/*
    * 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 java.io.Serializable;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import javax.el.ELException;
  import javax.faces.context.FacesContext;
  import javax.faces.event.ComponentSystemEvent;
  import javax.faces.event.ComponentSystemEventListener;
  
  /**
   * MyFaces specific listener used to clear all component binding if
   * normal navigation occur during a POST request.
   * 
   * @author Leonardo Uribe
   * @since 2.0.6
   *
   */
  public class ClearBindingValueExpressionListener implements ComponentSystemEventListener, Serializable
  {
      
      /**
       * 
       */
      private static final long serialVersionUID = -6066524284031941519L;
      
      public ClearBindingValueExpressionListener()
      {
          super();
      }
  
      public void processEvent(ComponentSystemEvent event)
      {
          try
          {
              event.getComponent().getValueExpression("binding").setValue(
                      FacesContext.getCurrentInstance().getELContext(), null);
          }
          catch(ELException e)
          {
              Logger log = Logger.getLogger(ClearBindingValueExpressionListener.class.getName());
              if (log.isLoggable(Level.FINE))
              {
                  log.log(Level.FINE, "Cannot reset binding for: " + event.getComponent().getClientId(), e);
              }
          }
          catch(NullPointerException e)
          {
              Logger log = Logger.getLogger(ClearBindingValueExpressionListener.class.getName());
              if (log.isLoggable(Level.FINE))
              {
                  log.log(Level.FINE, "Cannot reset binding for: " + event.getComponent().getClientId(), e);
              }
          }
      }
  
  }