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.set;
18
19 import java.util.Set;
20
21 import org.apache.commons.collections.Predicate;
22 import org.apache.commons.collections.collection.PredicatedCollection;
23
24 /**
25 * Decorates another <code>Set</code> to validate that all additions
26 * match a specified predicate.
27 * <p>
28 * This set exists to provide validation for the decorated set.
29 * It is normally created to decorate an empty set.
30 * If an object cannot be added to the set, an IllegalArgumentException is thrown.
31 * <p>
32 * One usage would be to ensure that no null entries are added to the set.
33 * <pre>Set set = PredicatedSet.decorate(new HashSet(), NotNullPredicate.INSTANCE);</pre>
34 * <p>
35 * This class is Serializable from Commons Collections 3.1.
36 *
37 * @since 3.0
38 * @version $Id: PredicatedSet.java 1429905 2013-01-07 17:15:14Z ggregory $
39 */
40 public class PredicatedSet<E> extends PredicatedCollection<E> implements Set<E> {
41
42 /** Serialization version */
43 private static final long serialVersionUID = -684521469108685117L;
44
45 /**
46 * Factory method to create a predicated (validating) set.
47 * <p>
48 * If there are any elements already in the set being decorated, they
49 * are validated.
50 *
51 * @param <E> the element type
52 * @param set the set to decorate, must not be null
53 * @param predicate the predicate to use for validation, must not be null
54 * @return a decorated set
55 * @throws IllegalArgumentException if set or predicate is null
56 * @throws IllegalArgumentException if the set contains invalid elements
57 */
58 public static <E> PredicatedSet<E> predicatedSet(final Set<E> set, final Predicate<? super E> predicate) {
59 return new PredicatedSet<E>(set, predicate);
60 }
61
62 //-----------------------------------------------------------------------
63 /**
64 * Constructor that wraps (not copies).
65 * <p>
66 * If there are any elements already in the set being decorated, they
67 * are validated.
68 *
69 * @param set the set to decorate, must not be null
70 * @param predicate the predicate to use for validation, must not be null
71 * @throws IllegalArgumentException if set or predicate is null
72 * @throws IllegalArgumentException if the set contains invalid elements
73 */
74 protected PredicatedSet(final Set<E> set, final Predicate<? super E> predicate) {
75 super(set, predicate);
76 }
77
78 /**
79 * Gets the set being decorated.
80 *
81 * @return the decorated set
82 */
83 @Override
84 protected Set<E> decorated() {
85 return (Set<E>) super.decorated();
86 }
87
88 }