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;
020
021/**
022 *
023 * <p>The implementation of the not operator
024 * 
025 * @author Nathan Abramson - Art Technology Group
026 * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: bayard $
027 **/
028
029public class NotOperator
030  extends UnaryOperator
031{
032  //-------------------------------------
033  // Singleton
034  //-------------------------------------
035
036  public static final NotOperator SINGLETON =
037    new NotOperator ();
038
039  //-------------------------------------
040  /**
041   *
042   * Constructor
043   **/
044  public NotOperator ()
045  {
046  }
047
048  //-------------------------------------
049  // Expression methods
050  //-------------------------------------
051  /**
052   *
053   * Returns the symbol representing the operator
054   **/
055  public String getOperatorSymbol ()
056  {
057    return "not";
058  }
059
060  //-------------------------------------
061  /**
062   *
063   * Applies the operator to the given value
064   **/
065  public Object apply (Object pValue)
066    throws ELException
067  {
068    // Coerce the value to a boolean
069    boolean val = Coercions.coerceToBoolean (pValue).booleanValue ();
070
071    return PrimitiveObjects.getBoolean (!val);
072  }
073
074  //-------------------------------------
075}