topicsupplier.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.naming.*;
import javax.jms.*;
import java.util.*;
import java.io.*;

/**
 * Implements the functionality to publish a message to
 * a topic. Extends the TopicManager for init info.
 */
public class TopicSupplier extends TopicManager{

	private TopicPublisher topicPublisher;

	/** 
	 * Initializes the topic supplier.
	 */
	public TopicSupplier(Context context){

    // Call superclass TopicManager constructor
    super(context);

    try{
  		// Create topic publisher
  		System.out.println("Creating topic publisher...");
  		topicPublisher = topicSession.createPublisher(topic);
    }catch(JMSException e){
      System.out.println("Problem creating Topic Publisher");
      e.printStackTrace();
    }
	}


	/**
   * Publish an order message to a topic.
   */
	public void sendOrder(OrderItem message) throws JMSException {
		System.out.println("Publishing order message:" + message);

		// Create empty ObjectMessage on session
		System.out.println("Creating empty object message...");
		ObjectMessage sendingMessage = topicSession.createObjectMessage();
		
		// Start the topicconnection
		System.out.println("Starting topic connection...");
		topicConnection.start();
		
		// Set the order object onto the message carrier
		System.out.println("Setting order item into message...");
		sendingMessage.setObject((Serializable) message);
		
		// Send the message
		System.out.println("Publishing the order message...");
		topicPublisher.publish(sendingMessage);
	}
	
	/**
	  * Close JMS related objects.
	  */
	public void close() throws JMSException {
		topicPublisher.close();
		topicSession.close();
		topicConnection.close();
	}

  /**
   * Main method used to execute the TopicSupplier example
   */
	public static void main(String[] args) throws Exception {
		try {
			// Get some orders from the OrderManager class
			System.out.println("Getting a bunch of orders to send...");
			Collection orders = OrderManager.getOrders();

			// For each order, get order request and send to consumer
			Iterator it = orders.iterator();
			while (it.hasNext()) {
				// Get an OrderItem object to send
				OrderItem item = (OrderItem) it.next();

				// Create JNDI context
				Context context = Props.getInitialContext();

				// Create new TopicSupplier
				System.out.println("Creating new TopicSupplier...");
				TopicSupplier topicSupplier = new TopicSupplier(context);
               
        // Send the order
        System.out.println("Initiating order to send...");
        topicSupplier.sendOrder(item);
        
        // Close TopicSupplier
        System.out.println("Closing TopicSupplier...");
        topicSupplier.close();
      }
    }catch(Exception e){
      System.out.println("Problem executing topic supplier");
      e.printStackTrace();
    }      
	}
}