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.bag;
18
19 import java.util.Set;
20
21 import org.apache.commons.collections4.Bag;
22 import org.apache.commons.collections4.Predicate;
23 import org.apache.commons.collections4.collection.PredicatedCollection;
24
25 /**
26 * Decorates another {@link Bag} to validate that additions
27 * match a specified predicate.
28 * <p>
29 * This bag exists to provide validation for the decorated bag.
30 * It is normally created to decorate an empty bag.
31 * If an object cannot be added to the bag, an {@link IllegalArgumentException} is thrown.
32 * </p>
33 * <p>
34 * One usage would be to ensure that no null entries are added to the bag.
35 * </p>
36 * <pre>
37 * Bag bag = PredicatedBag.predicatedBag(new HashBag(), NotNullPredicate.INSTANCE);
38 * </pre>
39 * <p>
40 * This class is Serializable from Commons Collections 3.1.
41 * </p>
42 *
43 * @param <E> the type of elements in this bag
44 * @since 3.0
45 */
46 public class PredicatedBag<E> extends PredicatedCollection<E> implements Bag<E> {
47
48 /** Serialization version */
49 private static final long serialVersionUID = -2575833140344736876L;
50
51 /**
52 * Factory method to create a predicated (validating) bag.
53 * <p>
54 * If there are any elements already in the bag being decorated, they
55 * are validated.
56 *
57 * @param <E> the type of the elements in the bag
58 * @param bag the bag to decorate, must not be null
59 * @param predicate the predicate to use for validation, must not be null
60 * @return a new predicated Bag
61 * @throws NullPointerException if bag or predicate is null
62 * @throws IllegalArgumentException if the bag contains invalid elements
63 * @since 4.0
64 */
65 public static <E> PredicatedBag<E> predicatedBag(final Bag<E> bag, final Predicate<? super E> predicate) {
66 return new PredicatedBag<>(bag, predicate);
67 }
68
69 /**
70 * Constructor that wraps (not copies).
71 * <p>
72 * If there are any elements already in the bag being decorated, they
73 * are validated.
74 *
75 * @param bag the bag to decorate, must not be null
76 * @param predicate the predicate to use for validation, must not be null
77 * @throws NullPointerException if bag or predicate is null
78 * @throws IllegalArgumentException if the bag contains invalid elements
79 */
80 protected PredicatedBag(final Bag<E> bag, final Predicate<? super E> predicate) {
81 super(bag, predicate);
82 }
83
84 @Override
85 public boolean add(final E object, final int count) {
86 validate(object);
87 return decorated().add(object, count);
88 }
89
90 /**
91 * Gets the decorated bag.
92 *
93 * @return the decorated bag
94 */
95 @Override
96 protected Bag<E> decorated() {
97 return (Bag<E>) super.decorated();
98 }
99
100 @Override
101 public boolean equals(final Object object) {
102 return object == this || decorated().equals(object);
103 }
104
105 @Override
106 public int getCount(final Object object) {
107 return decorated().getCount(object);
108 }
109
110 @Override
111 public int hashCode() {
112 return decorated().hashCode();
113 }
114
115 @Override
116 public boolean remove(final Object object, final int count) {
117 return decorated().remove(object, count);
118 }
119
120 @Override
121 public Set<E> uniqueSet() {
122 return decorated().uniqueSet();
123 }
124
125 }