Java – Message Driven Bean with a Datasource

ejbjavajmsmessage-driven-bean

My question is how do I configure an EJB 3.0 style message driven bean to use a configured JMS datasource in jboss.

For example, my MDB looks something like:

@MessageDriven(mappedName = "ExampleMDB", activationConfig = {

        @ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Topic"),
        @ActivationConfigProperty(propertyName = "destination", propertyValue = "MyTopic"),
        @ActivationConfigProperty(propertyName = "channel", propertyValue = "MyChannel"),

})
@ResourceAdapter(value = "wmq.jmsra.rar")
@TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
@TransactionManagement(TransactionManagementType.BEAN)
public class MyMDB implements MessageListener {
 .....
}

But I would like the bean to attached to a given JMS datasource ( in the case of jboss 4.2.2 this is in deploy/jms/jms-ds.xml). Perhaps this is not even possible but is worth asking.

Best Answer

If I understood your problem correctly, MyMDB listens to a topic on WebLogic, and you want to use an additional JMS destination provided by JBoss, defined in a deployed configuration file and identified by its JNDI name (by default, deploy/jms/jms-ds.xml only contains the configuration for the JMS provider and connection factories -- no data sources).

The easiest way is to let the container inject the JMS destination and a connection factory via its JNDI name (in JBoss the JMS destinations are configured by deploying xxx-service.xml files). On startup you can then initialize the connection, and perform cleanup as soon as the MDB is released.

The following examples shows injection (@Resource) and resource managemend (@PostConstruct and @PreDestroy). The JMS connection and destination is used in useJmsDestination(String) to send a text message.

public class MyMDB implements MessageListener {

    @Resource(mappedName = "queue/YourQueueName") // can be topic too
    private Queue targetDestination;

    @Resource(mappedName = "QueueConnectionFactory") // or ConnectionFactory
    private QueueConnectionFactory factory;

    private Connection conn;

    public void onMessage(Message m) {
        // parse message and do what you need to do
        ...
        // do something with the message and the JBoss JMS destination
        useJmsDestination(messageString);     
    }

    private void useJmsDestination(String text) {
        Session session = null;
        MessageProducer producer = null;

        try {
            session = conn.createSession(true, Session.AUTO_ACKNOWLEDGE);
            producer = session.createProducer(targetDestination);
            TextMessage msg = session.createTextMessage(text);
            producer.send(msg);
        } catch (JMSException e) {
            throw new RuntimeException(e);
        } finally {
            try {
                if (producer != null) {
                    producer.close();
                }
                if (session != null) {
                    session.close();
                }
            } catch (JMSException e) {
                // handle error, should be non-fatal, as the message is already sent.
            }
        }
    }


    @PostConstruct
    void init() {
        initConnection();
        // other initialization logic
        ...
    }

    @PreDestroy
    void cleanUp() {
        closeConnection();
        // other cleanup logic
        ...
    }

    private void initConnection() {
        try {
            conn = factory.createConnection();
        } catch (JMSException e) {
            throw new RuntimeException("Could not initialize connection", e);
        }
    }

    private void closeConnection() {
        try {
            conn.close();
        } catch (JMSException e) {
            // handle error, should be non-fatal, as the connection is being closed
        }
    }
}

I hope this can help you.

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