/*
    * 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.el;
  
  import java.io.Externalizable;
  import java.io.IOException;
  import java.io.ObjectInput;
  import java.io.ObjectOutput;
  
  import javax.el.ELContext;
  import javax.el.MethodExpression;
  import javax.el.ValueExpression;
  import javax.faces.FacesWrapper;
  import javax.faces.context.FacesContext;
  import javax.faces.event.AbortProcessingException;
  import javax.faces.event.ValueChangeEvent;
  import javax.faces.event.ValueChangeListener;
  
  /**
   *
   * @author Leonardo Uribe
   */
  public class RedirectMethodExpressionValueExpressionValueChangeListener
         implements ValueChangeListener, FacesWrapper<ValueExpression>, Externalizable
  {
      private ValueExpression valueExpression;
  
      public RedirectMethodExpressionValueExpressionValueChangeListener()
      {
      }
      
      public RedirectMethodExpressionValueExpressionValueChangeListener(ValueExpression valueExpression)
      {
          this.valueExpression = valueExpression;
      }
  
      public void processValueChange(ValueChangeEvent event) throws AbortProcessingException
      {
          getMethodExpression().invoke(FacesContext.getCurrentInstance().getELContext(), new Object[]{event});
      }
  
      private MethodExpression getMethodExpression()
      {
          return getMethodExpression(FacesContext.getCurrentInstance().getELContext());
      }
      
      private MethodExpression getMethodExpression(ELContext context)
      {
          Object meOrVe = valueExpression.getValue(context);
          if (meOrVe instanceof MethodExpression)
          {
              return (MethodExpression) meOrVe;
          }
          else if (meOrVe instanceof ValueExpression)
          {
              while (meOrVe != null && meOrVe instanceof ValueExpression)
              {
                  meOrVe = ((ValueExpression)meOrVe).getValue(context);
              }
              return (MethodExpression) meOrVe;
          }
          else
          {
              return null;
          }
      }
  
      public ValueExpression getWrapped()
      {
          return valueExpression;
      }
      public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
      {
          this.valueExpression = (ValueExpression) in.readObject();
      }
  
      public void writeExternal(ObjectOutput out) throws IOException
      {
          out.writeObject(this.valueExpression);
      }
  
  }