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.collections4.functors;
18
19 import org.apache.commons.collections4.Transformer;
20
21 /**
22 * Transformer implementation that returns a clone of the input object.
23 * <p>
24 * Clone is performed using {@code PrototypeFactory.prototypeFactory(input).create()}.
25 * </p>
26 * <p>
27 * <b>WARNING:</b> from v4.1 onwards this class will <b>not</b> be serializable anymore
28 * in order to prevent potential remote code execution exploits. Please refer to
29 * <a href="https://issues.apache.org/jira/browse/COLLECTIONS-580">COLLECTIONS-580</a>
30 * for more details.
31 * </p>
32 *
33 * @since 3.0
34 */
35 public class CloneTransformer<T> implements Transformer<T, T> {
36
37 /** Singleton predicate instance */
38 @SuppressWarnings("rawtypes") // the singleton instance works for all types
39 public static final Transformer INSTANCE = new CloneTransformer<>();
40
41 /**
42 * Factory returning the singleton instance.
43 *
44 * @param <T> the type of the objects to be cloned
45 * @return the singleton instance
46 * @since 3.1
47 */
48 public static <T> Transformer<T, T> cloneTransformer() {
49 return INSTANCE;
50 }
51
52 /**
53 * Constructs a new instance.
54 */
55 private CloneTransformer() {
56 }
57
58 /**
59 * Transforms the input to result by cloning it.
60 *
61 * @param input the input object to transform
62 * @return the transformed result
63 */
64 @Override
65 public T transform(final T input) {
66 if (input == null) {
67 return null;
68 }
69 return PrototypeFactory.prototypeFactory(input).create();
70 }
71
72 }