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</code> 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.
046     * <p>
047     * If there are any elements already in the set being decorated, they
048     * are NOT transformed.
049     * Contrast this with {@link #transformedSortedSet(SortedSet, Transformer)}.
050     *
051     * @param <E> the element type
052     * @param set  the set to decorate, must not be null
053     * @param transformer  the transformer to use for conversion, must not be null
054     * @return a new transformed {@link SortedSet}
055     * @throws NullPointerException if set or transformer is null
056     * @since 4.0
057     */
058    public static <E> TransformedSortedSet<E> transformingSortedSet(final SortedSet<E> set,
059            final Transformer<? super E, ? extends E> transformer) {
060        return new TransformedSortedSet<>(set, transformer);
061    }
062
063    /**
064     * Factory method to create a transforming sorted set that will transform
065     * existing contents of the specified sorted set.
066     * <p>
067     * If there are any elements already in the set being decorated, they
068     * will be transformed by this method.
069     * Contrast this with {@link #transformingSortedSet(SortedSet, Transformer)}.
070     *
071     * @param <E> the element type
072     * @param set  the set to decorate, must not be null
073     * @param transformer  the transformer to use for conversion, must not be null
074     * @return a new transformed {@link SortedSet}
075     * @throws NullPointerException if set or transformer is null
076     * @since 4.0
077     */
078    public static <E> TransformedSortedSet<E> transformedSortedSet(final SortedSet<E> set,
079            final Transformer<? super E, ? extends E> transformer) {
080
081        final TransformedSortedSet<E> decorated = new TransformedSortedSet<>(set, transformer);
082        if (set.size() > 0) {
083            @SuppressWarnings("unchecked") // set is type E
084            final E[] values = (E[]) set.toArray(); // NOPMD - false positive for generics
085            set.clear();
086            for (final E value : values) {
087                decorated.decorated().add(transformer.transform(value));
088            }
089        }
090        return decorated;
091    }
092
093    //-----------------------------------------------------------------------
094    /**
095     * Constructor that wraps (not copies).
096     * <p>
097     * If there are any elements already in the set being decorated, they
098     * are NOT transformed.
099     *
100     * @param set  the set to decorate, must not be null
101     * @param transformer  the transformer to use for conversion, must not be null
102     * @throws NullPointerException if set or transformer is null
103     */
104    protected TransformedSortedSet(final SortedSet<E> set, final Transformer<? super E, ? extends E> transformer) {
105        super(set, transformer);
106    }
107
108    /**
109     * Gets the decorated set.
110     *
111     * @return the decorated set
112     */
113    protected SortedSet<E> getSortedSet() {
114        return (SortedSet<E>) decorated();
115    }
116
117    //-----------------------------------------------------------------------
118    @Override
119    public E first() {
120        return getSortedSet().first();
121    }
122
123    @Override
124    public E last() {
125        return getSortedSet().last();
126    }
127
128    @Override
129    public Comparator<? super E> comparator() {
130        return getSortedSet().comparator();
131    }
132
133    //-----------------------------------------------------------------------
134    @Override
135    public SortedSet<E> subSet(final E fromElement, final E toElement) {
136        final SortedSet<E> set = getSortedSet().subSet(fromElement, toElement);
137        return new TransformedSortedSet<>(set, transformer);
138    }
139
140    @Override
141    public SortedSet<E> headSet(final E toElement) {
142        final SortedSet<E> set = getSortedSet().headSet(toElement);
143        return new TransformedSortedSet<>(set, transformer);
144    }
145
146    @Override
147    public SortedSet<E> tailSet(final E fromElement) {
148        final SortedSet<E> set = getSortedSet().tailSet(fromElement);
149        return new TransformedSortedSet<>(set, transformer);
150    }
151
152}