/*

  * 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.el.ValueExpression;

 import javax.faces.FacesWrapper;

 import javax.faces.context.FacesContext;

 /**

  * This MethodExpression contains a ValueExpression which resolves to 

  * the "real" MethodExpression that should be invoked. This is needed 

  * when the MethodExpression is on the parent composite component attribute map.

  * See FaceletViewDeclarationLanguage.retargetMethodExpressions() for details.

  * 

  * @author Jakob Korherr (latest modification by $Author$)

  * @version $Revision$ $Date$

  */

 public class ValueExpressionMethodExpression extends MethodExpression 

     implements FacesWrapper<ValueExpression>, Externalizable

 {

     private static final long serialVersionUID = -2847633717581167765L;

     private ValueExpression valueExpression;

     public ValueExpressionMethodExpression()

     {

     }

     public ValueExpressionMethodExpression(ValueExpression valueExpression)

     {

         this.valueExpression = valueExpression;   

     }

     @Override

     public MethodInfo getMethodInfo(ELContext context)

     {

         MethodExpression me = getMethodExpression(context);

         if (me != null)

         {

             return me.getMethodInfo(context);

         }

         return null;

     }

     @Override

     public Object invoke(ELContext context, Object[] params)

     {

         MethodExpression me = getMethodExpression(context);

         if (me != null)

         {        

             return me.invoke(context, params);

         }

         return null;

     }

     @Override

     public boolean equals(Object obj)

     {

         MethodExpression me = getMethodExpression();

         if (me != null)

         {        

             return me.equals(obj);

         }

         if (!(obj instanceof ValueExpressionMethodExpression))

         {

             return false;

         }

         ValueExpressionMethodExpression other = (ValueExpressionMethodExpression) obj;

         if ((this.valueExpression == null && other.valueExpression != null) || 

              (this.valueExpression != null && !this.valueExpression.equals(other.valueExpression)))

         {

             return false;

         }

         return true;

     }

     @Override

     public String getExpressionString()

     {

         //getMethodExpression().getExpressionString()

         return valueExpression.getExpressionString();

     }

     @Override

     public int hashCode()

     {

         MethodExpression me = getMethodExpression();

         if (me != null)

         {        

             return me.hashCode();

         }

         return valueExpression.hashCode();

     }

     @Override

     public boolean isLiteralText()

     {

         MethodExpression me = getMethodExpression();

         if (me != null)

         {

             return me.isLiteralText();

         }

         return valueExpression.isLiteralText();

     }

     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);

     }

 }