section>

    <section id="jms-mdp">
      <title>Message Listener Containers</title>

      <para>One of the most common uses of JMS messages in the EJB world is to
      drive message-driven beans (MDBs). Spring offers a solution to create
      message-driven POJOs (MDPs) in a way that does not tie a user to an EJB
      container. (See <xref linkend="jms-asynchronousMessageReception" />
      for detailed coverage of Spring's MDP support.)</para>

      <para>A message listener container is used to receive messages from a
      JMS message queue and drive the MessageListener that is injected into
      it. The listener container is responsible for all threading of message
      reception and dispatches into the listener for processing. A message
      listener container is the intermediary between an MDP and a messaging
      provider, and takes care of registering to receive messages,
      participating in transactions, resource acquisition and release,
      exception conversion and suchlike. This allows you as an application
      developer to write the (possibly complex) business logic associated with
      receiving a message (and possibly responding to it), and delegates
      boilerplate JMS infrastructure concerns to the framework.</para>

      <para>There are two standard JMS message listener containers packaged
      with Spring, each with its specialised feature set.</para>

      <section id="jms-mdp-simple">
        <title>SimpleMessageListenerContainer</title>

        <para>This message listener container is the simpler of the two
        standard flavors. It creates a fixed number of JMS sessions and
        consumers at startup, registers the listener using the standard JMS
        <methodname>MessageConsumer.setMessageListener()</methodname> method,
        and leaves it up the JMS provider to perform listener callbacks.
        This variant does not allow for dynamic adaption to runtime demands or
        for participation in externally managed transactions. Compatibility-wise,
        it stays very close to the spirit of the standalone JMS specification
        - but is generally not compatible with Java EE's JMS restrictions.</para>
      </section>

      <section id="jms-mdp-default">
        <title>DefaultMessageListenerContainer</title>

        <para>This message listener container is the one used in most cases.
        In contrast to <classname>SimpleMessageListenerContainer</classname>,
        this container variant does allow for dynamic adaption to runtime
        demands and is able to participate in externally managed transactions.
        Each received message is registered with an XA transaction when
        configured with a <classname>JtaTransactionManager</classname>; so
        processing may take advantage of XA transaction semantics. This
        listener container strikes a good balance between low requirements on
        the JMS provider, advanced functionality such as transaction
        participation, and compatibility with Java EE environments.</para>
      </section>
    </section>

    <section id="jms-tx">
      <title>Transaction management</title>

      <para>Spring provides a <classname>JmsTransactionManager</classname>
      that manages transactions for a single JMS
      <classname>ConnectionFactory</classname>. This allows JMS applications
      to leverage the managed transaction features of Spring as described in
      <xref linkend="transaction" />. The
      <classname>JmsTransactionManager</classname> performs local resource
      transactions, binding a JMS Connection/Session pair from the specified
      <classname>ConnectionFactory</classname> to the thread.
      <classname>JmsTemplate</classname> automatically detects such
      transactional resources and operates on them accordingly.</para>

      <para>In a Java EE environment, the
      <classname>ConnectionFactory</classname> will pool Connections and
      Sessions, so those resources are efficiently reused across transactions.
      In a standalone environment, using Spring's
      <classname>SingleConnectionFactory</classname> will result in a shared
      JMS <classname>Connection</classname>, with each transaction having its
      own independent <classname>Session</classname>. Alternatively, consider
      the use of a provider-specific pooling adapter such as ActiveMQ's
      <classname>PooledConnectionFactory</classname> class.</para>

      <para><classname>JmsTemplate</classname> can also be used with the
      <classname>JtaTransactionManager</classname> and an XA-capable JMS
      <classname>ConnectionFactory</classname> for performing distributed
      transactions. Note that this requires the use of a JTA transaction
      manager as well as a properly XA-configured ConnectionFactory! (Check
      your Java EE server's / JMS provider's documentation.)</para>

      <para>Reusing code across a managed and unmanaged transactional
      environment can be confusing when using the JMS API to create a
      <classname>Session</classname> from a <classname>Connection</classname>.
      This is because the JMS API has only one factory method to create a
      <classname>Session</classname> and it requires values for the
      transaction and acknowledgement modes. In a managed environment, setting
      these values is the responsibility of the environment's transactional
      infrastructure, so these values are ignored by the vendor's wrapper to
      the JMS Connection. When using the <classname>JmsTemplate</classname> in
      an unmanaged environment you can specify these values through the use of
      the properties <literal>sessionTransacted</literal> and
      <literal>sessionAcknowledgeMode</literal>. When using a
      <classname>PlatformTransactionManager</classname> with
      <classname>JmsTemplate</classname>, the template will always be given a
      transactional JMS <classname>Session</classname>.</para>
    </section>
  </section>

  <section id="jms-sending">
    <title>Sending a <interfacename>Message</interfacename></title>

    <para>The <classname>JmsTemplate</classname> contains many convenience
    methods to send a message. There are send methods that specify the
    destination using a <classname>javax.jms.Destination</classname> object
    and those that specify the destination using a string for use in a JNDI
    lookup. The send method that takes no destination argument uses the
    default destination. Here is an example that sends a message to a queue
    using the 1.0.2 implementation.</para>

