/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.

  */

 package org.apache.myfaces.taglib.core;

 import javax.el.ELException;

 import javax.el.ValueExpression;

 import javax.faces.FacesException;

 import javax.faces.component.StateHolder;

 import javax.faces.context.FacesContext;

 import javax.faces.event.AbortProcessingException;

 import javax.faces.event.ActionEvent;

 import javax.faces.event.ActionListener;

 import javax.faces.event.ValueChangeEvent;

 import javax.faces.event.ValueChangeListener;

 /**

  * This class is used in conjunction with ValueChangeListenerTag. 

  * 

  * When a tag like this is in a jsp page:

  * 

  * <f:valueChangeListener binding="#{mybean}"/>

  *  

  *  or

  *  

  * <f:valueChangeListener type="#{'anyid'}" binding="#{mybean}"/>

  * 

  * The value of mybean could be already on the context, so this

  * converter avoid creating a new variable and use the previous one.

  * 

  * @author Leonardo Uribe (latest modification by $Author: lu4242 $)

  * @version $Revision: 600199 $ $Date: 2007-12-01 16:28:15 -0500 (Sat, 01 Dec 2007) $

  */

 public class DelegateValueChangeListener implements ValueChangeListener, StateHolder

 {

     private ValueExpression _type;

     private ValueExpression _binding;

     public DelegateValueChangeListener()

     {

     }

     public DelegateValueChangeListener(ValueExpression type, ValueExpression binding)

     {

         super();

         _type = type;

         _binding = binding;

     }

     public boolean isTransient()

     {

         return false;

     }

     public void restoreState(FacesContext facesContext, Object state)

     {

         Object[] values = (Object[]) state;

         _type = (ValueExpression) values[0];

         _binding = (ValueExpression) values[1];

     }

     public Object saveState(FacesContext facesContext)

     {

         Object[] values = new Object[2];

         values[0] = _type;

         values[1] = _binding;

         return values;

     }

     public void setTransient(boolean arg0)

     {

         // Do nothing        

     }

     private ValueChangeListener _getDelegate()

     {

         return _createValueChangeListener();

     }

     private ValueChangeListener _createValueChangeListener()

     {

         FacesContext facesContext = FacesContext.getCurrentInstance();

         ValueChangeListener listener = null;

         // type and/or binding must be specified

         try

         {

             if (null != _binding)

             {

                 try

                 {

                     listener = (ValueChangeListener) _binding.getValue(facesContext

                             .getELContext());

                     if (null != listener)

                     {

                         return listener;

                     }

                 }

                 catch (ELException e)

                 {

                     //throw new JspException("Exception while evaluating the binding attribute of Component "

                     //        + component.getId(), e);

                 }

             }

             if (null != _type)

             {

                 String className;

                 if (_type.isLiteralText())

                 {

                     className = _type.getExpressionString();

                 }

                 else

                 {

                     className = (String) _type.getValue(facesContext

                             .getELContext());

                 }

                 listener = null;

                 //listener = (ActionListener) ClassUtils.newInstance(className);

                 if (null != _binding)

                 {

                     try

                     {

                         _binding

                                 .setValue(facesContext.getELContext(), listener);

                     }

                     catch (ELException e)

                     {

                         //throw new JspException("Exception while evaluating the binding attribute of Component "

                         //        + component.getId(), e);

                     }

                 }

                 return listener;

             }

         }

         catch (ClassCastException e)

         {

             throw new FacesException(e);

         }

         return listener;

     }

     public void processValueChange(ValueChangeEvent event)

             throws AbortProcessingException

     {

         _getDelegate().processValueChange(event);

     }

 }