Message Driven Bean

Message Driven Bean

Message Driven Bean (MDB) is an enterprise bean which runs inside the EJB container and it acts as Listener for the JMS asynchronous message . It does not have Home and Remote interface as Session or Entity bean. It is called by container when container receives JMS asynchronous message. MDB has to implement MessageListener which has a method onMessage(Message msg). When the container calls the MDB it passes the message to onMesage() method and then MDB process that message.

Example Program:

Server Side Program

package org.jboss.tutorial.mdb.bean;

import javax.ejb.ActivationConfigProperty;
import javax.ejb.MessageDriven;
import javax.jms.BytesMessage;
import javax.jms.Message;
import javax.jms.MessageListener;

@MessageDriven(activationConfig = {
@ActivationConfigProperty(propertyName="destinationType", propertyValue="javax.jms.Queue"),
@ActivationConfigProperty(propertyName="destination", propertyValue="queue/tutorial/example")
})
public class ExampleMDB implements MessageListener {
public void onMessage(Message recvMsg) {
System.out.println("----------------");
System.out.println("Received message");
System.out.println("----------------");
System.out.println("Received message object: " + recvMsg);
BytesMessage byteMsg = (BytesMessage) recvMsg;
}
}

Client Side Program
package org.jboss.tutorial.mdb.client;


import java.io.FileInputStream;
import java.util.Properties;

import javax.jms.Queue;
import javax.jms.QueueConnection;
import javax.jms.QueueConnectionFactory;
import javax.jms.QueueSender;
import javax.jms.QueueSession;
import javax.jms.TextMessage;
import javax.naming.InitialContext;

public class Client {
public static void main(String[] args) throws Exception {
QueueConnection cnn = null;
QueueSender sender = null;
QueueSession session = null;

Properties props = new Properties();
props.load(new FileInputStream("EJBJNDI.prop")); //
InitialContext ic = new InitialContext(props);

//InitialContext ctx = new InitialContext();
Queue queue = (Queue) ic.lookup("queue/tutorial/example");
QueueConnectionFactory factory = (QueueConnectionFactory) ic.lookup("ConnectionFactory");
cnn = factory.createQueueConnection();
session = cnn.createQueueSession(false, QueueSession.AUTO_ACKNOWLEDGE);

TextMessage msg = session.createTextMessage("Hello World");

sender = session.createSender(queue);
sender.send(msg);
System.out.println("Message sent successfully to remote queue.");

}
}

EJBJNDI.prop
java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory
java.naming.factory.url.pkgs=org.jboss.naming:org.jnp.interfaces
java.naming.provider.url=localhost:1099