    <programlisting language="java">import javax.jms.ConnectionFactory;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.Queue;
import javax.jms.Session;

import org.springframework.jms.core.MessageCreator;
import org.springframework.jms.core.JmsTemplate;

public class JmsQueueSender {

    private JmsTemplate jmsTemplate;
    private Queue queue;

    public void setConnectionFactory(ConnectionFactory cf) {
        this.jmsTemplate = new JmsTemplate(cf);
    }

    public void setQueue(Queue queue) {
        this.queue = queue;
    }

    public void simpleSend() {
        this.jmsTemplate.send(this.queue, new MessageCreator() {
            public Message createMessage(Session session) throws JMSException {
              return session.createTextMessage("hello queue world");
            }
        });
    }
}</programlisting>

    <para>This example uses the <classname>MessageCreator</classname> callback
    to create a text message from the supplied <classname>Session</classname>
    object. The <classname>JmsTemplate</classname> is constructed by passing a
    reference to a <classname>ConnectionFactory</classname>. As an alternative,
    a zero argument constructor and <property>connectionFactory</property>
    is provided and can be used for constructing the instance in JavaBean style
    (using a BeanFactory or plain Java code). Alternatively, consider deriving
    from Spring's <classname>JmsGatewaySupport</classname> convenience base class,
    which provides pre-built bean properties for JMS configuration.</para>

    <para>The method <methodname>send(String destinationName, MessageCreator
    creator)</methodname> lets you send a message using the string name of
    the destination. If these names are registered in JNDI, you should set the
    <property>destinationResolver</property> property of the template to an
    instance of <classname>JndiDestinationResolver</classname>.</para>

    <para>If you created the <classname>JmsTemplate</classname> and specified
    a default destination, the <methodname>send(MessageCreator c)</methodname>
    sends a message to that destination.</para>

    <section id="jms-msg-conversion">
      <title>Using Message Converters</title>

      <para>In order to facilitate the sending of domain model objects, the
      <classname>JmsTemplate</classname> has various send methods that take a
      Java object as an argument for a message's data content. The overloaded
      methods <methodname>convertAndSend()</methodname> and
      <methodname>receiveAndConvert()</methodname> in
      <classname>JmsTemplate</classname> delegate the conversion process to an
      instance of the <literal>MessageConverter</literal> interface. This
      interface defines a simple contract to convert between Java objects and
      JMS messages. The default implementation
      <classname>SimpleMessageConverter</classname> supports conversion
      between <classname>String</classname> and
      <classname>TextMessage</classname>, <classname>byte[]</classname> and
      <classname>BytesMesssage</classname>, and
      <classname>java.util.Map</classname> and
      <classname>MapMessage</classname>. By using the converter, you and your
      application code can focus on the business object that is being sent or
      received via JMS and not be concerned with the details of how it is
      represented as a JMS message.</para>

      <para>The sandbox currently includes a
      <classname>MapMessageConverter</classname> which uses reflection to
      convert between a JavaBean and a <classname>MapMessage</classname>.
      Other popular implementation choices you might implement yourself are
      Converters that use an existing XML marshalling package, such as JAXB,
      Castor, XMLBeans, or XStream, to create a
      <interfacename>TextMessage</interfacename> representing the
      object.</para>

      <para>To accommodate the setting of a message's properties, headers, and
      body that can not be generically encapsulated inside a converter class,
      the <interfacename>MessagePostProcessor</interfacename> interface gives
      you access to the message after it has been converted, but before it is
      sent. The example below demonstrates how to modify a message header and
      a property after a <interfacename>java.util.Map</interfacename> is
      converted to a message.</para>

      <programlisting language="java">public void sendWithConversion() {
    Map map = new HashMap();
    map.put("Name", "Mark");
    map.put("Age", new Integer(47));
    jmsTemplate.convertAndSend("testQueue", map, new MessagePostProcessor() {
        public Message postProcessMessage(Message message) throws JMSException {
            message.setIntProperty("AccountID", 1234);
            message.setJMSCorrelationID("123-00001");
            return message;
        }
    });
}</programlisting>

      <para>This results in a message of the form:</para>

      <programlisting>MapMessage={
    Header={
        ... standard headers ...
        CorrelationID={123-00001}
    }
    Properties={
        AccountID={Integer:1234}
    }
    Fields={
        Name={String:Mark}
        Age={Integer:47}
    } 
}</programlisting>
    </section>

    <section id="jms-callbacks">
      <title><interfacename>SessionCallback</interfacename> and
      <interfacename>ProducerCallback</interfacename></title>

      <para>While the send operations cover many common usage scenarios, there
      are cases when you want to perform multiple operations on a JMS
      <interfacename>Session</interfacename> or
      <interfacename>MessageProducer</interfacename>. The
      <interfacename>SessionCallback</interfacename> and
      <interfacename>ProducerCallback</interfacename> expose the JMS
      <interfacename>Session</interfacename> and
      <interfacename>Session</interfacename> /
      <interfacename>MessageProducer</interfacename> pair respectively. The
      <methodname>execute()</methodname> methods on
      <classname>JmsTemplate</classname> execute these callback
      methods.</para>
    </section>
  </section>

