001    // Copyright 2004, 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.hivemind.conditional;
016    
017    /**
018     * Evaluates the left child of its peer Node and inverts the result.
019     * 
020     * @author Howard M. Lewis Ship
021     * @since 1.1
022     */
023    public class NotEvaluator implements Evaluator
024    {
025        public boolean evaluate(EvaluationContext context, Node node)
026        {
027            return !node.getLeft().evaluate(context);
028        }
029    }