JMS Synchronous Invocations : Quad Channel JMS-to-JMS

Introduction

The following diagram depicts quad-channel JMS synchronous invocations of the WSO2 Enterprise Integrator (WSO2 EI).

Prerequisites

Follow the steps below to set the prerequisites up before you start.

1. Download and set up Apache ActiveMQ. For instructions, see Installation Prerequisites. 
2. Copy the following client libraries from the <AMQ_HOME>/lib directory to the <EI_HOME>/lib directory.  
   ActiveMQ 5.8.0 and above   
   
   • • activemq-broker-5.8.0.jar
     • activemq-client-5.8.0.jar
     • geronimo-jms_1.1_spec-1.1.1.jar
     • geronimo-j2ee-management_1.1_spec-1.0.1.jar
     • hawtbuf-1.9.jar   

             Earlier versions of ActiveMQ

   • • activemq-core-5.5.1.jar
     • geronimo-j2ee-management_1.0_spec-1.0.jar
     • geronimo-jms_1.1_spec-1.1.1.jar

3. Add the following properties to the <EI_HOME>/conf/jndi.properties file. For more information, see Setting up WSO2 EI and ActiveMQ.

   queue.ClientReq = ClientReq
   queue.BEReq = BEReq
   queue.BERes = BERes

4. Uncomment the following sections in the <EI_HOME>/conf/axis2/axis2.xml file.

   1. To enable the JMS transport sender:

      <transportSender name="jms" class="org.apache.axis2.transport.jms.JMSSender"/>

   2. To enable the JMS transport listener:

      <!--Uncomment this and configure as appropriate for JMS transport support, after setting up your JMS environment (e.g. ActiveMQ)--><transportReceiver name="jms" class="org.apache.axis2.transport.jms.JMSListener">
             <parameter name="myTopicConnectionFactory" locked="false">
                 <parameter name="java.naming.factory.initial" locked="false">org.apache.activemq.jndi.ActiveMQInitialContextFactory</parameter>
                 <parameter name="java.naming.provider.url" locked="false">tcp://localhost:61616</parameter>
                 <parameter name="transport.jms.ConnectionFactoryJNDIName" locked="false">TopicConnectionFactory</parameter>
                  <parameter name="transport.jms.ConnectionFactoryType" locked="false">topic</parameter>
             </parameter>
        
             <parameter name="myQueueConnectionFactory" locked="false">
                 <parameter name="java.naming.factory.initial" locked="false">org.apache.activemq.jndi.ActiveMQInitialContextFactory</parameter>
                 <parameter name="java.naming.provider.url" locked="false">tcp://localhost:61616</parameter>
                 <parameter name="transport.jms.ConnectionFactoryJNDIName" locked="false">QueueConnectionFactory</parameter>
                  <parameter name="transport.jms.ConnectionFactoryType" locked="false">queue</parameter>
             </parameter>
        
             <parameter name="default" locked="false">
                 <parameter name="java.naming.factory.initial" locked="false">org.apache.activemq.jndi.ActiveMQInitialContextFactory</parameter>
                 <parameter name="java.naming.provider.url" locked="false">tcp://localhost:61616</parameter>
                 <parameter name="transport.jms.ConnectionFactoryJNDIName" locked="false">QueueConnectionFactory</parameter>
                  <parameter name="transport.jms.ConnectionFactoryType" locked="false">queue</parameter>
             </parameter>
         </transportReceiver>

Sample configuration

Following is a sample configuration of WSO2 EI for quad-channel  JMS synchronous invocations.

<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 of the above 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 WSO2 EI proxy to pick messages from ClientReq queue, and send to BEReq queue .
   
3. The back-end picks messages from the BEReq queue, processes and places response messages to BERes queue.
   
4. Once a response is available in BERes queue, the proxy service picks it and sends back to ClientRes queue.
   
5. The client picks it as the response message.