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 * https://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
21 import org.apache.commons.collections4.Closure;
22 import org.apache.commons.collections4.Transformer;
23
24 /**
25 * Closure implementation that calls a Transformer using the input object
26 * and ignore the result.
27 *
28 * @param <T> The type of the input to the operation.
29 * @since 3.0
30 */
31 public class TransformerClosure<T> implements Closure<T>, Serializable {
32
33 /** Serial version UID */
34 private static final long serialVersionUID = -5194992589193388969L;
35
36 /**
37 * Factory method that performs validation.
38 * <p>
39 * A null transformer will return the {@code NOPClosure}.
40 * </p>
41 *
42 * @param <E> The type that the closure acts on
43 * @param transformer The transformer to call, null means nop
44 * @return The {@code transformer} closure
45 */
46 public static <E> Closure<E> transformerClosure(final Transformer<? super E, ?> transformer) {
47 if (transformer == null) {
48 return NOPClosure.<E>nopClosure();
49 }
50 return new TransformerClosure<>(transformer);
51 }
52
53 /** The transformer to wrap */
54 private final Transformer<? super T, ?> iTransformer;
55
56 /**
57 * Constructor that performs no validation.
58 * Use {@code transformerClosure} if you want that.
59 *
60 * @param transformer The transformer to call, not null
61 */
62 public TransformerClosure(final Transformer<? super T, ?> transformer) {
63 iTransformer = transformer;
64 }
65
66 /**
67 * Executes the closure by calling the decorated transformer.
68 *
69 * @param input The input object
70 */
71 @Override
72 public void execute(final T input) {
73 iTransformer.apply(input);
74 }
75
76 /**
77 * Gets the transformer.
78 *
79 * @return The transformer
80 * @since 3.1
81 */
82 public Transformer<? super T, ?> getTransformer() {
83 return iTransformer;
84 }
85
86 }