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 * <strong>WARNING:</strong> from v4.1 onwards this class will <strong>not</strong> 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 * @param <T> the type of the input and result to the function.
34 * @since 3.0
35 */
36 public class CloneTransformer<T> implements Transformer<T, T> {
37
38 /** Singleton predicate instance */
39 @SuppressWarnings("rawtypes") // the singleton instance works for all types
40 public static final Transformer INSTANCE = new CloneTransformer<>();
41
42 /**
43 * Factory returning the singleton instance.
44 *
45 * @param <T> the type of the objects to be cloned
46 * @return the singleton instance
47 * @since 3.1
48 */
49 public static <T> Transformer<T, T> cloneTransformer() {
50 return INSTANCE;
51 }
52
53 /**
54 * Constructs a new instance.
55 */
56 private CloneTransformer() {
57 }
58
59 /**
60 * Transforms the input to result by cloning it.
61 *
62 * @param input the input object to transform
63 * @return the transformed result
64 */
65 @Override
66 public T transform(final T input) {
67 if (input == null) {
68 return null;
69 }
70 return PrototypeFactory.prototypeFactory(input).get();
71 }
72
73 }