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JMS Synchronous Invocations: Quad Channel JMS-to-JMS

The example demonstrates how WSO2 Micro Integrator handles quad-channel JMS synchronous invocations.

Synapse configuration

Given below is the synapse configuration of the proxy service that mediates the above use case. Note that you need to update the JMS connection URL according to your broker as explained below.

See the instructions on how to build and run this example.

<proxy name="QuadJMS" transports="jms" xmlns="http://ws.apache.org/ns/synapse">
          <target>
              <inSequence>
                  <property action="set" name="transport.jms.ContentTypeProperty" value="Content-Type" scope="axis2"/>
                  <log level="full" xmlns="http://ws.apache.org/ns/synapse"/>
                  <send>
                      <endpoint>
                          <address uri="jms:/BEReq?transport.jms.ConnectionFactoryJNDIName=QueueConnectionFactory&amp;java.naming.factory.initial=org.apache.activemq.jndi.ActiveMQInitialContextFactory&amp;java.naming.provider.url=tcp://localhost:61616&amp;transport.jms.DestinationType=queue&amp;transport.jms.ReplyDestination=BERes"/>
                      </endpoint>
                  </send>
              </inSequence>
              <outSequence>
                  <send/>
              </outSequence>
          </target>
          <parameter name="transport.jms.ContentType">
              <rules>
                  <jmsProperty>contentType</jmsProperty>
                  <default>text/xml</default>
              </rules>
          </parameter>
          <parameter name="transport.jms.Destination">ClientReq</parameter>
</proxy>

The message flow handled by the sample configuration is as follows:

  1. The JMSReplyTo property of the JMS message is set to ClientRes . Therefore, the client sends a JMS message to the ClientReq queue.
  2. The transport.jms.ReplyDestination value is set to BERes. This enables the Micro Integrator proxy to pick messages from the ClientReq queue and send to the BEReq queue.
  3. The back-end picks messages from the BEReq queue, processes and places response messages to the BERes queue.
  4. Once a response is available in BERes queue, the proxy service picks the response message, and sends it back to the ClientRes queue.
  5. The client the message as the response message.

The Synapse artifacts used are explained below.

Artifact Type Description
Proxy Service A proxy service is used to receive messages and to define the message flow.
Property Mediator The JMS transport uses the transport.jms.ContentTypeProperty property in the above configuration to determine the content type of the response message. If this property is not set, the JMS transport treats the incoming message as plain text.
Send Mediator 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 as shown in the exampe. Values of connection factory parameters depend on the type of JMS broker.

  • If you have already specified the endpoint's connection factory parameters (for the JMS sender configuration) in the deployment.toml file, 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 deployment.toml file:

    When the broker is ActiveMQ
    jms:/BEReq?transport.jms.ConnectionFactory=QueueConnectionFactory

    When the broker is WSO2 Message Broker
    jms:/BEReq?transport.jms.ConnectionFactory=QueueConnectionFactory

Note

Be sure to replace the ' & ' character in the endpoint URL with '&amp;' 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}

Build and run

Create the artifacts:

  1. Set up WSO2 Integration Studio.
  2. Create an integration project with an ESB Configs module and an Composite Exporter.
  3. Create the proxy service with the configurations given above.
  4. Deploy the artifacts in your Micro Integrator.

Set up the broker:

  1. Configure a broker with your Micro Integrator instance. Let's use Active MQ for this example.
  2. Start the broker.
  3. Start the Micro Integrator (after starting the broker).

Set up the back-end service:

  1. Download the back-end service.
  2. Extract the downloaded zip file.
  3. Open a terminal, navigate to the axis2Server/bin/ directory inside the extracted folder.
  4. Execute the following command to start the axis2server with the SimpleStockQuote back-end service:

    sh axis2server.sh
    axis2server.bat

Invoke the proxy service by send a simple message.

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