  <section id="jms-receiving">
    <title>Receiving a message</title>

    <section id="jms-receiving-sync">
      <title>Synchronous Reception</title>

      <para>While JMS is typically associated with asynchronous processing, it
      is possible to consume messages synchronously. The overloaded
      <methodname>receive(..)</methodname> methods provide this functionality.
      During a synchronous receive, the calling thread blocks until a message
      becomes available. This can be a dangerous operation since the calling
      thread can potentially be blocked indefinitely. The property
      <property>receiveTimeout</property> specifies how long the receiver
      should wait before giving up waiting for a message.</para>
    </section>

    <section id="jms-asynchronousMessageReception">
      <title>Asynchronous Reception - Message-Driven POJOs</title>

      <para>In a fashion similar to a Message-Driven Bean (MDB) in the EJB
      world, the Message-Driven POJO (MDP) acts as a receiver for JMS
      messages. The one restriction (but see also below for the discussion of
      the <classname>MessageListenerAdapter</classname> class) on an MDP is
      that it must implement the
      <interfacename>javax.jms.MessageListener</interfacename> interface.
      Please also be aware that in the case where your POJO will be receiving
      messages on multiple threads, it is important to ensure that your
      implementation is thread-safe.</para>

      <para>Below is a simple implementation of an MDP:</para>

      <programlisting language="java">import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;

public class ExampleListener implements MessageListener {

    public void onMessage(Message message) {
        if (message instanceof TextMessage) {
            try {
                System.out.println(((TextMessage) message).getText());
            }
            catch (JMSException ex) {
                throw new RuntimeException(ex);
            }
        }
        else {
            throw new IllegalArgumentException("Message must be of type TextMessage");
        }
    }
}</programlisting>

      <para>Once you've implemented your
      <interfacename>MessageListener</interfacename>, it's time to create a
      message listener container.</para>

      <para>Find below an example of how to define and configure one of the
      message listener containers that ships with Spring (in this case the
      <classname>DefaultMessageListenerContainer</classname>).</para>

      <programlisting language="xml"><lineannotation>&lt;!-- this is the Message Driven POJO (MDP) --&gt;</lineannotation>
&lt;bean id="messageListener" class="jmsexample.ExampleListener" /&gt;

<lineannotation>&lt;!-- and this is the message listener container --&gt;</lineannotation>
&lt;bean id="jmsContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer"&gt;
    &lt;property name="connectionFactory" ref="connectionFactory"/&gt;
    &lt;property name="destination" ref="destination"/&gt;
    <emphasis role="bold">&lt;property name="messageListener" ref="messageListener" /&gt;</emphasis>
&lt;/bean&gt;</programlisting>

      <para>Please refer to the Spring Javadoc of the various message listener
      containers for a full description of the features supported by each
      implementation.</para>
    </section>

    <section id="jms-receiving-async-session-aware-message-listener">
      <title>The <interfacename>SessionAwareMessageListener</interfacename>
      interface</title>

      <para>The <interfacename>SessionAwareMessageListener</interfacename>
      interface is a Spring-specific interface that provides a similar
      contract to the JMS <interfacename>MessageListener</interfacename>
      interface, but also provides the message handling method with access to
      the JMS <interfacename>Session</interfacename> from which the
      <interfacename>Message</interfacename> was received.</para>

      <programlisting language="java">package org.springframework.jms.listener;

public interface SessionAwareMessageListener {

    void onMessage(Message message, Session session) <emphasis role="bold">throws JMSException</emphasis>;
}</programlisting>

      <para>You can choose to have your MDPs implement this interface (in
      preference to the standard JMS
      <interfacename>MessageListener</interfacename> interface) if you want
      your MDPs to be able to respond to any received messages (using the
      <interfacename>Session</interfacename> supplied in the
      <literal>onMessage(Message, Session)</literal> method). All of the
      message listener container implementations that ship with Spring have
      support for MDPs that implement either the
      <interfacename>MessageListener</interfacename> or
      <interfacename>SessionAwareMessageListener</interfacename> interface.
      Classes that implement the
      <interfacename>SessionAwareMessageListener</interfacename> come with the
      caveat that they are then tied to Spring through the interface. The
      choice of whether or not to use it is left entirely up to you as an
      application developer or architect.</para>

      <para>Please note that the <literal>'onMessage(..)'</literal> method of
      the <interfacename>SessionAwareMessageListener</interfacename> interface
      throws <classname>JMSException</classname>. In contrast to the standard
      JMS <interfacename>MessageListener</interfacename> interface, when using
      the <interfacename>SessionAwareMessageListener</interfacename>
      interface, it is the responsibility of the client code to handle any
      exceptions thrown.</para>
    </section>

    <section id="jms-receiving-async-message-listener-adapter">
      <title>The <classname>MessageListenerAdapter</classname></title>

      <para>The <classname>MessageListenerAdapter</classname> class is the
      final component in Spring's asynchronous messaging support: in a
      nutshell, it allows you to expose almost <emphasis>any</emphasis> class
      as a MDP (there are of course some constraints).</para>

      <para>Consider the following interface definition. Notice that although
      the interface extends neither the
      <interfacename>MessageListener</interfacename> nor
      <interfacename>SessionAwareMessageListener</interfacename> interfaces,
      it can still be used as a MDP via the use of the
      <classname>MessageListenerAdapter</classname> class. Notice also how the
      various message handling methods are strongly typed according to the
      <emphasis>contents</emphasis> of the various
      <interfacename>Message</interfacename> types that they can receive and
      handle.</para>

