/*
    * 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.ValueExpression;
  import javax.el.ValueReference;
  import javax.faces.FacesWrapper;
  import javax.faces.context.FacesContext;
  import javax.faces.view.Location;
  
  /**
   * A ValueExpression that contains the original ValueExpression and
   * the Location of the facelet file from which the ValueExpression was
   * created. This is needed when the current composite component (cc) 
   * has to be resolved by the ValueExpression, because #{cc} refers to the
   * composite component which is implemented in the file the ValueExpression
   * comes from and not the one currently on top of the composite component stack.
   * 
   * This ValueExpression implementation passes through all methods to the delegate
   * ValueExpression, 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 LocationValueExpression extends ValueExpression
      implements FacesWrapper<ValueExpression>, Externalizable
  {
      
      private static final long serialVersionUID = -5636849184764526288L;
      
      // location and delegate need to be available in LocationValueExpressionUEL
      Location location;
      ValueExpression delegate;
      int ccLevel;
      
      public LocationValueExpression()
      {
          super();
      }
      
      public LocationValueExpression(Location location, ValueExpression delegate)
      {
          this.location = location;
          this.delegate = delegate;
          this.ccLevel = 0;
      }
  
      public LocationValueExpression(Location location, ValueExpression delegate, int ccLevel)
      {
          this.location = location;
          this.delegate = delegate;
          this.ccLevel = ccLevel;
      }
      
      public Location getLocation()
      {
          return location;
      }
      
      public int getCCLevel()
      {
          return ccLevel;
      }
      
      public LocationValueExpression apply(int newCCLevel)
      {
          if(this.ccLevel == newCCLevel)
          {
              return this;
          }
          else
          {
              return new LocationValueExpression(this.location, this.delegate, newCCLevel);
          }
      }
      
     public LocationValueExpression apply(int newCCLevel, Location newLocation)
     {
         if(this.ccLevel == newCCLevel && this.location.getPath().equals(newLocation.getPath()))
         {
             return this;
         }
         else
         {
             return new LocationValueExpression(newLocation, this.delegate, newCCLevel);
         }
     }
         
     @Override
     public Class<?> getExpectedType()
     {
         return delegate.getExpectedType();
     }
 
     @Override
     public Class<?> getType(ELContext context)
     {
         FacesContext facesContext = (FacesContext) context.getContext(FacesContext.class);
         CompositeComponentELUtils.saveCompositeComponentForResolver(facesContext, location, ccLevel);
         try
         {
             return delegate.getType(context);
         }
         finally
         {
             CompositeComponentELUtils.removeCompositeComponentForResolver(facesContext);
         }
     }
 
     @Override
     public Object getValue(ELContext context)
     {
         FacesContext facesContext = (FacesContext) context.getContext(FacesContext.class);
         CompositeComponentELUtils.saveCompositeComponentForResolver(facesContext, location, ccLevel);
         try
         {
             return delegate.getValue(context);
         }
         finally
         {
             CompositeComponentELUtils.removeCompositeComponentForResolver(facesContext);
         }
     }
 
     @Override
     public boolean isReadOnly(ELContext context)
     {
         FacesContext facesContext = (FacesContext) context.getContext(FacesContext.class);
         CompositeComponentELUtils.saveCompositeComponentForResolver(facesContext, location, ccLevel);
         try
         {
             return delegate.isReadOnly(context);
         }
         finally
         {
             CompositeComponentELUtils.removeCompositeComponentForResolver(facesContext);
         }
     }
 
     @Override
     public void setValue(ELContext context, Object value)
     {
         FacesContext facesContext = (FacesContext) context.getContext(FacesContext.class);
         CompositeComponentELUtils.saveCompositeComponentForResolver(facesContext, location, ccLevel);
         try
         {
             delegate.setValue(context, value);
         }
         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();
     }
 
     @Override
     public ValueExpression getWrapped()
     {
         return delegate;
     }
     
     @Override
     public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
     {
         this.delegate = (ValueExpression) in.readObject();
         this.location = (Location) in.readObject();
         this.ccLevel = in.readInt();
     }
 
     @Override
     public void writeExternal(ObjectOutput out) throws IOException
     {
         out.writeObject(this.delegate);
         out.writeObject(this.location);
         out.writeInt(this.ccLevel);
     }
         
     @Override
     public ValueReference getValueReference(ELContext context)
     {
         FacesContext facesContext = (FacesContext) context.getContext(FacesContext.class);
         CompositeComponentELUtils.saveCompositeComponentForResolver(facesContext, location, ccLevel);
         try
         {
             return delegate.getValueReference(context);
         }
         finally
         {
             CompositeComponentELUtils.removeCompositeComponentForResolver(facesContext);
         }
     }
 }