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Java > Open Source Codes > org > apache > hivemind > conditional > PropertyEvaluator


1 // Copyright 2004, 2005 The Apache Software Foundation
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 package org.apache.hivemind.conditional;
16
17 import org.apache.hivemind.util.Defense;
18
19 /**
20  * Evaluates a system property and returns true if its value is true.
21  *
22  * @author Howard M. Lewis Ship
23  * @since 1.1
24  */
25 public class PropertyEvaluator implements Evaluator
26 {
27     private String JavaDoc _propertyName;
28
29     public PropertyEvaluator(String JavaDoc propertyName)
30     {
31         Defense.notNull(propertyName, "propertyName");
32
33         _propertyName = propertyName;
34     }
35
36     // For testing
37
38     String JavaDoc getPropertyName()
39     {
40         return _propertyName;
41     }
42
43     /**
44      * Invokes {@link org.apache.hivemind.conditional.EvaluationContext#isPropertySet(String)}.
45      */
46     public boolean evaluate(EvaluationContext context, Node node)
47     {
48         return context.isPropertySet(_propertyName);
49     }
50
51 }
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