Message-Driven Bean

Objectives

The objective is to learn how to develop a Message-Driven Bean (MDB).

MDB Life-cycle

Creation the jBoss PTP queue

Edit the file jbossmq-destinations-service.xml in $JBOSS/server/default/deploy/jms/ and add the following code:


<mbean code="org.jboss.mq.server.jmx.Queue"
       name="jboss.mq.destination:service=Queue,name=JyperionLogQueue">
  <depends optional-attribute-name="DestinationManager">jboss.mq:service=DestinationManager</depends>
</mbean>

Save. That's all. jBoss will create the queue..

MDB: The code

A MDB is a simple Java class implementant les interfaces MessageDrivenBean, MessageListener.
The most important method is public void onMessage(Message message). This method will be called by the container upon reception of a message.

MDB XDoclet tags

There are two tags to specify: @ejb.bean and the propriatary tag @jboss:destination-jndi-name:


/**
 * LogMBean
 * 
 * @ejb.bean
 *   name="LogMBean"
 *   acknowledge-mode="Auto-acknowledge"
 *   destination-type="javax.jms.Queue"
 *   subscription-durability="NonDurable"
 *   transaction-type="Container"
 * 
 * @jboss:destination-jndi-name name="queue/JyperionLogQueue"
 * 
 * @author janaudy
 */
public class LogMBean implements MessageDrivenBean, MessageListener { ...

... and that's all!

UML View

Exercise

Instead of using a PTP queue, you will develop a Pub/Sub application, like a Trading System, where a Trader registers an interest in a specific Topic.
You will have to configure jBoss to create a Pub/Sub Topic.