votelistener.java

高级java2 大学教程(含源码,经典的Java学习教程

// VoteListener.java
// VoteListener is the message listener for the
// receiver of the "Votes" queue. It implements 
// the specified onMessage method to update the 
// GUI with the received vote.
package com.deitel.advjhtp1.jms.voter;

// Java extension packages
import javax.jms.*;

public class VoteListener implements MessageListener {

   private VoteCollector voteCollector;

   // VoteListener constructor
   public VoteListener( VoteCollector collector )
   {
      voteCollector = collector;
   }

   // receive new message
   public void onMessage( Message message )
   {
      TextMessage voteMessage;

      // retrieve and process message
      try {

         if ( message instanceof TextMessage ) {
            voteMessage = ( TextMessage ) message;
            String vote = voteMessage.getText();
            voteCollector.addVote( vote );

            System.out.println( "Received vote: " + vote );
         }

         else {
            System.out.println( "Expecting " +
               "TextMessage object, received " +
               message.getClass().getName() );
         }
      }

      // process JMS exception from message
      catch ( JMSException jmsException ) {
         jmsException.printStackTrace();
      }

   } // end method onMessage
}

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