DurableSubscriptionExample.java

/*
 * Copyright 2009 Red Hat, Inc.
 * Red Hat licenses this file to you under the Apache License, version
 * 2.0 (the "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *    http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied.  See the License for the specific language governing
 * permissions and limitations under the License.
 */
package org.hornetq.jms.example;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.MessageProducer;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.Topic;
import javax.jms.TopicSubscriber;
import javax.naming.InitialContext;

import org.hornetq.common.example.HornetQExample;

/**
 * A simple JMS example that shows how to use a durable subscription.
 *
 * @author <a href="hgao@redhat.com">Howard Gao</a>
 */
public class DurableSubscriptionExample extends HornetQExample
{
   public static void main(final String[] args)
   {
      new DurableSubscriptionExample().run(args);
   }

   @Override
   public boolean runExample() throws Exception
   {
      Connection connection = null;
      InitialContext initialContext = null;
      try
      {
         // Step 1. Create an initial context to perform the JNDI lookup.
         initialContext = getContext(0);

         // Step 2. Look-up the JMS topic
         Topic topic = (Topic)initialContext.lookup("/topic/exampleTopic");

         // Step 3. Look-up the JMS connection factory
         ConnectionFactory cf = (ConnectionFactory)initialContext.lookup("/ConnectionFactory");

         // Step 4. Create a JMS connection
         connection = cf.createConnection();

         // Step 5. Set the client-id on the connection
         connection.setClientID("durable-client");

         // Step 6. Start the connection
         connection.start();

         // Step 7. Create a JMS session
         Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);

         // Step 8. Create a JMS message producer
         MessageProducer messageProducer = session.createProducer(topic);

         // Step 9. Create the subscription and the subscriber.
         TopicSubscriber subscriber = session.createDurableSubscriber(topic, "subscriber-1");

         // Step 10. Create a text message
         TextMessage message1 = session.createTextMessage("This is a text message 1");

         // Step 11. Send the text message to the topic
         messageProducer.send(message1);

         System.out.println("Sent message: " + message1.getText());

         // Step 12. Consume the message from the durable subscription

         TextMessage messageReceived = (TextMessage)subscriber.receive();

         System.out.println("Received message: " + messageReceived.getText());

         // Step 13. Create and send another message

         TextMessage message2 = session.createTextMessage("This is a text message 2");

         messageProducer.send(message2);

         System.out.println("Sent message: " + message2.getText());

         // Step 14. Close the subscriber - the server could even be stopped at this point!
         subscriber.close();

         // Step 15. Create a new subscriber on the *same* durable subscription.

         subscriber = session.createDurableSubscriber(topic, "subscriber-1");

         // Step 16. Consume the message

         messageReceived = (TextMessage)subscriber.receive();

         System.out.println("Received message: " + messageReceived.getText());

         // Step 17. Close the subscriber
         subscriber.close();

         // Step 18. Delete the durable subscription
         session.unsubscribe("subscriber-1");

         return true;
      }
      finally
      {
         if (connection != null)
         {
            // Step 19. Be sure to close our JMS resources!
            connection.close();
         }
         if (initialContext != null)
         {
            // Step 20. Also close the initialContext!
            initialContext.close();
         }
      }
   }
}