/*

  * Copyright (C) The Apache Software Foundation. All rights reserved.

  *

  * This software is published under the terms of the Apache Software License

  * version 1.1, a copy of which has been included with this distribution in

  * the LICENSE file.

  * 

  * $Id: Consumer.java 155459 2005-02-26 13:24:44Z dirkv $

  */

 package org.apache.commons.messenger.tool;

 import java.io.FileWriter;

 import java.io.OutputStreamWriter;

 import java.io.PrintWriter;

 import java.io.Writer;

 import javax.jms.Destination;

 import javax.jms.JMSException;

 import javax.jms.Message;

 import javax.jms.TextMessage;

 import org.apache.commons.messenger.Messenger;

 import org.apache.commons.messenger.MessengerManager;

 /** <p><code>Consumer</code> is a sample program that 

   * consumes a single message and either writes it to 

   * either stanard output or a named file.</p>

   *

   * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>

   * @version $Revision: 155459 $

   */

 public class Consumer {

     private Messenger messenger;

     public static void main(String[] args) {

         try {

             Consumer client = new Consumer();

             client.run( args );

         }

         catch (JMSException e) {

             System.out.println( "Caught: " + e );

             Exception linked = e.getLinkedException();

             if ( linked != null ) {

                 System.out.println( "Underlying exception: " + linked );

                 linked.printStackTrace();

             }

             else {

                 e.printStackTrace();

             }

         }

         catch (Exception e) {

             System.out.println( "Caught: " + e );

             e.printStackTrace();

         }

     }

     public void run(String[] args) throws Exception {

         if ( args.length < 2 ) {

             System.out.println( "Usage: Consumer messengerName destination [fileName]" );

             System.out.println( "If no fileName is provided then the current input stream is used" );

             return;

         }

         String name = args[0];

         String subject = args[1];

         messenger = MessengerManager.get( name );

         if ( messenger == null ) {

             throw new JMSException( "No such messenger called: " + name );

         }

         Destination destination = messenger.getDestination( subject );

         if ( destination == null ) {

             throw new JMSException( "Could not find destination: " + subject );

         }

         Writer writer = ( args.length > 2 ) 

             ? new FileWriter( args[2] )

             : new OutputStreamWriter( System.out );

         Message message = messenger.receive( destination );

         writeMessage( message, writer );

         // close the JMS connection to release any background threads        

         messenger.close();

     }    

     /** Writes the given message to the Writer */

     protected void writeMessage(Message message, Writer out) throws Exception {

         PrintWriter writer = new PrintWriter(out);

         if ( message instanceof TextMessage ) {

             TextMessage textMessage = (TextMessage) message;

             writer.println( textMessage.getText() );

         }

         writer.close();

     }

 }