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