001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.collections4.set;
018
019import java.util.Comparator;
020import java.util.SortedSet;
021
022import org.apache.commons.collections4.Transformer;
023
024/**
025 * Decorates another {@code SortedSet} to transform objects that are added.
026 * <p>
027 * The add methods are affected by this class.
028 * Thus objects must be removed or searched for using their transformed form.
029 * For example, if the transformation converts Strings to Integers, you must
030 * use the Integer form to remove objects.
031 * </p>
032 * <p>
033 * This class is Serializable from Commons Collections 3.1.
034 * </p>
035 *
036 * @param <E> the type of the elements in this set
037 * @since 3.0
038 */
039public class TransformedSortedSet<E> extends TransformedSet<E> implements SortedSet<E> {
040
041    /** Serialization version */
042    private static final long serialVersionUID = -1675486811351124386L;
043
044    /**
045     * Factory method to create a transforming sorted set that will transform
046     * existing contents of the specified sorted set.
047     * <p>
048     * If there are any elements already in the set being decorated, they
049     * will be transformed by this method.
050     * Contrast this with {@link #transformingSortedSet(SortedSet, Transformer)}.
051     *
052     * @param <E> the element type
053     * @param set  the set to decorate, must not be null
054     * @param transformer  the transformer to use for conversion, must not be null
055     * @return a new transformed {@link SortedSet}
056     * @throws NullPointerException if set or transformer is null
057     * @since 4.0
058     */
059    public static <E> TransformedSortedSet<E> transformedSortedSet(final SortedSet<E> set,
060            final Transformer<? super E, ? extends E> transformer) {
061
062        final TransformedSortedSet<E> decorated = new TransformedSortedSet<>(set, transformer);
063        if (!set.isEmpty()) {
064            @SuppressWarnings("unchecked") // set is type E
065            final E[] values = (E[]) set.toArray(); // NOPMD - false positive for generics
066            set.clear();
067            for (final E value : values) {
068                decorated.decorated().add(transformer.transform(value));
069            }
070        }
071        return decorated;
072    }
073
074    /**
075     * Factory method to create a transforming sorted set.
076     * <p>
077     * If there are any elements already in the set being decorated, they
078     * are NOT transformed.
079     * Contrast this with {@link #transformedSortedSet(SortedSet, Transformer)}.
080     *
081     * @param <E> the element type
082     * @param set  the set to decorate, must not be null
083     * @param transformer  the transformer to use for conversion, must not be null
084     * @return a new transformed {@link SortedSet}
085     * @throws NullPointerException if set or transformer is null
086     * @since 4.0
087     */
088    public static <E> TransformedSortedSet<E> transformingSortedSet(final SortedSet<E> set,
089            final Transformer<? super E, ? extends E> transformer) {
090        return new TransformedSortedSet<>(set, transformer);
091    }
092
093    /**
094     * Constructor that wraps (not copies).
095     * <p>
096     * If there are any elements already in the set being decorated, they
097     * are NOT transformed.
098     *
099     * @param set  the set to decorate, must not be null
100     * @param transformer  the transformer to use for conversion, must not be null
101     * @throws NullPointerException if set or transformer is null
102     */
103    protected TransformedSortedSet(final SortedSet<E> set, final Transformer<? super E, ? extends E> transformer) {
104        super(set, transformer);
105    }
106
107    @Override
108    public Comparator<? super E> comparator() {
109        return getSortedSet().comparator();
110    }
111
112    @Override
113    public E first() {
114        return getSortedSet().first();
115    }
116
117    /**
118     * Gets the decorated set.
119     *
120     * @return the decorated set
121     */
122    protected SortedSet<E> getSortedSet() {
123        return (SortedSet<E>) decorated();
124    }
125
126    @Override
127    public SortedSet<E> headSet(final E toElement) {
128        final SortedSet<E> set = getSortedSet().headSet(toElement);
129        return new TransformedSortedSet<>(set, transformer);
130    }
131
132    @Override
133    public E last() {
134        return getSortedSet().last();
135    }
136
137    @Override
138    public SortedSet<E> subSet(final E fromElement, final E toElement) {
139        final SortedSet<E> set = getSortedSet().subSet(fromElement, toElement);
140        return new TransformedSortedSet<>(set, transformer);
141    }
142
143    @Override
144    public SortedSet<E> tailSet(final E fromElement) {
145        final SortedSet<E> set = getSortedSet().tailSet(fromElement);
146        return new TransformedSortedSet<>(set, transformer);
147    }
148
149}