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 015package org.apache.hivemind.conditional; 016 017import org.apache.hivemind.util.Defense; 018 019/** 020 * Evaluates a system property and returns true if its value is true. 021 * 022 * @author Howard M. Lewis Ship 023 * @since 1.1 024 */ 025public class PropertyEvaluator implements Evaluator 026{ 027 private String _propertyName; 028 029 public PropertyEvaluator(String propertyName) 030 { 031 Defense.notNull(propertyName, "propertyName"); 032 033 _propertyName = propertyName; 034 } 035 036 // For testing 037 038 String getPropertyName() 039 { 040 return _propertyName; 041 } 042 043 /** 044 * Invokes {@link org.apache.hivemind.conditional.EvaluationContext#isPropertySet(String)}. 045 */ 046 public boolean evaluate(EvaluationContext context, Node node) 047 { 048 return context.isPropertySet(_propertyName); 049 } 050 051}