// ========================================================================
   // Copyright (c) 2006-2009 Mort Bay Consulting Pty. Ltd.
   // ------------------------------------------------------------------------
   // All rights reserved. This program and the accompanying materials
   // are made available under the terms of the Eclipse Public License v1.0
   // and Apache License v2.0 which accompanies this distribution.
   // The Eclipse Public License is available at 
   // http://www.eclipse.org/legal/epl-v10.html
   // The Apache License v2.0 is available at
  // http://www.opensource.org/licenses/apache2.0.php
  // You may elect to redistribute this code under either of these licenses. 
  // ========================================================================
  
  package org.eclipse.jetty.annotations;
  
  import javax.servlet.ServletContextAttributeListener;
  import javax.servlet.ServletContextListener;
  import javax.servlet.ServletRequestAttributeListener;
  import javax.servlet.ServletRequestListener;
  import javax.servlet.http.HttpSessionAttributeListener;
  import javax.servlet.http.HttpSessionListener;
  
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.eclipse.jetty.webapp.DiscoveredAnnotation;
  import org.eclipse.jetty.webapp.MetaData;
  import org.eclipse.jetty.webapp.WebAppContext;
  import org.eclipse.jetty.webapp.Origin;
  
  /**
   * WebListenerAnnotation
   *
   *
   */
  public class WebListenerAnnotation extends DiscoveredAnnotation
  {
      private static final Logger LOG = Log.getLogger(WebListenerAnnotation.class);
  
      /**
       * @param context
       * @param className
       */
      public WebListenerAnnotation(WebAppContext context, String className)
      {
          super(context, className);
      }
  
      /** 
       * @see org.eclipse.jetty.annotations.ClassAnnotation#apply()
       */
      public void apply()
      {
          // TODO check algorithm against ordering rules for descriptors v annotations
          
          Class clazz = getTargetClass();
          
          if (clazz == null)
          {
              LOG.warn(_className+" cannot be loaded");
              return;
          }
  
          try
          {
              if (ServletContextListener.class.isAssignableFrom(clazz) || 
                      ServletContextAttributeListener.class.isAssignableFrom(clazz) ||
                      ServletRequestListener.class.isAssignableFrom(clazz) ||
                      ServletRequestAttributeListener.class.isAssignableFrom(clazz) ||
                      HttpSessionListener.class.isAssignableFrom(clazz) ||
                      HttpSessionAttributeListener.class.isAssignableFrom(clazz))
              {
                  java.util.EventListener listener = (java.util.EventListener)clazz.newInstance();
                  MetaData metaData = _context.getMetaData();
                  if (metaData.getOrigin(clazz.getName()+".listener") == Origin.NotSet)
                      _context.addEventListener(listener);
              }
              else
                  LOG.warn(clazz.getName()+" does not implement one of the servlet listener interfaces");
          }
          catch (Exception e)
          {
              LOG.warn(e);
          }
      }
  }