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: 1345136 $ $Date: 2012-06-01 08:47:06 -0400 (Fri, 01 Jun 2012) $
31 */
32 public final class IsSame<L, R> implements BinaryPredicate<L, R>, Serializable {
33 // static attributes
34 // ------------------------------------------------------------------------
35 /**
36 * Basic IsSame<Object, Object> instance.
37 */
38 public static final IsSame<Object, Object> INSTANCE = IsSame.<Object, Object>instance();
39 /**
40 * serialVersionUID declaration.
41 */
42 private static final long serialVersionUID = 7024585699909734072L;
43
44 // constructor
45 // ------------------------------------------------------------------------
46 /**
47 * Create a new IsSame.
48 */
49 public IsSame() {
50 }
51
52 // predicate interface
53 // ------------------------------------------------------------------------
54 /**
55 * {@inheritDoc}
56 */
57 public boolean test(L left, R right) {
58 return left == right;
59 }
60
61 /**
62 * {@inheritDoc}
63 */
64 @Override
65 public boolean equals(Object that) {
66 return that instanceof IsSame<?, ?>;
67 }
68
69 /**
70 * {@inheritDoc}
71 */
72 @Override
73 public int hashCode() {
74 return "IsSame".hashCode();
75 }
76
77 /**
78 * {@inheritDoc}
79 */
80 @Override
81 public String toString() {
82 return "IsSame";
83 }
84
85 // static methods
86 // ------------------------------------------------------------------------
87 /**
88 * Get an IsSame instance.
89 * @param <L> the left argument type.
90 * @param <R> the right argument type.
91 * @return IsSame
92 */
93 public static <L, R> IsSame<L, R> instance() {
94 return new IsSame<L, R>();
95 }
96
97 /**
98 * Get an IsSame UnaryPredicate.
99 * @param <L> the left argument type.
100 * @param <R> the right argument type.
101 * @param object bound comparison object
102 * @return UnaryPredicate<L>
103 */
104 public static <L, R> UnaryPredicate<L> as(R object) {
105 return new RightBoundPredicate<L>(new IsSame<L, R>(), object);
106 }
107 }