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 import 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 */ 025 public 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 }