/*
* Message driven beans in JBoss use the Java Messaging Servive. (JMS)
*/
package com.myjsm;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.jms.TopicConnectionFactory;
import javax.jms.TopicConnection;
import javax.jms.TopicSession;
import javax.jms.TopicSubscriber;
import javax.jms.Topic;
import javax.jms.Message;
import javax.jms.TextMessage;
import javax.jms.Session;
import javax.jms.MessageListener;
import javax.jms.JMSException;
/**
* This class Implements a message subscriber, It can be used to recieve notification
* messages in a many to many scenario to the topic specified by the topicJNDI member variable.
*/
public class JmsSubscriber implements MessageListener {
final String topicJNDI = "topic/testTopic";
// Topic connection, hold on to this so you may close it.
TopicConnection topicConnection;
// Topic session, hold on to this so you may close it. Also used to create messages.
TopicSession topicSession;
// Subsrciber
TopicSubscriber topicSubscriber;
// Destination to subscribe to
Topic topic;
/**
* Use close() when finished with object.
*
* @param factoryJNDI name of the topic connection factory to look up.
* @param topicJNDI name of the topic destination to look up
*/
public JmsSubscriber() throws JMSException, NamingException {
// Get the initial context
Context jndicontext = getInitialContext();
// Get the connection factory
TopicConnectionFactory topicFactory =
(TopicConnectionFactory)jndicontext.lookup( "ConnectionFactory");
// Create the connection
topicConnection = topicFactory.createTopicConnection();
// Create the session with: No transaction and auto ack
topicSession = topicConnection.createTopicSession(false, Session.AUTO_ACKNOWLEDGE);
// Look up the destination
topic = (Topic)jndicontext.lookup(topicJNDI);
// Create a subsriber
topicSubscriber = topicSession.createSubscriber(topic);
// Set the message listener, which is this class since we implement
// the MessageListener interface
topicSubscriber.setMessageListener(this);
System.out.println("HelloSubscriber subscribed to topic: " + topicJNDI);
// For the message listener to receive any messages the connection must be started
topicConnection.start();
}
/**
* Implementation of the MessageListener interface, messages will be received through this method.
*/
public void onMessage(Message m) {
// Unpack the message, be carefull when casting to correct message type
// onMessage should not through any application exceptions.
try {
String msg = ((TextMessage)m).getText();
System.out.println("HelloSubscriber got message: " + msg);
} catch(JMSException ex) {
System.err.println("Could not get text message: " + ex);
ex.printStackTrace();
}
}
/**
* Close session and connection.
*/
public void close() throws JMSException {
topicSession.close();
topicConnection.close();
}
/**
* Run an example subscribing to topic testTopic. Only works up to and including JBoss 2.4.x
*/
public static void main(String[] args) {
try {
// Create a HelloSubsriber
JmsSubscriber subscriber = new JmsSubscriber();
} catch(Exception ex) {
System.err.println("An exception occured while testing HelloPublisher: " + ex);
ex.printStackTrace();
}
}
public static javax.naming.Context getInitialContext() throws javax.naming.NamingException {
//return new InitialContext(); /*** context initialized by jndi.properties file
java.util.Properties p = new java.util.Properties();
p.put(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");
p.put(Context.URL_PKG_PREFIXES, "jboss.naming:org.jnp.interfaces");
p.put(Context.PROVIDER_URL, "localhost");
return new InitialContext(p);
}
}