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.adapter;
18
19 import java.io.Serializable;
20
21 import org.apache.commons.functor.BinaryPredicate;
22 import org.apache.commons.functor.UnaryPredicate;
23 import org.apache.commons.lang3.Validate;
24
25 /**
26 * Adapts a
27 * {@link UnaryPredicate UnaryPredicate}
28 * to the
29 * {@link BinaryPredicate BinaryPredicate} interface
30 * by ignoring the second binary argument.
31 * <p/>
32 * Note that although this class implements
33 * {@link Serializable}, a given instance will
34 * only be truly <code>Serializable</code> if the
35 * underlying functor is. Attempts to serialize
36 * an instance whose delegate is not
37 * <code>Serializable</code> will result in an exception.
38 *
39 * @param <L> the left argument type.
40 * @param <R> the right argument type.
41 * @version $Revision: 1365377 $ $Date: 2012-07-24 21:59:23 -0300 (Tue, 24 Jul 2012) $
42 */
43 public final class IgnoreRightPredicate<L, R> implements BinaryPredicate<L, R>, Serializable {
44 /**
45 * serialVersionUID declaration.
46 */
47 private static final long serialVersionUID = -4236624667788627722L;
48 /** The {@link UnaryPredicate UnaryPredicate} I'm wrapping. */
49 private final UnaryPredicate<? super L> predicate;
50
51 /**
52 * Create a new IgnoreRightPredicate.
53 * @param predicate left
54 */
55 public IgnoreRightPredicate(UnaryPredicate<? super L> predicate) {
56 this.predicate = Validate.notNull(predicate, "UnaryPredicate argument was null");
57 }
58
59 /**
60 * {@inheritDoc}
61 */
62 public boolean test(L left, R right) {
63 return predicate.test(left);
64 }
65
66 /**
67 * {@inheritDoc}
68 */
69 @Override
70 public boolean equals(Object that) {
71 return that == this || (that instanceof IgnoreRightPredicate<?, ?>
72 && equals((IgnoreRightPredicate<?, ?>) that));
73 }
74
75 /**
76 * Learn whether a given IgnoreRightPredicate is equal to this.
77 * @param that IgnoreRightPredicate to test
78 * @return boolean
79 */
80 public boolean equals(IgnoreRightPredicate<?, ?> that) {
81 return null != that && predicate.equals(that.predicate);
82 }
83
84 /**
85 * {@inheritDoc}
86 */
87 @Override
88 public int hashCode() {
89 int hash = "IgnoreRightPredicate".hashCode();
90 hash ^= predicate.hashCode();
91 return hash;
92 }
93
94 /**
95 * {@inheritDoc}
96 */
97 @Override
98 public String toString() {
99 return "IgnoreRightPredicate<" + predicate + ">";
100 }
101
102 /**
103 * Adapt a UnaryPredicate as an IgnoreRightPredicate.
104 * @param <L> left type
105 * @param <R> right type
106 * @param predicate to adapt
107 * @return IgnoreRightPredicate<L, R>
108 */
109 public static <L, R> IgnoreRightPredicate<L, R> adapt(UnaryPredicate<? super L> predicate) {
110 return null == predicate ? null : new IgnoreRightPredicate<L, R>(predicate);
111 }
112
113 }