/*
    * 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.jstl.core;
  
  import java.io.Serializable;
  import java.util.Map;
  
  import javax.el.ELContext;
  import javax.el.ValueExpression;
  
  /**
   * @author Jacob Hookom
   * @version $Id$
   */
  public final class MappedValueExpression extends ValueExpression
  {
      private final static class Entry implements Map.Entry, Serializable
      {
          private final Map src;
          private final Object key;
  
          public Entry(Map src, Object key)
          {
              this.src = src;
              this.key = key;
          }
  
          @Override
          public Object getKey()
          {
              return key;
          }
  
          @Override
          public Object getValue()
          {
              return src.get(key);
          }
  
          @Override
          public Object setValue(Object value)
          {
              return src.put(key, value);
          }
  
      }
  
      private static final long serialVersionUID = 1L;
  
      private final Object key;
  
      private final ValueExpression orig;
  
      public MappedValueExpression(ValueExpression orig, Map.Entry entry)
      {
          this.orig = orig;
          this.key = entry.getKey();
      }
  
      @Override
      public Object getValue(ELContext context)
      {
          Object base = this.orig.getValue(context);
          if (base != null)
          {
              context.setPropertyResolved(true);
              return new Entry((Map) base, key);
  
          }
          return null;
      }
  
      @Override
      public void setValue(ELContext context, Object value)
      {
          Object base = this.orig.getValue(context);
          if (base != null)
          {
              context.setPropertyResolved(false);
              context.getELResolver().setValue(context, base, key, value);
          }
      }
  
     @Override
     public boolean isReadOnly(ELContext context)
     {
         Object base = this.orig.getValue(context);
         if (base != null)
         {
             context.setPropertyResolved(false);
             return context.getELResolver().isReadOnly(context, base, key);
         }
         return true;
     }
 
     @Override
     public Class getType(ELContext context)
     {
         Object base = this.orig.getValue(context);
         if (base != null)
         {
             context.setPropertyResolved(false);
             return context.getELResolver().getType(context, base, key);
         }
         return null;
     }
 
     @Override
     public Class getExpectedType()
     {
         return Object.class;
     }
 
     @Override
     public String getExpressionString()
     {
         return this.orig.getExpressionString();
     }
 
     @Override
     public boolean equals(Object obj)
     {
         return this.orig.equals(obj);
     }
 
     @Override
     public int hashCode()
     {
         return 0;
     }
 
     @Override
     public boolean isLiteralText()
     {
         return false;
     }
 
 }