    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 * </p>
    032 *
    033 * @param <E> the type of the elements in this set
    034 * @since 4.1
    035 */
    036public class TransformedNavigableSet<E> extends TransformedSortedSet<E> implements NavigableSet<E> {
    037
    038    /** Serialization version */
    039    private static final long serialVersionUID = 20150528L;
    040
    041    /**
    042     * Factory method to create a transforming navigable set.
    043     * <p>
    044     * If there are any elements already in the set being decorated, they
    045     * are NOT transformed.
    046     * Contrast this with {@link #transformedNavigableSet(NavigableSet, Transformer)}.
    047     *
    048     * @param <E> the element type
    049     * @param set  the set to decorate, must not be null
    050     * @param transformer  the transformer to use for conversion, must not be null
    051     * @return a new transformed {@link NavigableSet}
    052     * @throws NullPointerException if set or transformer is null
    053     */
    054    public static <E> TransformedNavigableSet<E> transformingNavigableSet(final NavigableSet<E> set,
    055            final Transformer<? super E, ? extends E> transformer) {
    056        return new TransformedNavigableSet<>(set, transformer);
    057    }
    058
    059    /**
    060     * Factory method to create a transforming navigable set that will transform
    061     * existing contents of the specified navigable set.
    062     * <p>
    063     * If there are any elements already in the set being decorated, they
    064     * will be transformed by this method.
    065     * Contrast this with {@link #transformingNavigableSet(NavigableSet, Transformer)}.
    066     *
    067     * @param <E> the element type
    068     * @param set  the set to decorate, must not be null
    069     * @param transformer  the transformer to use for conversion, must not be null
    070     * @return a new transformed {@link NavigableSet}
    071     * @throws NullPointerException if set or transformer is null
    072     */
    073    public static <E> TransformedNavigableSet<E> transformedNavigableSet(final NavigableSet<E> set,
    074            final Transformer<? super E, ? extends E> transformer) {
    075
    076        final TransformedNavigableSet<E> decorated = new TransformedNavigableSet<>(set, transformer);
    077        if (set.size() > 0) {
    078            @SuppressWarnings("unchecked") // set is type E
    079            final E[] values = (E[]) set.toArray(); // NOPMD - false positive for generics
    080            set.clear();
    081            for (final E value : values) {
    082                decorated.decorated().add(transformer.transform(value));
    083            }
    084        }
    085        return decorated;
    086    }
    087
    088    //-----------------------------------------------------------------------
    089    /**
    090     * Constructor that wraps (not copies).
    091     * <p>
    092     * If there are any elements already in the set being decorated, they
    093     * are NOT transformed.
    094     *
    095     * @param set  the set to decorate, must not be null
    096     * @param transformer  the transformer to use for conversion, must not be null
    097     * @throws NullPointerException if set or transformer is null
    098     */
    099    protected TransformedNavigableSet(final NavigableSet<E> set,
    100                                      final Transformer<? super E, ? extends E> transformer) {
    101        super(set, transformer);
    102    }
    103
    104    /**
    105     * Gets the decorated navigable set.
    106     *
    107     * @return the decorated navigable set
    108     */
    109    @Override
    110    protected NavigableSet<E> decorated() {
    111        return (NavigableSet<E>) super.decorated();
    112    }
    113
    114    //-----------------------------------------------------------------------
    115
    116    @Override
    117    public E lower(final E e) {
    118        return decorated().lower(e);
    119    }
    120
    121    @Override
    122    public E floor(final E e) {
    123        return decorated().floor(e);
    124    }
    125
    126    @Override
    127    public E ceiling(final E e) {
    128        return decorated().ceiling(e);
    129    }
    130
    131    @Override
    132    public E higher(final E e) {
    133        return decorated().higher(e);
    134    }
    135
    136    @Override
    137    public E pollFirst() {
    138        return decorated().pollFirst();
    139    }
    140
    141    @Override
    142    public E pollLast() {
    143        return decorated().pollLast();
    144    }
    145
    146    @Override
    147    public NavigableSet<E> descendingSet() {
    148        return transformingNavigableSet(decorated().descendingSet(), transformer);
    149    }
    150
    151    @Override
    152    public Iterator<E> descendingIterator() {
    153        return decorated().descendingIterator();
    154    }
    155
    156    @Override
    157    public NavigableSet<E> subSet(final E fromElement, final boolean fromInclusive, final E toElement,
    158            final boolean toInclusive) {
    159        final NavigableSet<E> sub = decorated().subSet(fromElement, fromInclusive, toElement, toInclusive);
    160        return transformingNavigableSet(sub, transformer);
    161    }
    162
    163    @Override
    164    public NavigableSet<E> headSet(final E toElement, final boolean inclusive) {
    165        final NavigableSet<E> head = decorated().headSet(toElement, inclusive);
    166        return transformingNavigableSet(head, transformer);
    167    }
    168
    169    @Override
    170    public NavigableSet<E> tailSet(final E fromElement, final boolean inclusive) {
    171        final NavigableSet<E> tail = decorated().tailSet(fromElement, inclusive);
    172        return transformingNavigableSet(tail, transformer);
    173    }
    174
    175}