1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.collections.functors;
18
19 import java.io.Serializable;
20
21 import org.apache.commons.collections.Transformer;
22
23 /**
24 * Transformer implementation that returns the result of calling
25 * <code>String.valueOf</code> on the input object.
26 *
27 * @since 3.0
28 * @version $Id: StringValueTransformer.java 1435965 2013-01-20 21:13:18Z tn $
29 */
30 public final class StringValueTransformer<T> implements Transformer<T, String>, Serializable {
31
32 /** Serial version UID */
33 private static final long serialVersionUID = 7511110693171758606L;
34
35 /** Singleton predicate instance */
36 public static final Transformer<Object, String> INSTANCE = new StringValueTransformer<Object>();
37
38 /**
39 * Factory returning the singleton instance.
40 *
41 * @param <T> the input type
42 * @return the singleton instance
43 * @since 3.1
44 */
45 @SuppressWarnings("unchecked")
46 public static <T> Transformer<T, String> stringValueTransformer() {
47 return (Transformer<T, String>) INSTANCE;
48 }
49
50 /**
51 * Restricted constructor.
52 */
53 private StringValueTransformer() {
54 super();
55 }
56
57 /**
58 * Transforms the input to result by calling <code>String.valueOf</code>.
59 *
60 * @param input the input object to transform
61 * @return the transformed result
62 */
63 public String transform(final T input) {
64 return String.valueOf(input);
65 }
66
67 private Object readResolve() {
68 return INSTANCE;
69 }
70
71 }