3.2 JMS Adapters

3.2 JMS Adapters
Prev	3. Adapters	Next

Spring Integration provides two adapters for accepting JMS messages (as mentioned above): JmsSource and JmsGateway. The former uses Spring's JmsTemplate to receive based on a polling period. The latter configures and delegates to an instance of Spring's DefaultMessageListenerContainer.

The JmsSource 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 JmsSource can then be referenced from a "channel-adapter" element that connects the source to a MessageChannel instance. The following example defines a JMS source with a JmsTemplate as a constructor-argument.

<bean id="jmsSource" class="org.springframework.integration.adapter.jms.JmsSource">
    <constructor-arg ref="jmsTemplate"/>
</bean>

In most cases, Spring Integration's message-driven JmsGateway is more appropriate since it delegates to a MessageListener container, supports dynamically adjusting concurrent consumers, and can also handle replies. The JmsGateway requires references to a ConnectionFactory, and a Destination (or 'destinationName'). The following example defines a JmsGateway that receives from the JMS queue called "exampleQueue". Note that the 'expectReply' property has been set to 'true' (it is 'false' by default):

<bean class="org.springframework.integration.adapter.jms.JmsGateway">
    <property name="connectionFactory" ref="connectionFactory"/>
    <property name="destinationName" value="exampleQueue"/>
    <property name="expectReply" value="true"/>
</bean>

The JmsTarget implements the MessageTarget interface and is capable of mapping 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). In Section 4.2.4, “Configuring Adapters”, you will see how to configure a JMS target adapter with Spring Integration's namespace support.