      <programlisting language="java">public interface MessageDelegate {

    void handleMessage(String message);

    void handleMessage(Map message);

    void handleMessage(byte[] message);

    void handleMessage(Serializable message);
}</programlisting>

      <programlisting language="java">public class DefaultMessageDelegate implements MessageDelegate {
    <lineannotation>// implementation elided for clarity...</lineannotation>
}</programlisting>

      <para>In particular, note how the above implementation of the
      <interfacename>MessageDelegate</interfacename> interface (the above
      <classname>DefaultMessageDelegate</classname> class) has
      <emphasis>no</emphasis> JMS dependencies at all. It truly is a POJO that
      we will make into an MDP via the following configuration.</para>

      <programlisting language="xml"><lineannotation>&lt;!-- this is the Message Driven POJO (MDP) --&gt;</lineannotation>
<emphasis role="bold">&lt;bean id="messageListener" class="org.springframework.jms.listener.adapter.MessageListenerAdapter"&gt;
    &lt;constructor-arg&gt;
        &lt;bean class="jmsexample.DefaultMessageDelegate"/&gt;
    &lt;/constructor-arg&gt;
&lt;/bean&gt;</emphasis>

<lineannotation>&lt;!-- and this is the message listener container... --&gt;</lineannotation>
&lt;bean id="jmsContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer"&gt;
    &lt;property name="connectionFactory" ref="connectionFactory"/&gt;
    &lt;property name="destination" ref="destination"/&gt;
    <emphasis role="bold">&lt;property name="messageListener" ref="messageListener" /&gt;</emphasis>
&lt;/bean&gt;</programlisting>

      <para>Below is an example of another MDP that can only handle the
      receiving of JMS <interfacename>TextMessage</interfacename> messages.
      Notice how the message handling method is actually called
      <literal>'receive'</literal> (the name of the message handling method in
      a <classname>MessageListenerAdapter</classname> defaults to
      <literal>'handleMessage'</literal>), but it is configurable (as you will
      see below). Notice also how the <literal>'receive(..)'</literal> method
      is strongly typed to receive and respond only to JMS
      <interfacename>TextMessage</interfacename> messages.</para>

      <programlisting language="java">public interface TextMessageDelegate {

    void receive(TextMessage message);
}</programlisting>

      <programlisting language="java">public class DefaultTextMessageDelegate implements TextMessageDelegate {
    <lineannotation>// implementation elided for clarity...</lineannotation>
}</programlisting>

      <para>The configuration of the attendant
      <classname>MessageListenerAdapter</classname> would look like
      this:</para>

      <programlisting language="xml">&lt;bean id="messageListener" class="org.springframework.jms.listener.adapter.MessageListenerAdapter"&gt;
    &lt;constructor-arg&gt;
        &lt;bean class="jmsexample.DefaultTextMessageDelegate"/&gt;
    &lt;/constructor-arg&gt;
    &lt;property name="defaultListenerMethod" value="receive"/&gt;
    <lineannotation>&lt;!-- we <emphasis role="bold">don't</emphasis> want automatic message context extraction --&gt;</lineannotation>
    &lt;property name="messageConverter"&gt;
        &lt;null/&gt;
    &lt;/property&gt;
&lt;/bean&gt;</programlisting>

      <para>Please note that if the above <literal>'messageListener'</literal>
      receives a JMS <interfacename>Message</interfacename> of a type other
      than <interfacename>TextMessage</interfacename>, an
      <classname>IllegalStateException</classname> will be thrown (and
      subsequently swallowed). Another of the capabilities of the
      <classname>MessageListenerAdapter</classname> class is the ability to
      automatically send back a response
      <interfacename>Message</interfacename> if a handler method returns a
      non-void value. Consider the interface and class:</para>

      <programlisting language="java">public interface ResponsiveTextMessageDelegate {

    <lineannotation><emphasis role="bold">// notice the return type...</emphasis></lineannotation>
    String receive(TextMessage message);
}</programlisting>

      <programlisting language="java">public class DefaultResponsiveTextMessageDelegate implements ResponsiveTextMessageDelegate {
    <lineannotation>// implementation elided for clarity...</lineannotation>
}</programlisting>

      <para>If the above
      <classname>DefaultResponsiveTextMessageDelegate</classname> is used in
      conjunction with a <classname>MessageListenerAdapter</classname> then
      any non-null value that is returned from the execution of the
      <literal>'receive(..)'</literal> method will (in the default
      configuration) be converted into a
      <interfacename>TextMessage</interfacename>. The resulting
      <interfacename>TextMessage</interfacename> will then be sent to the
      <interfacename>Destination</interfacename> (if one exists) defined in
      the JMS Reply-To property of the original
      <interfacename>Message</interfacename>, or the default
      <interfacename>Destination</interfacename> set on the
      <classname>MessageListenerAdapter</classname> (if one has been
      configured); if no <interfacename>Destination</interfacename> is found
      then an <classname>InvalidDestinationException</classname> will be
      thrown (and please note that this exception <emphasis>will
      not</emphasis> be swallowed and <emphasis>will</emphasis> propagate up
      the call stack).</para>
    </section>

