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.collections.functors;
18
19 import java.io.Serializable;
20
21 import org.apache.commons.collections.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 * @version $Id: IdentityPredicate.java 1429905 2013-01-07 17:15:14Z ggregory $
29 */
30 public final class IdentityPredicate<T> implements Predicate<T>, Serializable {
31
32 /** Serial version UID */
33 private static final long serialVersionUID = -89901658494523293L;
34
35 /** The value to compare to */
36 private final T iValue;
37
38 /**
39 * Factory to create the identity predicate.
40 *
41 * @param <T> the type that the predicate queries
42 * @param object the object to compare to
43 * @return the predicate
44 * @throws IllegalArgumentException if the predicate is null
45 */
46 public static <T> Predicate<T> identityPredicate(final T object) {
47 if (object == null) {
48 return NullPredicate.<T>nullPredicate();
49 }
50 return new IdentityPredicate<T>(object);
51 }
52
53 /**
54 * Constructor that performs no validation.
55 * Use <code>getInstance</code> if you want that.
56 *
57 * @param object the object to compare to
58 */
59 public IdentityPredicate(final T object) {
60 super();
61 iValue = object;
62 }
63
64 /**
65 * Evaluates the predicate returning true if the input object is identical to
66 * the stored object.
67 *
68 * @param object the input object
69 * @return true if input is the same object as the stored value
70 */
71 public boolean evaluate(final T object) {
72 return iValue == object;
73 }
74
75 /**
76 * Gets the value.
77 *
78 * @return the value
79 * @since 3.1
80 */
81 public T getValue() {
82 return iValue;
83 }
84
85 }