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 * https://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.Transformer;
23 import org.apache.commons.collections4.collection.TransformedCollection;
24 import org.apache.commons.collections4.multiset.TransformedMultiSet;
25 import org.apache.commons.collections4.set.TransformedSet;
26
27 /**
28 * Decorates another {@link Bag} to transform objects that are added.
29 * <p>
30 * The add methods are affected by this class.
31 * Thus objects must be removed or searched for using their transformed form.
32 * For example, if the transformation converts Strings to Integers, you must
33 * use the Integer form to remove objects.
34 * </p>
35 * <p>
36 * This class is Serializable from Commons Collections 3.1.
37 * </p>
38 *
39 * @param <E> The type of elements in this bag
40 * @since 3.0
41 * @deprecated Since 4.6.0, use {@link TransformedMultiSet} instead.
42 */
43 @Deprecated
44 public class TransformedBag<E> extends TransformedCollection<E> implements Bag<E> {
45
46 /** Serialization version */
47 private static final long serialVersionUID = 5421170911299074185L;
48
49 /**
50 * Factory method to create a transforming bag that will transform
51 * existing contents of the specified bag.
52 * <p>
53 * If there are any elements already in the bag being decorated, they
54 * will be transformed by this method.
55 * Contrast this with {@link #transformingBag(Bag, Transformer)}.
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 transformer The transformer to use for conversion, must not be null
60 * @return A new transformed Bag
61 * @throws NullPointerException if bag or transformer is null
62 * @since 4.0
63 */
64 public static <E> Bag<E> transformedBag(final Bag<E> bag, final Transformer<? super E, ? extends E> transformer) {
65 final TransformedBag<E> decorated = new TransformedBag<>(bag, transformer);
66 if (!bag.isEmpty()) {
67 @SuppressWarnings("unchecked") // Bag is of type E
68 final E[] values = (E[]) bag.toArray(); // NOPMD - false positive for generics
69 bag.clear();
70 for (final E value : values) {
71 decorated.decorated().add(transformer.apply(value));
72 }
73 }
74 return decorated;
75 }
76
77 /**
78 * Factory method to create a transforming bag.
79 * <p>
80 * If there are any elements already in the bag being decorated, they
81 * are NOT transformed. Contrast this with {@link #transformedBag(Bag, Transformer)}.
82 *
83 * @param <E> The type of the elements in the bag
84 * @param bag The bag to decorate, must not be null
85 * @param transformer The transformer to use for conversion, must not be null
86 * @return A new transformed Bag
87 * @throws NullPointerException if bag or transformer is null
88 * @since 4.0
89 */
90 public static <E> Bag<E> transformingBag(final Bag<E> bag, final Transformer<? super E, ? extends E> transformer) {
91 return new TransformedBag<>(bag, transformer);
92 }
93
94 /**
95 * Constructor that wraps (not copies).
96 * <p>
97 * If there are any elements already in the bag being decorated, they
98 * are NOT transformed.
99 *
100 * @param bag The bag to decorate, must not be null
101 * @param transformer The transformer to use for conversion, must not be null
102 * @throws NullPointerException if bag or transformer is null
103 */
104 protected TransformedBag(final Bag<E> bag, final Transformer<? super E, ? extends E> transformer) {
105 super(bag, transformer);
106 }
107
108 @Override
109 public boolean add(final E object, final int nCopies) {
110 return getBag().add(transform(object), nCopies);
111 }
112
113 @Override
114 public boolean equals(final Object object) {
115 return object == this || decorated().equals(object);
116 }
117
118 /**
119 * Gets the decorated bag.
120 *
121 * @return The decorated bag
122 */
123 protected Bag<E> getBag() {
124 return (Bag<E>) decorated();
125 }
126
127 @Override
128 public int getCount(final Object object) {
129 return getBag().getCount(object);
130 }
131
132 @Override
133 public int hashCode() {
134 return decorated().hashCode();
135 }
136
137 @Override
138 public boolean remove(final Object object, final int nCopies) {
139 return getBag().remove(object, nCopies);
140 }
141
142 @Override
143 public Set<E> uniqueSet() {
144 final Set<E> set = getBag().uniqueSet();
145 return TransformedSet.<E>transformingSet(set, transformer);
146 }
147
148 }