/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
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 * 5. Products derived from this software may not be called "Apache"
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 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
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 */ 

package org.apache.commons.el;

import javax.servlet.jsp.el.VariableResolver;
import javax.servlet.jsp.el.ELException;
import javax.servlet.jsp.el.FunctionMapper;

/**
 *
 * <p>Represents a name that can be used as the first element of a
 * value.
 * 
 * @author Nathan Abramson - Art Technology Group
 * @author Shawn Bayern
 * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: luehe $
 **/

public class NamedValue
  extends Expression
{
  //-------------------------------------
  // Constants
  //-------------------------------------

  //-------------------------------------
  // Properties
  //-------------------------------------
  // property name

  String mName;
  public String getName ()
  { return mName; }

  //-------------------------------------
  /**
   *
   * Constructor
   **/
  public NamedValue (String pName)
  {
    mName = pName;
  }

  //-------------------------------------
  // Expression methods
  //-------------------------------------
  /**
   *
   * Returns the expression in the expression language syntax
   **/
  public String getExpressionString ()
  {
    return StringLiteral.toIdentifierToken (mName);
  }

  //-------------------------------------
  /**
   *
   * Evaluates by looking up the name in the VariableResolver
   **/
  public Object evaluate (VariableResolver pResolver,
			  FunctionMapper functions,
			  Logger pLogger)
    throws ELException
  {
    if (pResolver == null) {
      return null;
    }
    else {
      return pResolver.resolveVariable (mName);
    }
  }

  //-------------------------------------
}