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.collections4.functors;
18
19 import java.io.Serializable;
20
21 import org.apache.commons.collections4.Predicate;
22
23 /**
24 * Predicate implementation that returns true if the input is the same object
25 * as the one stored in this predicate.
26 *
27 * @param <T> the type of the input to the predicate.
28 * @since 3.0
29 */
30 public final class IdentityPredicate<T> extends AbstractPredicate<T> implements Serializable {
31
32 /** Serial version UID */
33 private static final long serialVersionUID = -89901658494523293L;
34
35 /**
36 * Creates the identity predicate.
37 *
38 * @param <T> the type that the predicate queries
39 * @param object the object to compare to
40 * @return the predicate
41 */
42 public static <T> Predicate<T> identityPredicate(final T object) {
43 if (object == null) {
44 return NullPredicate.<T>nullPredicate();
45 }
46 return new IdentityPredicate<>(object);
47 }
48
49 /** The value to compare to */
50 private final T iValue;
51
52 /**
53 * Constructor that performs no validation.
54 * Use {@code identityPredicate} if you want that.
55 *
56 * @param object the object to compare to
57 */
58 public IdentityPredicate(final T object) {
59 iValue = object;
60 }
61
62 /**
63 * Gets the value.
64 *
65 * @return the value
66 * @since 3.1
67 */
68 public T getValue() {
69 return iValue;
70 }
71
72 /**
73 * Evaluates the predicate returning true if the input object is identical to
74 * the stored object.
75 *
76 * @param object the input object
77 * @return true if input is the same object as the stored value
78 */
79 @Override
80 public boolean test(final T object) {
81 return iValue == object;
82 }
83
84 }