Using the ESB as JMS Consumer and Producer

This section describes how to configure the ESB Profile of WSO2 Enterprise Integrator (WSO2 EI) to work as a JMS-to-JMS proxy service.

Follow the steps below to configure the ESB Profile of WSO2 EI to listen to a JMS queue and consume messages, and then send those messages to another JMS queue.

1. Configure the ESB Profile of WSO2 EI with Apache ActiveMQ and set up the JMS listener and sender. For instructions, see Configure with ActiveMQ.
   

2. Create a proxy service with the following configuration. To create a proxy service using Tooling, see Working with Proxy Services via Tooling.

   <proxy name="StockQuoteProxy" transports="jms">
      <target>
          <inSequence>
              <property action="set" name="OUT_ONLY" value="true"/>
              <send>
                  <endpoint>
                     <address uri=""/> <!-- Specify the JMS connection URL here -->
                  </endpoint>
              </send>
          </inSequence>
      </target>
   </proxy>

   Proxy service configuration

   In the sample configuration above, the 'transports' property is set to 'jms', which allows the ESB to receive JMS messages. This proxy service listens to a JMS queue named StockQuoteProxy and sends messages to another queue named SimpleStockQuoteService. The OUT_ONLY property is set to true, which indicates that the message exchange is one-way. To send a message to a JMS queue, you should define the JMS connection URL as the endpoint address (which should be invoked via the Send mediator). There are two ways to specify the endpoint URL

   • Specify the JNDI name of the JMS queue and the connection factory parameters in the JMS connection URL in the exampe below. Values of connection factory parameters depend on the type of the JMS broker.

     When the broker is ActiveMQ

     jms:/SimpleStockQuoteService?transport.jms.ConnectionFactoryJNDIName=QueueConnectionFactory&java.naming.factory.initial=org.apache.activemq.jndi.ActiveMQInitialContextFactory&java.naming.provider.url=tcp://localhost:61616&transport.jms.DestinationType=queue

     When the broker is WSO2 Message Broker

     jms:/StockQuotesQueue?transport.jms.ConnectionFactoryJNDIName=QueueConnectionFactory&java.naming.factory.initial=org.wso2.andes.jndi.PropertiesFileInitialContextFactory&java.naming.provider.url=conf/jndi.properties&transport.jms.DestinationType=queue

     
     

   • If you have already specified the endpoint's connection factory parameters (for the JMS sender configuration) in the axis2.xml file (stored in the <EI_HOME>/conf/axis2/ directory), the connection URL in the proxy service should be as shown below. In this example, the endpoint URL of the proxy service refers the relevant connection factory in the axis2.xml file:

     When the broker is ActiveMQ

     jms:transport.jms.ConnectionFactory=QueueConnectionFactory

     When the broker is WSO2 Message Broker

     jms:/StockQuotesQueue?transport.jms.ConnectionFactory=QueueConnectionFactory

   Be sure to replace the '&' character in the endpoint URL with '&' to avoid the following exception:

   com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character '=' (code 61); expected a semi-colon after the reference for entity 'java.naming.factory.initial' at [row,col {unknown-source}

3. To place a message into a JMS queue, execute following command from the <EI_HOME>/samples/axis2Client directory.

ant stockquote -Dmode=placeorder -Dtrpurl="jms:/StockQuoteProxy?transport.jms.ConnectionFactoryJNDIName=QueueConnectionFactory&java.naming.factory.initial=org.apache.activemq.jndi.ActiveMQInitialContextFactory&java.naming.provider.url=tcp://localhost:61616&transport.jms.ContentTypeProperty=Content-Type&transport.jms.DestinationType=queue"

Generally, JMS is used for one-way, asynchronous message exchange. However you can perform synchronous messaging also with JMS. For more information, see JMS Synchronous Invocations : Dual Channel HTTP-to-JMS and JMS Synchronous Invocations : Quad Channel JMS-to-JMS.