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.Predicate;
24
25 /**
26 * Closure implementation acts as an if statement calling one or other closure
27 * based on a predicate.
28 *
29 * @param <T> the type of the input to the operation.
30 * @since 3.0
31 */
32 public class IfClosure<T> implements Closure<T>, Serializable {
33
34 /** Serial version UID */
35 private static final long serialVersionUID = 3518477308466486130L;
36
37 /**
38 * Factory method that performs validation.
39 * <p>
40 * This factory creates a closure that performs no action when
41 * the predicate is false.
42 *
43 * @param <E> the type that the closure acts on
44 * @param predicate predicate to switch on
45 * @param trueClosure closure used if true
46 * @return the {@code if} closure
47 * @throws NullPointerException if either argument is null
48 * @since 3.2
49 */
50 public static <E> Closure<E> ifClosure(final Predicate<? super E> predicate, final Closure<? super E> trueClosure) {
51 return IfClosure.<E>ifClosure(predicate, trueClosure, NOPClosure.<E>nopClosure());
52 }
53 /**
54 * Factory method that performs validation.
55 *
56 * @param <E> the type that the closure acts on
57 * @param predicate predicate to switch on
58 * @param trueClosure closure used if true
59 * @param falseClosure closure used if false
60 * @return the {@code if} closure
61 * @throws NullPointerException if any argument is null
62 */
63 public static <E> Closure<E> ifClosure(final Predicate<? super E> predicate,
64 final Closure<? super E> trueClosure,
65 final Closure<? super E> falseClosure) {
66 return new IfClosure<>(Objects.requireNonNull(predicate, "predicate"),
67 Objects.requireNonNull(trueClosure, "trueClosure"),
68 Objects.requireNonNull(falseClosure, "falseClosure"));
69 }
70 /** The test */
71 private final Predicate<? super T> iPredicate;
72
73 /** The closure to use if true */
74 private final Closure<? super T> iTrueClosure;
75
76 /** The closure to use if false */
77 private final Closure<? super T> iFalseClosure;
78
79 /**
80 * Constructor that performs no validation.
81 * Use {@code ifClosure} if you want that.
82 * <p>
83 * This constructor creates a closure that performs no action when
84 * the predicate is false.
85 *
86 * @param predicate predicate to switch on, not null
87 * @param trueClosure closure used if true, not null
88 * @since 3.2
89 */
90 public IfClosure(final Predicate<? super T> predicate, final Closure<? super T> trueClosure) {
91 this(predicate, trueClosure, NOPClosure.nopClosure());
92 }
93
94 /**
95 * Constructor that performs no validation.
96 * Use {@code ifClosure} if you want that.
97 *
98 * @param predicate predicate to switch on, not null
99 * @param trueClosure closure used if true, not null
100 * @param falseClosure closure used if false, not null
101 */
102 public IfClosure(final Predicate<? super T> predicate, final Closure<? super T> trueClosure,
103 final Closure<? super T> falseClosure) {
104 iPredicate = predicate;
105 iTrueClosure = trueClosure;
106 iFalseClosure = falseClosure;
107 }
108
109 /**
110 * Executes the true or false closure according to the result of the predicate.
111 *
112 * @param input the input object
113 */
114 @Override
115 public void execute(final T input) {
116 if (iPredicate.test(input)) {
117 iTrueClosure.accept(input);
118 } else {
119 iFalseClosure.accept(input);
120 }
121 }
122
123 /**
124 * Gets the closure called when false.
125 *
126 * @return the closure
127 * @since 3.1
128 */
129 public Closure<? super T> getFalseClosure() {
130 return iFalseClosure;
131 }
132
133 /**
134 * Gets the predicate.
135 *
136 * @return the predicate
137 * @since 3.1
138 */
139 public Predicate<? super T> getPredicate() {
140 return iPredicate;
141 }
142
143 /**
144 * Gets the closure called when true.
145 *
146 * @return the closure
147 * @since 3.1
148 */
149 public Closure<? super T> getTrueClosure() {
150 return iTrueClosure;
151 }
152
153 }