    <section id="jms-tx-participation">
      <title>Processing messages within transactions</title>

      <para>Invoking a message listener within a transaction only requires
      reconfiguration of the listener container.</para>

      <para>Local resource transactions can simply be activated through the
      <literal>sessionTransacted</literal> flag on the listener container
      definition. Each message listener invocation will then operate within an
      active JMS transaction, with message reception rolled back in case of
      listener execution failure. Sending a response message (via
      <interfacename>SessionAwareMessageListener</interfacename>) will be part
      of the same local transaction, but any other resource operations (such
      as database access) will operate independently. This usually requires
      duplicate message detection in the listener implementation, covering the
      case where database processing has committed but message processing
      failed to commit.</para>

      <programlisting language="xml">&lt;bean id="jmsContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer"&gt;
    &lt;property name="connectionFactory" ref="connectionFactory"/&gt;
    &lt;property name="destination" ref="destination"/&gt;
    &lt;property name="messageListener" ref="messageListener"/&gt;
    <emphasis role="bold">&lt;property name="sessionTransacted" value="true"/&gt;</emphasis>
&lt;/bean&gt;</programlisting>

      <para>For participating in an externally managed transaction, you will
      need to configure a transaction manager and use a listener container
      which supports externally managed transactions: typically
      <classname>DefaultMessageListenerContainer</classname>.</para>

      <para>To configure a message listener container for XA transaction
      participation, you'll want to configure a
      <classname>JtaTransactionManager</classname> (which, by default,
      delegates to the Java EE server's transaction subsystem). Note that the
      underlying JMS ConnectionFactory needs to be XA-capable and properly
      registered with your JTA transaction coordinator! (Check your Java EE
      server's configuration of JNDI resources.) This allows message reception
      as well as e.g. database access to be part of the same transaction (with
      unified commit semantics, at the expense of XA transaction log
      overhead).</para>

      <programlisting language="xml">&lt;bean id="transactionManager" class="org.springframework.transaction.jta.JtaTransactionManager"/&gt;
</programlisting>

      <para>Then you just need to add it to our earlier container
      configuration. The container will take care of the rest.</para>

      <programlisting language="xml">&lt;bean id="jmsContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer"&gt;
    &lt;property name="connectionFactory" ref="connectionFactory"/&gt;
    &lt;property name="destination" ref="destination"/&gt;
    &lt;property name="messageListener" ref="messageListener"/&gt;
    <emphasis role="bold">&lt;property name="transactionManager" ref="transactionManager"/&gt;</emphasis>
&lt;/bean&gt;</programlisting>
    </section>
  </section>

  <section id="jms-jca-message-endpoint-manager">
    <title>Support for JCA Message Endpoints</title>

    <para>Beginning with version 2.5, Spring also provides support for a
    JCA-based <interfacename>MessageListener</interfacename> container. The
    <classname>JmsMessageEndpointManager</classname> will attempt to
    automatically determine the <interfacename>ActivationSpec</interfacename>
    class name from the provider's
    <interfacename>ResourceAdapter</interfacename> class name. Therefore, it
    is typically possible to just provide Spring's generic
    <classname>JmsActivationSpecConfig</classname> as shown in the following
    example.</para>

    <programlisting language="xml">&lt;bean class="org.springframework.jms.listener.endpoint.JmsMessageEndpointManager"&gt;
    &lt;property name="resourceAdapter" ref="resourceAdapter"/&gt;
    &lt;property name="activationSpecConfig"&gt;
        &lt;bean class="org.springframework.jms.listener.endpoint.JmsActivationSpecConfig"&gt;
            &lt;property name="destinationName" value="myQueue"/&gt;
        &lt;/bean&gt;
    &lt;/property&gt;
    &lt;property name="messageListener" ref="myMessageListener"/&gt;
&lt;/bean&gt;</programlisting>

    <para>Alternatively, you may set up a
    <classname>JmsMessageEndpointManager</classname> with a given
    <interfacename>ActivationSpec</interfacename> object. The
    <interfacename>ActivationSpec</interfacename> object may also come from a
    JNDI lookup (using <literal>&lt;jee:jndi-lookup&gt;</literal>).</para>

    <programlisting language="xml">&lt;bean class="org.springframework.jms.listener.endpoint.JmsMessageEndpointManager"&gt;
    &lt;property name="resourceAdapter" ref="resourceAdapter"/&gt;
    &lt;property name="activationSpec"&gt;
        &lt;bean class="org.apache.activemq.ra.ActiveMQActivationSpec"&gt;
            &lt;property name="destination" value="myQueue"/&gt;
            &lt;property name="destinationType" value="javax.jms.Queue"/&gt;
        &lt;/bean&gt;
    &lt;/property&gt;
    &lt;property name="messageListener" ref="myMessageListener"/&gt;
&lt;/bean&gt;</programlisting>

    <para>Using Spring's <classname>ResourceAdapterFactoryBean</classname>,
    the target <interfacename>ResourceAdapter</interfacename> may be
    configured locally as depicted in the following example.</para>

