    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.Iterator;
    020import java.util.NavigableSet;
    021
    022import org.apache.commons.collections4.Transformer;
    023
    024/**
    025 * Decorates another <code>NavigableSet</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 *
    032 * @param <E> the type of the elements in this set
    033 * @since 4.1
    034 */
    035public class TransformedNavigableSet<E> extends TransformedSortedSet<E> implements NavigableSet<E> {
    036
    037    /** Serialization version */
    038    private static final long serialVersionUID = 20150528L;
    039
    040    /**
    041     * Factory method to create a transforming navigable set.
    042     * <p>
    043     * If there are any elements already in the set being decorated, they
    044     * are NOT transformed.
    045     * Contrast this with {@link #transformedNavigableSet(NavigableSet, Transformer)}.
    046     *
    047     * @param <E> the element type
    048     * @param set  the set to decorate, must not be null
    049     * @param transformer  the transformer to use for conversion, must not be null
    050     * @return a new transformed {@link NavigableSet}
    051     * @throws NullPointerException if set or transformer is null
    052     */
    053    public static <E> TransformedNavigableSet<E> transformingNavigableSet(final NavigableSet<E> set,
    054            final Transformer<? super E, ? extends E> transformer) {
    055        return new TransformedNavigableSet<>(set, transformer);
    056    }
    057
    058    /**
    059     * Factory method to create a transforming navigable set that will transform
    060     * existing contents of the specified navigable set.
    061     * <p>
    062     * If there are any elements already in the set being decorated, they
    063     * will be transformed by this method.
    064     * Contrast this with {@link #transformingNavigableSet(NavigableSet, Transformer)}.
    065     *
    066     * @param <E> the element type
    067     * @param set  the set to decorate, must not be null
    068     * @param transformer  the transformer to use for conversion, must not be null
    069     * @return a new transformed {@link NavigableSet}
    070     * @throws NullPointerException if set or transformer is null
    071     */
    072    public static <E> TransformedNavigableSet<E> transformedNavigableSet(final NavigableSet<E> set,
    073            final Transformer<? super E, ? extends E> transformer) {
    074
    075        final TransformedNavigableSet<E> decorated = new TransformedNavigableSet<>(set, transformer);
    076        if (set.size() > 0) {
    077            @SuppressWarnings("unchecked") // set is type E
    078            final E[] values = (E[]) set.toArray(); // NOPMD - false positive for generics
    079            set.clear();
    080            for (final E value : values) {
    081                decorated.decorated().add(transformer.transform(value));
    082            }
    083        }
    084        return decorated;
    085    }
    086
    087    //-----------------------------------------------------------------------
    088    /**
    089     * Constructor that wraps (not copies).
    090     * <p>
    091     * If there are any elements already in the set being decorated, they
    092     * are NOT transformed.
    093     *
    094     * @param set  the set to decorate, must not be null
    095     * @param transformer  the transformer to use for conversion, must not be null
    096     * @throws NullPointerException if set or transformer is null
    097     */
    098    protected TransformedNavigableSet(final NavigableSet<E> set,
    099                                      final Transformer<? super E, ? extends E> transformer) {
    100        super(set, transformer);
    101    }
    102
    103    /**
    104     * Gets the decorated navigable set.
    105     *
    106     * @return the decorated navigable set
    107     */
    108    @Override
    109    protected NavigableSet<E> decorated() {
    110        return (NavigableSet<E>) super.decorated();
    111    }
    112
    113    //-----------------------------------------------------------------------
    114
    115    @Override
    116    public E lower(final E e) {
    117        return decorated().lower(e);
    118    }
    119
    120    @Override
    121    public E floor(final E e) {
    122        return decorated().floor(e);
    123    }
    124
    125    @Override
    126    public E ceiling(final E e) {
    127        return decorated().ceiling(e);
    128    }
    129
    130    @Override
    131    public E higher(final E e) {
    132        return decorated().higher(e);
    133    }
    134
    135    @Override
    136    public E pollFirst() {
    137        return decorated().pollFirst();
    138    }
    139
    140    @Override
    141    public E pollLast() {
    142        return decorated().pollLast();
    143    }
    144
    145    @Override
    146    public NavigableSet<E> descendingSet() {
    147        return transformingNavigableSet(decorated().descendingSet(), transformer);
    148    }
    149
    150    @Override
    151    public Iterator<E> descendingIterator() {
    152        return decorated().descendingIterator();
    153    }
    154
    155    @Override
    156    public NavigableSet<E> subSet(final E fromElement, final boolean fromInclusive, final E toElement,
    157            final boolean toInclusive) {
    158        final NavigableSet<E> sub = decorated().subSet(fromElement, fromInclusive, toElement, toInclusive);
    159        return transformingNavigableSet(sub, transformer);
    160    }
    161
    162    @Override
    163    public NavigableSet<E> headSet(final E toElement, final boolean inclusive) {
    164        final NavigableSet<E> head = decorated().headSet(toElement, inclusive);
    165        return transformingNavigableSet(head, transformer);
    166    }
    167
    168    @Override
    169    public NavigableSet<E> tailSet(final E fromElement, final boolean inclusive) {
    170        final NavigableSet<E> tail = decorated().tailSet(fromElement, inclusive);
    171        return transformingNavigableSet(tail, transformer);
    172    }
    173
    174}