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.Comparator;
20 import java.util.SortedSet;
21
22 import org.apache.commons.collections.Transformer;
23
24 /**
25 * Decorates another <code>SortedSet</code> to transform objects that are added.
26 * <p>
27 * The add methods are affected by this class.
28 * Thus objects must be removed or searched for using their transformed form.
29 * For example, if the transformation converts Strings to Integers, you must
30 * use the Integer form to remove objects.
31 * <p>
32 * This class is Serializable from Commons Collections 3.1.
33 *
34 * @since 3.0
35 * @version $Id: TransformedSortedSet.java 1451177 2013-02-28 11:42:31Z tn $
36 */
37 public class TransformedSortedSet<E> extends TransformedSet<E> implements SortedSet<E> {
38
39 /** Serialization version */
40 private static final long serialVersionUID = -1675486811351124386L;
41
42 /**
43 * Factory method to create a transforming sorted set.
44 * <p>
45 * If there are any elements already in the set being decorated, they
46 * are NOT transformed.
47 * Contrast this with {@link #transformedSortedSet(SortedSet, Transformer)}.
48 *
49 * @param <E> the element type
50 * @param set the set to decorate, must not be null
51 * @param transformer the transformer to use for conversion, must not be null
52 * @return a new transformed {@link SortedSet}
53 * @throws IllegalArgumentException if set or transformer is null
54 */
55 public static <E> TransformedSortedSet<E> transformingSortedSet(final SortedSet<E> set,
56 final Transformer<? super E, ? extends E> transformer) {
57 return new TransformedSortedSet<E>(set, transformer);
58 }
59
60 /**
61 * Factory method to create a transforming sorted set that will transform
62 * existing contents of the specified sorted set.
63 * <p>
64 * If there are any elements already in the set being decorated, they
65 * will be transformed by this method.
66 * Contrast this with {@link #transformingSortedSet(SortedSet, Transformer)}.
67 *
68 * @param <E> the element type
69 * @param set the set to decorate, must not be null
70 * @param transformer the transformer to use for conversion, must not be null
71 * @return a new transformed {@link SortedSet}
72 * @throws IllegalArgumentException if set or transformer is null
73 * @since 4.0
74 */
75 public static <E> TransformedSortedSet<E> transformedSortedSet(final SortedSet<E> set,
76 final Transformer<? super E, ? extends E> transformer) {
77
78 final TransformedSortedSet<E> decorated = new TransformedSortedSet<E>(set, transformer);
79 if (transformer != null && set != null && set.size() > 0) {
80 @SuppressWarnings("unchecked") // set is type E
81 final E[] values = (E[]) set.toArray();
82 set.clear();
83 for (final E value : values) {
84 decorated.decorated().add(transformer.transform(value));
85 }
86 }
87 return decorated;
88 }
89
90 //-----------------------------------------------------------------------
91 /**
92 * Constructor that wraps (not copies).
93 * <p>
94 * If there are any elements already in the set being decorated, they
95 * are NOT transformed.
96 *
97 * @param set the set to decorate, must not be null
98 * @param transformer the transformer to use for conversion, must not be null
99 * @throws IllegalArgumentException if set or transformer is null
100 */
101 protected TransformedSortedSet(final SortedSet<E> set, final Transformer<? super E, ? extends E> transformer) {
102 super(set, transformer);
103 }
104
105 /**
106 * Gets the decorated set.
107 *
108 * @return the decorated set
109 */
110 protected SortedSet<E> getSortedSet() {
111 return (SortedSet<E>) collection;
112 }
113
114 //-----------------------------------------------------------------------
115 public E first() {
116 return getSortedSet().first();
117 }
118
119 public E last() {
120 return getSortedSet().last();
121 }
122
123 public Comparator<? super E> comparator() {
124 return getSortedSet().comparator();
125 }
126
127 //-----------------------------------------------------------------------
128 public SortedSet<E> subSet(final E fromElement, final E toElement) {
129 final SortedSet<E> set = getSortedSet().subSet(fromElement, toElement);
130 return new TransformedSortedSet<E>(set, transformer);
131 }
132
133 public SortedSet<E> headSet(final E toElement) {
134 final SortedSet<E> set = getSortedSet().headSet(toElement);
135 return new TransformedSortedSet<E>(set, transformer);
136 }
137
138 public SortedSet<E> tailSet(final E fromElement) {
139 final SortedSet<E> set = getSortedSet().tailSet(fromElement);
140 return new TransformedSortedSet<E>(set, transformer);
141 }
142
143 }