    <programlisting language="xml">&lt;bean id="resourceAdapter" class="org.springframework.jca.support.ResourceAdapterFactoryBean"&gt;
    &lt;property name="resourceAdapter"&gt;
        &lt;bean class="org.apache.activemq.ra.ActiveMQResourceAdapter"&gt;
            &lt;property name="serverUrl" value="tcp://localhost:61616"/&gt;
        &lt;/bean&gt;
    &lt;/property&gt;
    &lt;property name="workManager"&gt;
        &lt;bean class="org.springframework.jca.work.SimpleTaskWorkManager"/&gt;
    &lt;/property&gt;
&lt;/bean&gt;</programlisting>

    <para>The specified <interfacename>WorkManager</interfacename> may also
    point to an environment-specific thread pool - typically through
    <classname>SimpleTaskWorkManager's</classname> "asyncTaskExecutor"
    property. Consider defining a shared thread pool for all your
    <interfacename>ResourceAdapter</interfacename> instances if you happen to
    use multiple adapters.</para>

    <para>In some environments (e.g. WebLogic 9 or above), the entire
    <interfacename>ResourceAdapter</interfacename> object may be obtained from
    JNDI instead (using <literal>&lt;jee:jndi-lookup&gt;</literal>). The
    Spring-based message listeners can then interact with the server-hosted
    <interfacename>ResourceAdapter</interfacename>, also using the server's
    built-in <interfacename>WorkManager</interfacename>.</para>

    <para>Please consult the JavaDoc for
    <classname>JmsMessageEndpointManager</classname>,
    <classname>JmsActivationSpecConfig</classname>, and
    <classname>ResourceAdapterFactoryBean</classname> for more details.</para>

    <para>Spring also provides a generic JCA message endpoint manager which is
    not tied to JMS:
    <classname>org.springframework.jca.endpoint.GenericMessageEndpointManager</classname>.
    This component allows for using any message listener type (e.g. a CCI
    MessageListener) and any provider-specific ActivationSpec object. Check
    out your JCA provider's documentation to find out about the actual
    capabilities of your connector, and consult
    <classname>GenericMessageEndpointManager</classname>'s JavaDoc for the
    Spring-specific configuration details.</para>

    <note>
      <para>JCA-based message endpoint management is very analogous to EJB 2.1
      Message-Driven Beans; it uses the same underlying resource provider
      contract. Like with EJB 2.1 MDBs, any message listener interface
      supported by your JCA provider can be used in the Spring context as
      well. Spring nevertheless provides explicit 'convenience' support for
      JMS, simply because JMS is the most common endpoint API used with the
      JCA endpoint management contract.</para>
    </note>
  </section>

  <section id="jms-namespace">
    <title>JMS Namespace Support</title>

    <para>Spring 2.5 introduces an XML namespace for simplifying JMS
    configuration. To use the JMS namespace elements you will need to
    reference the JMS schema:</para>

    <programlisting language="xml">&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       <emphasis role="bold">xmlns:jms="http://www.springframework.org/schema/jms"</emphasis>
       xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
<emphasis role="bold">http://www.springframework.org/schema/jms http://www.springframework.org/schema/jms/spring-jms-3.0.xsd"</emphasis>&gt;

<lineannotation>&lt;!-- <literal>&lt;bean/&gt;</literal> definitions here --&gt;</lineannotation>

&lt;/beans&gt;</programlisting>

    <para>The namespace consists of two top-level elements:
    <literal>&lt;listener-container/&gt;</literal> and
    <literal>&lt;jca-listener-container/&gt;</literal> both of which may
    contain one or more <literal>&lt;listener/&gt;</literal> child elements.
    Here is an example of a basic configuration for two listeners.</para>

    <programlisting language="xml">&lt;jms:listener-container&gt;

    &lt;jms:listener destination="queue.orders" ref="orderService" method="placeOrder"/&gt;

    &lt;jms:listener destination="queue.confirmations" ref="confirmationLogger" method="log"/&gt;

&lt;/jms:listener-container&gt;</programlisting>

    <para>The example above is equivalent to creating two distinct listener
    container bean definitions and two distinct
    <classname>MessageListenerAdapter</classname> bean definitions as
    demonstrated in <xref linkend="jms-receiving-async-message-listener-adapter" />.
    In addition to the attributes shown above, the <literal>listener</literal> element
    may contain several optional ones. The following table describes all available
    attributes:</para>

    <table id="jms-namespace-listener-tbl">
      <title>Attributes of the JMS <literal>&lt;listener&gt;</literal>
      element</title>

      <tgroup cols="2">
        <colspec colname="c1" colwidth="2*" />

        <colspec colname="c2" colwidth="4*" />

        <thead>
          <row>
            <entry>Attribute</entry>

            <entry>Description</entry>
          </row>
        </thead>

        <tbody>
          <row>
            <entry>id</entry>

            <entry><para>A bean name for the hosting listener container. If
            not specified, a bean name will be automatically
            generated.</para></entry>
          </row>

          <row>
            <entry>destination <emphasis
            role="bold">(required)</emphasis></entry>

            <entry><para>The destination name for this listener, resolved
            through the <interfacename>DestinationResolver</interfacename>
            strategy.</para></entry>
          </row>

          <row>
            <entry>ref <emphasis role="bold">(required)</emphasis></entry>

            <entry><para>The bean name of the handler object.</para></entry>
          </row>

