/*
    * Copyright 2000-2001,2004 The Apache Software Foundation.
    * 
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    * 
    *      http://www.apache.org/licenses/LICENSE-2.0
    * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  /*
   * PortletActionEvent.java
   *
   * Created on January 29, 2003, 4:20 PM
   */
  package org.apache.jetspeed.modules.actions.portlets;
  
  import java.lang.reflect.Method;
  
  import java.util.Enumeration;
  import java.util.HashMap;
  
  import org.apache.jetspeed.portal.Portlet;
  import org.apache.jetspeed.portal.portlets.GenericMVCPortlet;
  import org.apache.jetspeed.util.PortletSessionState;
  import org.apache.turbine.modules.ActionEvent;
  import org.apache.turbine.services.velocity.TurbineVelocity;
  import org.apache.turbine.util.ParameterParser;
  import org.apache.turbine.util.RunData;
  
  import org.apache.velocity.context.Context;
  
  
  /***
   * Provides form based action handling via the eventSubmit_do[action] pattern.
   * Works just like the mechanism described for the velocity portlet.  Extends
   * this convienent functionality to all GenericMVCPortlets
   * 
   * @author  tkuebler
   * @author <a href="mailto:weaver@apache.org">Scott T. Weaver</a>
   * @version $Id: PortletActionEvent.java,v 1.3.2.1 2003/02/24 18:45:42 tkuebler Exp $
   * @stereotype moment-interval
   */
  public abstract class PortletActionEvent
      extends ActionEvent
    {
    	
    	/***
    	 * Cache ActionEvent methods to avoid repeated replection
    	 * method lookups.
    	 */
    	private static final HashMap eventMethods = new HashMap();
  
      /***
       * You need to implement this in your classes that extend this
       * class.
       *
       * @param data A Turbine RunData object.
       * @exception Exception, a generic exception.
       */
      public abstract void doPerform(RunData data)
                              throws Exception;
  
      /***
       * This overrides the default Action.perform() to execute the
       * doEvent() method.  If that fails, then it will execute the
       * doPerform() method instead.
       *
       * @param data A Turbine RunData object.
       * @exception Exception, a generic exception.
       */
      protected void perform(RunData data)
                      throws Exception
        {
  
          try
            {
              executeEvents(data, TurbineVelocity.getContext(data));
            }
          catch (NoSuchMethodException e)
            {
              doPerform(data);
            }
        }
  
      /***
       * This method should be called to execute the event based system.
       *
       * @param data A Turbine RunData object.
       * @param context context information.
       * @exception Exception, a generic exception.
       */
      public void executeEvents(RunData data, Context context)
                         throws Exception
       {
 
         // Name of the button.
         String theButton = null;
         
         // Portlet whom this action is a target of
         Portlet portlet = (Portlet) context.get(GenericMVCPortlet.PORTLET);
 
         // ParameterParser.
         ParameterParser pp = data.getParameters();
         String button = pp.convert(BUTTON);
 
         // Loop through and find the button.
         for (Enumeration e = pp.keys(); e.hasMoreElements();)
           {
 
             String key = (String) e.nextElement();
 
             if (key.startsWith(button))
               {
                 theButton = formatString(key);
 
                 break;
               }
           }
 
         if (theButton == null )
           {
             throw new NoSuchMethodException("ActionEvent: The button was null");
           }
 
  
 
 		if (!fireEvent(data, Context.class, context, theButton) && PortletSessionState.isMyRequest(data, portlet))
 		{
 			// Old JSP actions use Portlet instead of Context
 			// as their event method's 2nd parameter
 			if (!fireEvent(data, Portlet.class,
 				portlet,
 				theButton))
 			{
 				// Attempt to execut things the old way..
 				super.executeEvents(data);
 			}
 		}            
 
       }
       
     /***
      * Convenience method for firing portlet events.
 	 * @author <a href="mailto:weaver@apache.org">Scott T. Weaver</a>
      */
 	protected boolean fireEvent(RunData data, Class deltaClass, Object deltaValue, String theButton)		
 	{
 		try
 		{
 			// The arguments to the method to find.
 			Class[] classes = new Class[2];
 			classes[0] = RunData.class;
 			classes[1] = deltaClass;
 			
 			// The arguments to pass to the method to execute.
 			Object[] args = new Object[2];
 			
 			String methodKey = getClass().getName()+":"
 			                   +theButton+":"+classes[0].getName()
 			                   +":"+classes[1].getName();
 			
 			Method method = (Method)eventMethods.get(methodKey);
 			if(method == null)
 			{
 				method = getClass().getMethod(theButton, classes);
 				eventMethods.put(methodKey, method);
 			}
 			args[0] = data;
 			args[1] = deltaValue;
 			method.invoke(this, args);
 			return true;
 		}
 		catch (Exception e)
 		{
 			return false;
 		}
 		
 	}
       
      
   }