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.multiset;
18
19 import java.util.Set;
20
21 import org.apache.commons.collections4.MultiSet;
22 import org.apache.commons.collections4.Predicate;
23 import org.apache.commons.collections4.collection.PredicatedCollection;
24
25 /**
26 * Decorates another {@link MultiSet} to validate that additions
27 * match a specified predicate.
28 * <p>
29 * This multiset exists to provide validation for the decorated multiset.
30 * It is normally created to decorate an empty multiset.
31 * If an object cannot be added to the multiset, an {@link IllegalArgumentException}
32 * is thrown.
33 * </p>
34 * <p>
35 * One usage would be to ensure that no null entries are added to the multiset.
36 * </p>
37 * <pre>
38 * MultiSet<E> set =
39 * PredicatedMultiSet.predicatedMultiSet(new HashMultiSet<E>(),
40 * NotNullPredicate.notNullPredicate());
41 * </pre>
42 *
43 * @param <E> the type held in the multiset
44 * @since 4.1
45 */
46 public class PredicatedMultiSet<E> extends PredicatedCollection<E> implements MultiSet<E> {
47
48 /** Serialization version */
49 private static final long serialVersionUID = 20150629L;
50
51 /**
52 * Factory method to create a predicated (validating) multiset.
53 * <p>
54 * If there are any elements already in the multiset being decorated, they
55 * are validated.
56 *
57 * @param <E> the type of the elements in the multiset
58 * @param multiset the multiset to decorate, must not be null
59 * @param predicate the predicate to use for validation, must not be null
60 * @return a new predicated MultiSet
61 * @throws NullPointerException if multiset or predicate is null
62 * @throws IllegalArgumentException if the multiset contains invalid elements
63 */
64 public static <E> PredicatedMultiSet<E> predicatedMultiSet(final MultiSet<E> multiset,
65 final Predicate<? super E> predicate) {
66 return new PredicatedMultiSet<>(multiset, predicate);
67 }
68
69 /**
70 * Constructor that wraps (not copies).
71 * <p>
72 * If there are any elements already in the multiset being decorated, they
73 * are validated.
74 * </p>
75 *
76 * @param multiset the multiset to decorate, must not be null
77 * @param predicate the predicate to use for validation, must not be null
78 * @throws NullPointerException if multiset or predicate is null
79 * @throws IllegalArgumentException if the multiset contains invalid elements
80 */
81 protected PredicatedMultiSet(final MultiSet<E> multiset, final Predicate<? super E> predicate) {
82 super(multiset, predicate);
83 }
84
85 @Override
86 public int add(final E object, final int count) {
87 validate(object);
88 return decorated().add(object, count);
89 }
90
91 /**
92 * Gets the decorated multiset.
93 *
94 * @return the decorated multiset
95 */
96 @Override
97 protected MultiSet<E> decorated() {
98 return (MultiSet<E>) super.decorated();
99 }
100
101 @Override
102 public Set<MultiSet.Entry<E>> entrySet() {
103 return decorated().entrySet();
104 }
105
106 @Override
107 public boolean equals(final Object object) {
108 return object == this || decorated().equals(object);
109 }
110
111 @Override
112 public int getCount(final Object object) {
113 return decorated().getCount(object);
114 }
115
116 @Override
117 public int hashCode() {
118 return decorated().hashCode();
119 }
120
121 @Override
122 public int remove(final Object object, final int count) {
123 return decorated().remove(object, count);
124 }
125
126 @Override
127 public int setCount(final E object, final int count) {
128 validate(object);
129 return decorated().setCount(object, count);
130 }
131
132 @Override
133 public Set<E> uniqueSet() {
134 return decorated().uniqueSet();
135 }
136
137 }