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 an instanceof
25 * the type stored in this predicate.
26 *
27 * @since 3.0
28 * @version $Id: InstanceofPredicate.java 1429905 2013-01-07 17:15:14Z ggregory $
29 */
30 public final class InstanceofPredicate implements Predicate<Object>, Serializable {
31
32 /** Serial version UID */
33 private static final long serialVersionUID = -6682656911025165584L;
34
35 /** The type to compare to */
36 private final Class<?> iType;
37
38 /**
39 * Factory to create the identity predicate.
40 *
41 * @param type the type to check for, may not be null
42 * @return the predicate
43 * @throws IllegalArgumentException if the class is null
44 */
45 public static Predicate<Object> instanceOfPredicate(final Class<?> type) {
46 if (type == null) {
47 throw new IllegalArgumentException("The type to check instanceof must not be null");
48 }
49 return new InstanceofPredicate(type);
50 }
51
52 /**
53 * Constructor that performs no validation.
54 * Use <code>getInstance</code> if you want that.
55 *
56 * @param type the type to check for
57 */
58 public InstanceofPredicate(final Class<?> type) {
59 super();
60 iType = type;
61 }
62
63 /**
64 * Evaluates the predicate returning true if the input object is of the correct type.
65 *
66 * @param object the input object
67 * @return true if input is of stored type
68 */
69 public boolean evaluate(final Object object) {
70 return iType.isInstance(object);
71 }
72
73 /**
74 * Gets the type to compare to.
75 *
76 * @return the type
77 * @since 3.1
78 */
79 public Class<?> getType() {
80 return iType;
81 }
82
83 }