/*
    * 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.view.facelets.tag.jsf;
  
  import javax.el.MethodExpression;
  import javax.faces.component.PartialStateHolder;
  import javax.faces.context.FacesContext;
  import javax.faces.event.MethodExpressionValueChangeListener;
  
  public class PartialMethodExpressionValueChangeListener extends MethodExpressionValueChangeListener
      implements PartialStateHolder
  {
      private boolean _initialStateMarked;
  
      
      public PartialMethodExpressionValueChangeListener()
      {
          super();
      }
  
      public PartialMethodExpressionValueChangeListener(MethodExpression methodExpression1,
              MethodExpression methodExpression2)
      {
          super(methodExpression1, methodExpression2);
      }
  
      public PartialMethodExpressionValueChangeListener(MethodExpression methodExpression)
      {
          super(methodExpression);
      }
  
      public void clearInitialState()
      {
          _initialStateMarked = false;
      }
  
      public boolean initialStateMarked()
      {
          return _initialStateMarked;
      }
  
      public void markInitialState()
      {
          _initialStateMarked = true;
      }
  
      public void restoreState(FacesContext context, Object state)
      {
          if (state == null)
          {
              return;
          }
          super.restoreState(context, state);
      }
  
      public Object saveState(FacesContext context)
      {
          if (initialStateMarked())
          {
              return null;
          }
          return super.saveState(context);
      }
  }