/*
    * 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.MethodInfo;
  import javax.faces.FacesWrapper;
  import javax.faces.context.FacesContext;
  import javax.faces.view.Location;
  
  /**
   * A MethodExpression that contains the original MethodExpression and
   * the Location of the facelet file from which the MethodExpression was
   * created. This is needed when the current composite component (cc) 
   * has to be resolved by the MethodExpression, because #{cc} refers to the
   * composite component which is implemented in the file the MethodExpression
   * comes from and not the one currently on top of the composite component stack.
   * 
   * This MethodExpression implementation passes through all methods to the delegate
   * MethodExpression, but saves the related composite component in a FacesContext attribute 
   * before the invocation of the method on the delegate and removes it afterwards.
   * 
   * @author Jakob Korherr (latest modification by $Author$)
   * @version $Revision$ $Date$
   */
  public class LocationMethodExpression extends MethodExpression 
      implements FacesWrapper<MethodExpression>, Externalizable, LocationAware
  {
  
      private static final long serialVersionUID = 1634644578979226893L;
      
      private Location location;
      private MethodExpression delegate;
      int ccLevel;
      
      public LocationMethodExpression()
      {
          super();
      }
      
      public LocationMethodExpression(Location location, MethodExpression delegate)
      {
          this.location = location;
          this.delegate = delegate;
          this.ccLevel = 0;
      }
  
      public LocationMethodExpression(Location location, MethodExpression delegate, int ccLevel)
      {
          this.location = location;
          this.delegate = delegate;
          this.ccLevel = ccLevel;
      }
  
      public Location getLocation()
      {
          return location;
      }
      
      public LocationMethodExpression apply(int newCCLevel)
      {
          if(this.ccLevel == newCCLevel)
          {
              return this;
          }
          else
          {
              return new LocationMethodExpression(this.location, this.delegate, newCCLevel);
          }
      }
      
      public LocationMethodExpression apply(int newCCLevel, Location newLocation)
      {
          if(this.ccLevel == newCCLevel && this.location.getPath().equals(newLocation.getPath()))
          {
              return this;
          }
         else
         {
             return new LocationMethodExpression(newLocation, this.delegate, newCCLevel);
         }
     }
     
     @Override
     public MethodInfo getMethodInfo(ELContext context)
     {
         FacesContext facesContext = (FacesContext) context.getContext(FacesContext.class);
         CompositeComponentELUtils.saveCompositeComponentForResolver(facesContext, location, ccLevel);
         try
         {
             return delegate.getMethodInfo(context);
         }
         finally
         {
             CompositeComponentELUtils.removeCompositeComponentForResolver(facesContext);
         }
     }
 
     @Override
     public Object invoke(ELContext context, Object[] params)
     {
         FacesContext facesContext = (FacesContext) context.getContext(FacesContext.class);
         CompositeComponentELUtils.saveCompositeComponentForResolver(facesContext, location, ccLevel);
         try
         {
             return delegate.invoke(context, params);
         }
         finally
         {
             CompositeComponentELUtils.removeCompositeComponentForResolver(facesContext);
         }
     }
 
     @Override
     public boolean equals(Object obj)
     {
         return delegate.equals(obj);
     }
 
     @Override
     public String getExpressionString()
     {
         return delegate.getExpressionString();
     }
 
     @Override
     public int hashCode()
     {
         return delegate.hashCode();
     }
 
     @Override
     public boolean isLiteralText()
     {
         return delegate.isLiteralText();
     }
 
     public MethodExpression getWrapped()
     {
         return delegate;
     }
     
     public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
     {
         this.delegate = (MethodExpression) in.readObject();
         this.location = (Location) in.readObject();
         this.ccLevel = in.readInt();
     }
 
     public void writeExternal(ObjectOutput out) throws IOException
     {
         out.writeObject(this.delegate);
         out.writeObject(this.location);
         out.writeInt(this.ccLevel);
     }
 
 }