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;
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.functor.adapter.RightBoundPredicate;
24
25 /**
26 * {@link #test Tests} the reference (==) equality of its arguments.
27 *
28 * @param <L> the left argument type.
29 * @param <R> the right argument type.
30 * @version $Revision: 1160410 $ $Date: 2011-08-22 22:06:40 +0200 (Mon, 22 Aug 2011) $
31 * @author Matt Benson
32 */
33 public final class IsSame<L, R> implements BinaryPredicate<L, R>, Serializable {
34 // static attributes
35 // ------------------------------------------------------------------------
36 /**
37 * Basic IsSame<Object, Object> instance.
38 */
39 public static final IsSame<Object, Object> INSTANCE = IsSame.<Object, Object>instance();
40 /**
41 * serialVersionUID declaration.
42 */
43 private static final long serialVersionUID = 7024585699909734072L;
44
45 // constructor
46 // ------------------------------------------------------------------------
47 /**
48 * Create a new IsSame.
49 */
50 public IsSame() {
51 }
52
53 // predicate interface
54 // ------------------------------------------------------------------------
55 /**
56 * {@inheritDoc}
57 */
58 public boolean test(L left, R right) {
59 return left == right;
60 }
61
62 /**
63 * {@inheritDoc}
64 */
65 public boolean equals(Object that) {
66 return that instanceof IsSame<?, ?>;
67 }
68
69 /**
70 * {@inheritDoc}
71 */
72 public int hashCode() {
73 return "IsSame".hashCode();
74 }
75
76 /**
77 * {@inheritDoc}
78 */
79 public String toString() {
80 return "IsSame";
81 }
82
83 // static methods
84 // ------------------------------------------------------------------------
85 /**
86 * Get an IsSame instance.
87 * @param <L> the left argument type.
88 * @param <R> the right argument type.
89 * @return IsSame
90 */
91 public static <L, R> IsSame<L, R> instance() {
92 return new IsSame<L, R>();
93 }
94
95 /**
96 * Get an IsSame UnaryPredicate.
97 * @param <L> the left argument type.
98 * @param <R> the right argument type.
99 * @param object bound comparison object
100 * @return UnaryPredicate<L>
101 */
102 public static <L, R> UnaryPredicate<L> as(R object) {
103 return new RightBoundPredicate<L>(new IsSame<L, R>(), object);
104 }
105 }