/*

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

  */

 package org.apache.commons.messenger;

 import java.net.URL;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServlet;

 /** <p><code>InitMessengerServlet</code> is a simple servlet that

  * will initialize the MessengerManager from a URL specified in the

  * web.xml deployment descriptor.</p>

  *

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

  * @version $Revision: 155459 $

  */

 public class InitMessengerServlet extends HttpServlet {

     private static boolean initialized = false;

     public InitMessengerServlet() {

     }

     public void init() throws ServletException {

         if ( ! initialized ) {

             initialized = true;

             getServletContext().log( "About to initialize MessengerManager" );

             String config = getRequiredInitParmeter( "config", "The URL of the Messenger XML deployment document" );

             try {            

                 URL url = getServletContext().getResource( config );

                 MessengerManager.configure( url.toString() );

             }

             catch (Exception e) {

                 throw new ServletException( "Failed to initialise MessengerManager from config: " + config + ". Reason : " + e, e );

             }

         }

     }

     // Implementation methods

     //-------------------------------------------------------------------------        

     protected String getRequiredInitParmeter(String key, String description) throws ServletException {

         String value = getInitParameter( key );

         if ( value == null || value.length() == 0 ) {

             throw new ServletException( 

                 "No initialization parameter for parameter: " + key 

                 + " description: " + description 

             );

         }

         return value;

     }

 }