Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
ConditionalPredicate |
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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.functor.core.composite; | |
18 | ||
19 | import java.io.Serializable; | |
20 | ||
21 | import org.apache.commons.functor.Predicate; | |
22 | ||
23 | /** | |
24 | * A {@link Predicate Predicate} | |
25 | * similiar to Java's "ternary" | |
26 | * or "conditional" operator (<code>? :</code>). | |
27 | * Given three {@link Predicate predicates} | |
28 | * <i>p</i>, <i>q</i>, <i>r</i>, | |
29 | * {@link #test tests} | |
30 | * to | |
31 | * <code>p.test() ? q.test() : r.test()</code>. | |
32 | * <p> | |
33 | * Note that although this class implements | |
34 | * {@link Serializable}, a given instance will | |
35 | * only be truly <code>Serializable</code> if all the | |
36 | * underlying functors are. Attempts to serialize | |
37 | * an instance whose delegates are not all | |
38 | * <code>Serializable</code> will result in an exception. | |
39 | * </p> | |
40 | * @version $Revision: 1166388 $ $Date: 2011-09-07 22:29:02 +0200 (Wed, 07 Sep 2011) $ | |
41 | * @author Rodney Waldhoff | |
42 | */ | |
43 | public final class ConditionalPredicate implements Predicate, Serializable { | |
44 | /** | |
45 | * serialVersionUID declaration. | |
46 | */ | |
47 | private static final long serialVersionUID = 7333505000745854098L; | |
48 | ||
49 | /** Base hash integer used to shift hash */ | |
50 | private static final int HASH_SHIFT = 4; | |
51 | // attributes | |
52 | // ------------------------------------------------------------------------ | |
53 | private final Predicate ifPred; | |
54 | private final Predicate thenPred; | |
55 | private final Predicate elsePred; | |
56 | ||
57 | // constructor | |
58 | // ------------------------------------------------------------------------ | |
59 | /** | |
60 | * Create a new ConditionalPredicate. | |
61 | * @param ifPred if | |
62 | * @param thenPred then | |
63 | * @param elsePred else | |
64 | */ | |
65 | 20 | public ConditionalPredicate(Predicate ifPred, Predicate thenPred, Predicate elsePred) { |
66 | 20 | if (ifPred == null || thenPred == null || elsePred == null) { |
67 | 0 | throw new IllegalArgumentException("One or more Predicate arguments was null"); |
68 | } | |
69 | 20 | this.ifPred = ifPred; |
70 | 20 | this.thenPred = thenPred; |
71 | 20 | this.elsePred = elsePred; |
72 | 20 | } |
73 | ||
74 | // predicate interface | |
75 | // ------------------------------------------------------------------------ | |
76 | /** | |
77 | * {@inheritDoc} | |
78 | */ | |
79 | public boolean test() { | |
80 | 4 | return ifPred.test() ? thenPred.test() : elsePred.test(); |
81 | } | |
82 | ||
83 | /** | |
84 | * {@inheritDoc} | |
85 | */ | |
86 | public boolean equals(Object that) { | |
87 | 24 | return that == this || (that instanceof ConditionalPredicate && equals((ConditionalPredicate) that)); |
88 | } | |
89 | ||
90 | /** | |
91 | * Learn whether another ConditionalPredicate is equal to this. | |
92 | * @param that ConditionalPredicate to test | |
93 | * @return boolean | |
94 | */ | |
95 | public boolean equals(ConditionalPredicate that) { | |
96 | 18 | return null != that |
97 | && (null == ifPred ? null == that.ifPred : ifPred.equals(that.ifPred)) | |
98 | && (null == thenPred ? null == that.thenPred : thenPred.equals(that.thenPred)) | |
99 | && (null == elsePred ? null == that.elsePred : elsePred.equals(that.elsePred)); | |
100 | } | |
101 | ||
102 | /** | |
103 | * {@inheritDoc} | |
104 | */ | |
105 | public int hashCode() { | |
106 | 26 | int hash = "ConditionalPredicate".hashCode(); |
107 | 26 | if (null != ifPred) { |
108 | 26 | hash <<= HASH_SHIFT; |
109 | 26 | hash ^= ifPred.hashCode(); |
110 | } | |
111 | 26 | if (null != thenPred) { |
112 | 26 | hash <<= HASH_SHIFT; |
113 | 26 | hash ^= thenPred.hashCode(); |
114 | } | |
115 | 26 | if (null != elsePred) { |
116 | 26 | hash <<= HASH_SHIFT; |
117 | 26 | hash ^= elsePred.hashCode(); |
118 | } | |
119 | 26 | return hash; |
120 | } | |
121 | ||
122 | /** | |
123 | * {@inheritDoc} | |
124 | */ | |
125 | public String toString() { | |
126 | 18 | return "ConditionalPredicate<" + ifPred + "?" + thenPred + ":" + elsePred + ">"; |
127 | } | |
128 | ||
129 | } |