          <row>
            <entry>method</entry>

            <entry><para>The name of the handler method to invoke. If the
            <literal>ref</literal> points to a
            <interfacename>MessageListener</interfacename> or Spring
            <interfacename>SessionAwareMessageListener</interfacename>, this
            attribute may be omitted.</para></entry>
          </row>

          <row>
            <entry>response-destination</entry>

            <entry><para>The name of the default response destination to send
            response messages to. This will be applied in case of a request
            message that does not carry a "JMSReplyTo" field. The type of this
            destination will be determined by the listener-container's
            "destination-type" attribute. Note: This only applies to a
            listener method with a return value, for which each result object
            will be converted into a response message.</para></entry>
          </row>

          <row>
            <entry>subscription</entry>

            <entry><para>The name of the durable subscription, if
            any.</para></entry>
          </row>

          <row>
            <entry>selector</entry>

            <entry><para>An optional message selector for this
            listener.</para></entry>
          </row>
        </tbody>
      </tgroup>
    </table>

    <para>The <literal>&lt;listener-container/&gt;</literal> element also
    accepts several optional attributes. This allows for customization of the
    various strategies (for example, <property>taskExecutor</property> and
    <property>destinationResolver</property>) as well as basic JMS settings
    and resource references. Using these attributes, it is possible to define
    highly-customized listener containers while still benefiting from the
    convenience of the namespace.</para>

    <programlisting language="xml">&lt;jms:listener-container connection-factory="myConnectionFactory"
                        task-executor="myTaskExecutor"
                        destination-resolver="myDestinationResolver"
                        transaction-manager="myTransactionManager"
                        concurrency="10"&gt;

    &lt;jms:listener destination="queue.orders" ref="orderService" method="placeOrder"/&gt;

    &lt;jms:listener destination="queue.confirmations" ref="confirmationLogger" method="log"/&gt;

&lt;/jms:listener-container&gt;</programlisting>

    <para>The following table describes all available attributes. Consult the
    class-level Javadoc of the
    <classname>AbstractMessageListenerContainer</classname> and its concrete
    subclasses for more details on the individual properties. The Javadoc also
    provides a discussion of transaction choices and message redelivery
    scenarios.</para>

    <table id="jms-namespace-listener-container-tbl">
      <title>Attributes of the JMS
      <literal>&lt;listener-container&gt;</literal> element</title>

      <tgroup cols="2">
        <colspec colname="c1" colwidth="2*" />

        <colspec colname="c2" colwidth="4*" />

        <thead>
          <row>
            <entry>Attribute</entry>

            <entry>Description</entry>
          </row>
        </thead>

        <tbody>
          <row>
            <entry>container-type</entry>

            <entry><para>The type of this listener container. Available
            options are: <literal>default</literal>,
            <literal>simple</literal>, <literal>default102</literal>, or
            <literal>simple102</literal> (the default value is
            <literal>'default'</literal>).</para></entry>
          </row>

          <row>
            <entry>connection-factory</entry>

            <entry><para>A reference to the JMS
            <interfacename>ConnectionFactory</interfacename> bean (the default
            bean name is
            <literal>'connectionFactory'</literal>).</para></entry>
          </row>

          <row>
            <entry>task-executor</entry>

            <entry><para>A reference to the Spring
            <interfacename>TaskExecutor</interfacename> for the JMS listener
            invokers.</para></entry>
          </row>

          <row>
            <entry>destination-resolver</entry>

            <entry><para>A reference to the
            <interfacename>DestinationResolver</interfacename> strategy for
            resolving JMS
            <interfacename>Destinations</interfacename>.</para></entry>
          </row>

          <row>
            <entry>message-converter</entry>

            <entry><para>A reference to the
            <interfacename>MessageConverter</interfacename> strategy for
            converting JMS Messages to listener method arguments. Default is a
            <classname>SimpleMessageConverter</classname>.</para></entry>
          </row>

          <row>
            <entry>destination-type</entry>

            <entry><para>The JMS destination type for this listener:
            <literal>queue</literal>, <literal>topic</literal> or
            <literal>durableTopic</literal>. The default is
            <literal>queue</literal>.</para></entry>
          </row>

          <row>
            <entry>client-id</entry>

            <entry><para>The JMS client id for this listener container. Needs
            to be specified when using durable subscriptions.</para></entry>
          </row>

          <row>
            <entry>cache</entry>

            <entry><para>The cache level for JMS resources:
            <literal>none</literal>, <literal>connection</literal>,
            <literal>session</literal>, <literal>consumer</literal> or
            <literal>auto</literal>. By default (<literal>auto</literal>), the
            cache level will effectively be "consumer", unless an external
            transaction manager has been specified - in which case the
            effective default will be <literal>none</literal> (assuming
            Java EE-style transaction management where the given
            ConnectionFactory is an XA-aware pool).</para></entry>
          </row>

          <row>
            <entry>acknowledge</entry>

            <entry><para>The native JMS acknowledge mode:
            <literal>auto</literal>, <literal>client</literal>,
            <literal>dups-ok</literal> or <literal>transacted</literal>. A
            value of <literal>transacted</literal> activates a locally
            transacted <interfacename>Session</interfacename>. As an
            alternative, specify the <literal>transaction-manager</literal>
            attribute described below. Default is
            <literal>auto</literal>.</para></entry>
          </row>

