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 java.io.Serializable;
20 import java.util.Objects;
21
22 import org.apache.commons.collections4.Closure;
23 import org.apache.commons.collections4.Transformer;
24
25 /**
26 * Transformer implementation that calls a Closure using the input object
27 * and then returns the input.
28 *
29 * @since 3.0
30 */
31 public class ClosureTransformer<T> implements Transformer<T, T>, Serializable {
32
33 /** Serial version UID */
34 private static final long serialVersionUID = 478466901448617286L;
35
36 /**
37 * Factory method that performs validation.
38 *
39 * @param <T> the type of the object to transform
40 * @param closure the closure to call, not null
41 * @return the {@code closure} transformer
42 * @throws NullPointerException if the closure is null
43 */
44 public static <T> Transformer<T, T> closureTransformer(final Closure<? super T> closure) {
45 return new ClosureTransformer<>(Objects.requireNonNull(closure, "closure"));
46 }
47
48 /** The closure to wrap */
49 private final Closure<? super T> iClosure;
50
51 /**
52 * Constructor that performs no validation.
53 * Use {@code closureTransformer} if you want that.
54 *
55 * @param closure the closure to call, not null
56 */
57 public ClosureTransformer(final Closure<? super T> closure) {
58 iClosure = closure;
59 }
60
61 /**
62 * Gets the closure.
63 *
64 * @return the closure
65 * @since 3.1
66 */
67 public Closure<? super T> getClosure() {
68 return iClosure;
69 }
70
71 /**
72 * Transforms the input to result by executing a closure.
73 *
74 * @param input the input object to transform
75 * @return the transformed result
76 */
77 @Override
78 public T transform(final T input) {
79 iClosure.execute(input);
80 return input;
81 }
82
83 }