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Java > Open Source Codes > org > apache > commons > collections > functors > TransformerClosure


1 /*
2  * Copyright 2001-2004 The Apache Software Foundation
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.apache.commons.collections.functors;
17
18 import java.io.Serializable JavaDoc;
19
20 import org.apache.commons.collections.Closure;
21 import org.apache.commons.collections.Transformer;
22
23 /**
24  * Closure implementation that calls a Transformer using the input object
25  * and ignore the result.
26  *
27  * @since Commons Collections 3.0
28  * @version $Revision: 1.5 $ $Date: 2004/05/16 11:47:38 $
29  *
30  * @author Stephen Colebourne
31  */
32 public class TransformerClosure implements Closure, Serializable JavaDoc {
33
34     /** Serial version UID */
35     static final long serialVersionUID = -5194992589193388969L;
36
37     /** The transformer to wrap */
38     private final Transformer iTransformer;
39
40     /**
41      * Factory method that performs validation.
42      * <p>
43      * A null transformer will return the <code>NOPClosure</code>.
44      *
45      * @param transformer the transformer to call, null means nop
46      * @return the <code>transformer</code> closure
47      */
48     public static Closure getInstance(Transformer transformer) {
49         if (transformer == null) {
50             return NOPClosure.INSTANCE;
51         }
52         return new TransformerClosure(transformer);
53     }
54
55     /**
56      * Constructor that performs no validation.
57      * Use <code>getInstance</code> if you want that.
58      *
59      * @param transformer the transformer to call, not null
60      */
61     public TransformerClosure(Transformer transformer) {
62         super();
63         iTransformer = transformer;
64     }
65
66     /**
67      * Executes the closure by calling the decorated transformer.
68      *
69      * @param input the input object
70      */
71     public void execute(Object JavaDoc input) {
72         iTransformer.transform(input);
73     }
74
75     /**
76      * Gets the transformer.
77      *
78      * @return the transformer
79      * @since Commons Collections 3.1
80      */
81     public Transformer getTransformer() {
82         return iTransformer;
83     }
84
85 }
86
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