001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.el;
018
019import javax.servlet.jsp.el.ELException;
020import javax.servlet.jsp.el.FunctionMapper;
021import javax.servlet.jsp.el.VariableResolver;
022
023/**
024 *
025 * <p>Represents a name that can be used as the first element of a
026 * value.
027 * 
028 * @author Nathan Abramson - Art Technology Group
029 * @author Shawn Bayern
030 * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: bayard $
031 **/
032
033public class NamedValue
034  extends Expression
035{
036  //-------------------------------------
037  // Constants
038  //-------------------------------------
039
040  //-------------------------------------
041  // Properties
042  //-------------------------------------
043  // property name
044
045  String mName;
046  public String getName ()
047  { return mName; }
048
049  //-------------------------------------
050  /**
051   *
052   * Constructor
053   **/
054  public NamedValue (String pName)
055  {
056    mName = pName;
057  }
058
059  //-------------------------------------
060  // Expression methods
061  //-------------------------------------
062  /**
063   *
064   * Returns the expression in the expression language syntax
065   **/
066  public String getExpressionString ()
067  {
068    return StringLiteral.toIdentifierToken (mName);
069  }
070
071  //-------------------------------------
072  /**
073   *
074   * Evaluates by looking up the name in the VariableResolver
075   **/
076  public Object evaluate (VariableResolver pResolver, FunctionMapper functions)
077    throws ELException
078  {
079    if (pResolver == null) {
080      return null;
081    }
082    else {
083      return pResolver.resolveVariable (mName);
084    }
085  }
086
087  public Expression bindFunctions(FunctionMapper functions) throws ELException {
088      return this;
089  }
090
091  //-------------------------------------
092}