[jboss-user] [Messaging, JMS & JBossMQ] - Re: MDB multiple queues

[jpersson]

Thanks! 

Now my MDB is partly annotated and partly XML-descriptor driven. Works fine.

When my MDB runs in two instances is there a concurrency issue when passing incoming messages to the 'next' queue (two mdb instances sending/routing to a single queue) ?

THIS IS SOURCE MDB:
package com.mdm.mdb.bean;

import javax.annotation.Resource;
import javax.ejb.MessageDriven;
import javax.ejb.ActivationConfigProperty;
import javax.jms.Message;
import javax.jms.TextMessage;
import javax.jms.MapMessage;
import javax.jms.ObjectMessage;
import javax.jms.MessageListener;
import javax.jms.JMSException;
import javax.jms.Queue;
import javax.jms.QueueConnection;
import javax.jms.QueueConnectionFactory;
import javax.jms.QueueSender;
import javax.jms.QueueSession;
import javax.jms.Session;
import com.thoughtworks.xstream.XStream;
import static java.lang.System.out;

/** Message Listener setup with annotations, override with XML-descriptor. */
@MessageDriven(activationConfig ={@ActivationConfigProperty(propertyName="destinationType",
	 propertyValue="javax.jms.Queue")})
public class ServiceBrixRoutingMDB implements MessageListener{

	// Dependecy injection.
   	@Resource(mappedName="java:ConnectionFactory")
   	QueueConnectionFactory connectionFactory;

	// Dependecy injection.
   	QueueConnection queueConnection;

	// Dependecy injection.
   	@Resource(mappedName="queue/mdm-input")
   	Queue mDMInputQueue;

	// Parser for Object to XML marshaller.
   	private XStream xstream = null;

	/** This is the entry for the message listener. */
   	public void onMessage(Message messageFromServicemix){
    	try{
     		if(messageFromServicemix instanceof TextMessage){
				sendMesageToMDM();
			}
		}catch(Exception e){
			out.println(e);
		}
   	}

	/** Send MapMessage to MDM node. */
   	private void sendMesageToMDM() throws JMSException{
	   	QueueSender qsender = null;
	   	queueConnection = getConnection();
		QueueSession qsession = queueConnection.createQueueSession(
							false, Session.AUTO_ACKNOWLEDGE);
		TextMessage mdmMessagge = null;
		qsender = qsession.createSender(mDMInputQueue);
		mdmMessagge = qsession.createTextMessage("MESSAGE_FROM_SERVICEMIX");
		qsender.send(mdmMessagge);
		qsession.close();
		queueConnection.close();
		queueConnection = null;
   	}

	/** Get QueConnection from JBoss Factory. */
   	private QueueConnection getConnection() throws JMSException{
      if (queueConnection == null){
         synchronized(connectionFactory){
            if(queueConnection == null){
               queueConnection = connectionFactory.createQueueConnection();
            }
         }
      }

      return queueConnection;
   	}

	/** Get thread safe XStream object for marshall/unmarshall Object/XML. */
   	private XStream getXStream(){
		if(xstream == null){xstream = new XStream();}return xstream;
   	}
}

THIS IS SOURCE EJBJAR-XML:
<?xml version="1.0" encoding="UTF-8"?>
<ejb-jar
        xmlns="http://java.sun.com/xml/ns/javaee"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                            http://java.sun.com/xml/ns/javaee/ejb-jar_3_0.xsd"
        version="3.0">
   Message Driven Bean for Routing from Servicemix to Flowbrix
   <display-name>MDB for routing from Servicemix to Flowbrix</display-name>
   <enterprise-beans>
   
      <message-driven>
	   <ejb-name>CPAssistedRequestMDB</ejb-name>
	   <ejb-class>com.smarttrust.mdm.mdb.bean.ServiceBrixRoutingMDB</ejb-class>
         <transaction-type>Bean</transaction-type>
         <message-destination-type>javax.jms.Queue</message-destination-type>
       <activation-config>   
          <activation-config-property>
          	<activation-config-property-name>acknowledgeMode</activation-config-property-name>
          	<activation-config-property-value>AUTO_ACKNOWLEDGE</activation-config-property-value>
          </activation-config-property>
        </activation-config>
      </message-driven>
      
      <message-driven>
	   <ejb-name>CPAssistedReplyMDB</ejb-name>
	   <ejb-class>com.smarttrust.mdm.mdb.bean.ServiceBrixRoutingMDB</ejb-class>
         <transaction-type>Bean</transaction-type>
         <message-destination-type>javax.jms.Queue</message-destination-type>
       <activation-config>   
          <activation-config-property>
          	<activation-config-property-name>acknowledgeMode</activation-config-property-name>
          	<activation-config-property-value>AUTO_ACKNOWLEDGE</activation-config-property-value>
          </activation-config-property>
        </activation-config>
      </message-driven>      
      
   </enterprise-beans>
</ejb-jar>




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