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 * @since 3.0
28 */
29 public final class IdentityPredicate<T> implements Predicate<T>, Serializable {
30
31 /** Serial version UID */
32 private static final long serialVersionUID = -89901658494523293L;
33
34 /**
35 * Factory to create the identity predicate.
36 *
37 * @param <T> the type that the predicate queries
38 * @param object the object to compare to
39 * @return the predicate
40 */
41 public static <T> Predicate<T> identityPredicate(final T object) {
42 if (object == null) {
43 return NullPredicate.<T>nullPredicate();
44 }
45 return new IdentityPredicate<>(object);
46 }
47
48 /** The value to compare to */
49 private final T iValue;
50
51 /**
52 * Constructor that performs no validation.
53 * Use {@code identityPredicate} if you want that.
54 *
55 * @param object the object to compare to
56 */
57 public IdentityPredicate(final T object) {
58 iValue = object;
59 }
60
61 /**
62 * Evaluates the predicate returning true if the input object is identical to
63 * the stored object.
64 *
65 * @param object the input object
66 * @return true if input is the same object as the stored value
67 */
68 @Override
69 public boolean evaluate(final T object) {
70 return iValue == object;
71 }
72
73 /**
74 * Gets the value.
75 *
76 * @return the value
77 * @since 3.1
78 */
79 public T getValue() {
80 return iValue;
81 }
82
83 }