topicconsumer.java

BEA WebLogic Server 8.1大全 = BEA webLogic server 8.1 unleashed (美) Mark Artiges等著 袁毅 ... [等] 译 eng

package com.wls8unleashed.jms;

import javax.jms.*;
import javax.naming.*;

/** 
 * Implements a basic subscriber to a JMS topic.
 * Extends the TopicManager for some basic initialization
 * help.
 */
public class TopicConsumer extends TopicManager
	implements MessageListener {

	private TopicSubscriber topicSubscriber;
	public boolean quitFromReceiving = false;

	/**
	 * Constructor creates all of the objects to receive messages
	 */
	public TopicConsumer(Context context)
		throws NamingException, JMSException {
			
		// Call superclass constructor
		super(context);

		// Create subscriber
		System.out.println("Creating topic subscriber...");
		topicSubscriber = topicSession.createSubscriber(topic);
		
		// Register subscriber as a MessageListener
		System.out.println("Setting message listener...");
		topicSubscriber.setMessageListener(this);
		
		// Start the connection thread
		System.out.println("Starting connection thread...");
		topicConnection.start();
	}

	/**
	 * Implements the message listener and prints a message.
	 */
	public void onMessage(Message message) {
		MessageHandler handler = new MessageHandler();
		handler.onMessage(message);
	}

	/**
   * Close JMS related objects.
   */
	public void close() throws JMSException {
		topicSubscriber.close();
		this.topicSession.close();
		this.topicConnection.close();
	}

  /**
   * Main method used to execute the TopicConsumer example
   */
	public static void main(String[] args){
		try {
  		// Create JNDI context
  		Context context = Props.getInitialContext();

      // Create new TopicConsumer
      System.out.println("Creating new TopicConsumer...");
			TopicConsumer topicConsumer = new TopicConsumer(context);

			System.out.println(" TopicConsumer is ready to receive messages.");

  		// Receive messages until user quits from program or quit flags true.
			synchronized (topicConsumer) {
				while (!topicConsumer.quitFromReceiving) {
					try {
            // Wait for messages
						topicConsumer.wait();
					} catch (InterruptedException interruptedException) {
  					System.out.println("Interruption!");
  					interruptedException.printStackTrace();
					}
				}
			}

      // Close up resources when done and exit
			topicConsumer.close();
			context.close();
			System.exit(0);
    }catch(Exception e){
      System.out.println("Problem executing topic consumer");
      e.printStackTrace();
		}
	}
}