          <row>
            <entry>transaction-manager</entry>

            <entry><para>A reference to an external
            <interfacename>PlatformTransactionManager</interfacename>
            (typically an XA-based transaction coordinator, e.g. Spring's
            <classname>JtaTransactionManager</classname>). If not specified,
            native acknowledging will be used (see "acknowledge"
            attribute).</para></entry>
          </row>

          <row>
            <entry>concurrency</entry>

            <entry><para>The number of concurrent sessions/consumers to start
            for each listener. Can either be a simple number indicating the
            maximum number (e.g. "5") or a range indicating the lower as well
            as the upper limit (e.g. "3-5"). Note that a specified minimum is
            just a hint and might be ignored at runtime. Default is 1; keep
            concurrency limited to 1 in case of a topic listener or if queue
            ordering is important; consider raising it for general
            queues.</para></entry>
          </row>

          <row>
            <entry>prefetch</entry>

            <entry><para>The maximum number of messages to load into a single
            session. Note that raising this number might lead to starvation of
            concurrent consumers!</para></entry>
          </row>
        </tbody>
      </tgroup>
    </table>

    <para>Configuring a JCA-based listener container with the "jms" schema
    support is very similar.</para>

    <programlisting language="xml">&lt;jms:jca-listener-container resource-adapter="myResourceAdapter"
                            destination-resolver="myDestinationResolver"
                            transaction-manager="myTransactionManager"
                            concurrency="10"&gt;

    &lt;jms:listener destination="queue.orders" ref="myMessageListener"/&gt;

&lt;/jms:jca-listener-container&gt;</programlisting>

    <para>The available configuration options for the JCA variant are
    described in the following table:</para>

    <table id="jms-namespace-jca-listener-container-tbl">
      <title>Attributes of the JMS
      <literal>&lt;jca-listener-container/&gt;</literal> element</title>

      <tgroup cols="2">
        <colspec colname="c1" colwidth="2*" />

        <colspec colname="c2" colwidth="4*" />

        <thead>
          <row>
            <entry>Attribute</entry>

            <entry>Description</entry>
          </row>
        </thead>

        <tbody>
          <row>
            <entry>resource-adapter</entry>

            <entry><para>A reference to the JCA
            <interfacename>ResourceAdapter</interfacename> bean (the default
            bean name is <literal>'resourceAdapter'</literal>).</para></entry>
          </row>

          <row>
            <entry>activation-spec-factory</entry>

            <entry><para>A reference to the
            <interfacename>JmsActivationSpecFactory</interfacename>. The
            default is to autodetect the JMS provider and its
            <interfacename>ActivationSpec</interfacename> class (see
            <classname>DefaultJmsActivationSpecFactory</classname>)</para></entry>
          </row>

          <row>
            <entry>destination-resolver</entry>

            <entry><para>A reference to the
            <interfacename>DestinationResolver</interfacename> strategy for
            resolving JMS <interfacename>Destinations</interfacename>.
            </para></entry>
          </row>

          <row>
            <entry>message-converter</entry>

            <entry><para>A reference to the
            <interfacename>MessageConverter</interfacename> strategy for
            converting JMS Messages to listener method arguments. Default is a
            <classname>SimpleMessageConverter</classname>.</para></entry>
          </row>

          <row>
            <entry>destination-type</entry>

            <entry><para>The JMS destination type for this listener:
            <literal>queue</literal>, <literal>topic</literal> or
            <literal>durableTopic</literal>. The default is
            <literal>queue</literal>.</para></entry>
          </row>

          <row>
            <entry>client-id</entry>

            <entry><para>The JMS client id for this listener container. Needs
            to be specified when using durable subscriptions.</para></entry>
          </row>

          <row>
            <entry>acknowledge</entry>

            <entry><para>The native JMS acknowledge mode:
            <literal>auto</literal>, <literal>client</literal>,
            <literal>dups-ok</literal> or <literal>transacted</literal>. A
            value of <literal>transacted</literal> activates a locally
            transacted <interfacename>Session</interfacename>. As an
            alternative, specify the <literal>transaction-manager</literal>
            attribute described below. Default is
            <literal>auto</literal>.</para></entry>
          </row>

          <row>
            <entry>transaction-manager</entry>

            <entry><para>A reference to a Spring
            <classname>JtaTransactionManager</classname> or a
            <interfacename>javax.transaction.TransactionManager</interfacename>
            for kicking off an XA transaction for each incoming message. If
            not specified, native acknowledging will be used (see the
            "acknowledge" attribute).</para></entry>
          </row>

          <row>
            <entry>concurrency</entry>

            <entry><para>The number of concurrent sessions/consumers to start
            for each listener. Can either be a simple number indicating the
            maximum number (e.g. "5") or a range indicating the lower as well
            as the upper limit (e.g. "3-5"). Note that a specified minimum is
            just a hint and will typically be ignored at runtime when using a
            JCA listener container. Default is 1.</para></entry>
          </row>

          <row>
            <entry>prefetch</entry>

            <entry><para>The maximum number of messages to load into a single
            session. Note that raising this number might lead to starvation of
            concurrent consumers!</para></entry>
          </row>
        </tbody>
      </tgroup>
    </table>
  </section>
</chapter>
