    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}