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     */
017    package org.apache.commons.el;
018    
019    /**
020     *
021     * <p>An expression representing a boolean literal value
022     * 
023     * @author Nathan Abramson - Art Technology Group
024     * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: bayard $
025     **/
026    
027    public class BooleanLiteral
028      extends Literal
029    {
030      //-------------------------------------
031      // Member variables
032      //-------------------------------------
033    
034      public static final BooleanLiteral TRUE = new BooleanLiteral ("true");
035      public static final BooleanLiteral FALSE = new BooleanLiteral ("false");
036    
037      //-------------------------------------
038      /**
039       *
040       * Constructor
041       **/
042      public BooleanLiteral (String pToken)
043      {
044        super (getValueFromToken (pToken));
045      }
046    
047      //-------------------------------------
048      /**
049       *
050       * Parses the given token into the literal value
051       **/
052      static Object getValueFromToken (String pToken)
053      {
054        return
055          ("true".equals (pToken)) ?
056          Boolean.TRUE :
057          Boolean.FALSE;
058      }
059    
060      //-------------------------------------
061      // Expression methods
062      //-------------------------------------
063      /**
064       *
065       * Returns the expression in the expression language syntax
066       **/
067      public String getExpressionString ()
068      {
069        return (getValue () == Boolean.TRUE) ? "true" : "false";
070      }
071    
072      //-------------------------------------
073    }