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.BinaryPredicate;
22 import org.apache.commons.lang3.Validate;
23
24 /**
25 * {@link #test Tests} to the logical inverse
26 * of some other predicate.
27 * <p>
28 * Note that although this class implements
29 * {@link Serializable}, a given instance will
30 * only be truly <code>Serializable</code> if the
31 * underlying functor is. Attempts to serialize
32 * an instance whose delegate is not
33 * <code>Serializable</code> will result in an exception.
34 * </p>
35 * @param <L> the left argument type.
36 * @param <R> the right argument type.
37 * @version $Revision: 1365329 $ $Date: 2012-07-24 19:34:23 -0300 (Tue, 24 Jul 2012) $
38 */
39 public final class BinaryNot<L, R> implements BinaryPredicate<L, R>, Serializable {
40 /**
41 * serialVersionUID declaration.
42 */
43 private static final long serialVersionUID = -3488974286912054737L;
44 // attributes
45 // ------------------------------------------------------------------------
46 /**
47 * The adapted predicate.
48 */
49 private final BinaryPredicate<? super L, ? super R> predicate;
50
51 // constructor
52 // ------------------------------------------------------------------------
53 /**
54 * Create a new BinaryNot.
55 * @param predicate BinaryPredicate to negate
56 */
57 public BinaryNot(BinaryPredicate<? super L, ? super R> predicate) {
58 this.predicate = Validate.notNull(predicate, "BinaryPredicate argument was null");
59 }
60
61 // predicate interface
62 // ------------------------------------------------------------------------
63 /**
64 * {@inheritDoc}
65 */
66 public boolean test(L left, R right) {
67 return !(predicate.test(left, right));
68 }
69
70 /**
71 * {@inheritDoc}
72 */
73 @Override
74 public boolean equals(Object that) {
75 return that == this || (that instanceof BinaryNot<?, ?> && equals((BinaryNot<?, ?>) that));
76 }
77
78 /**
79 * Learn whether another BinaryNot is equal to this.
80 * @param that BinaryNot to test
81 * @return boolean
82 */
83 public boolean equals(BinaryNot<?, ?> that) {
84 return null != that && predicate.equals(that.predicate);
85 }
86
87 /**
88 * {@inheritDoc}
89 */
90 @Override
91 public int hashCode() {
92 int hash = "BinaryNot".hashCode();
93 hash ^= predicate.hashCode();
94 return hash;
95 }
96
97 /**
98 * {@inheritDoc}
99 */
100 @Override
101 public String toString() {
102 return "BinaryNot<" + predicate + ">";
103 }
104
105 // static
106 // ------------------------------------------------------------------------
107 /**
108 * Negate a BinaryPredicate.
109 * @param <L> the left argument type.
110 * @param <R> the right argument type.
111 * @param that BinaryPredicate to negate
112 * @return BinaryPredicate
113 */
114 public static <L, R> BinaryPredicate<L, R> not(BinaryPredicate<? super L, ? super R> that) {
115 return null == that ? null : new BinaryNot<L, R>(that);
116 }
117
118 }