    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.map;
    018
    019import java.util.Comparator;
    020import java.util.Map;
    021import java.util.SortedMap;
    022
    023import org.apache.commons.collections4.Transformer;
    024
    025/**
    026 * Decorates another <code>SortedMap </code> to transform objects that are added.
    027 * <p>
    028 * The Map put methods and Map.Entry setValue method are affected by this class.
    029 * Thus objects must be removed or searched for using their transformed form.
    030 * For example, if the transformation converts Strings to Integers, you must
    031 * use the Integer form to remove objects.
    032 * <p>
    033 * <strong>Note that TransformedSortedMap is not synchronized and is not thread-safe.</strong>
    034 * If you wish to use this map from multiple threads concurrently, you must use
    035 * appropriate synchronization. The simplest approach is to wrap this map
    036 * using {@link java.util.Collections#synchronizedSortedMap}. This class may throw
    037 * exceptions when accessed by concurrent threads without synchronization.
    038 * <p>
    039 * This class is Serializable from Commons Collections 3.1.
    040 *
    041 * @param <K> the type of the keys in this map
    042 * @param <V> the type of the values in this map
    043 * @since 3.0
    044 */
    045public class TransformedSortedMap<K, V>
    046        extends TransformedMap<K, V>
    047        implements SortedMap<K, V> {
    048
    049    /** Serialization version */
    050    private static final long serialVersionUID = -8751771676410385778L;
    051
    052    /**
    053     * Factory method to create a transforming sorted map.
    054     * <p>
    055     * If there are any elements already in the map being decorated, they are NOT transformed.
    056     * Contrast this with {@link #transformedSortedMap(SortedMap, Transformer, Transformer)}.
    057     *
    058     * @param <K>  the key type
    059     * @param <V>  the value type
    060     * @param map  the map to decorate, must not be null
    061     * @param keyTransformer  the predicate to validate the keys, null means no transformation
    062     * @param valueTransformer  the predicate to validate to values, null means no transformation
    063     * @return a new transformed sorted map
    064     * @throws NullPointerException if the map is null
    065     * @since 4.0
    066     */
    067    public static <K, V> TransformedSortedMap<K, V> transformingSortedMap(final SortedMap<K, V> map,
    068            final Transformer<? super K, ? extends K> keyTransformer,
    069            final Transformer<? super V, ? extends V> valueTransformer) {
    070        return new TransformedSortedMap<>(map, keyTransformer, valueTransformer);
    071    }
    072
    073    /**
    074     * Factory method to create a transforming sorted map that will transform
    075     * existing contents of the specified map.
    076     * <p>
    077     * If there are any elements already in the map being decorated, they
    078     * will be transformed by this method.
    079     * Contrast this with {@link #transformingSortedMap(SortedMap, Transformer, Transformer)}.
    080     *
    081     * @param <K>  the key type
    082     * @param <V>  the value type
    083     * @param map  the map to decorate, must not be null
    084     * @param keyTransformer  the transformer to use for key conversion, null means no transformation
    085     * @param valueTransformer  the transformer to use for value conversion, null means no transformation
    086     * @return a new transformed sorted map
    087     * @throws NullPointerException if map is null
    088     * @since 4.0
    089     */
    090    public static <K, V> TransformedSortedMap<K, V> transformedSortedMap(final SortedMap<K, V> map,
    091            final Transformer<? super K, ? extends K> keyTransformer,
    092            final Transformer<? super V, ? extends V> valueTransformer) {
    093
    094        final TransformedSortedMap<K, V> decorated =
    095                new TransformedSortedMap<>(map, keyTransformer, valueTransformer);
    096        if (map.size() > 0) {
    097            final Map<K, V> transformed = decorated.transformMap(map);
    098            decorated.clear();
    099            decorated.decorated().putAll(transformed);  // avoids double transformation
    100        }
    101        return decorated;
    102    }
    103
    104    //-----------------------------------------------------------------------
    105    /**
    106     * Constructor that wraps (not copies).
    107     * <p>
    108     * If there are any elements already in the collection being decorated, they
    109     * are NOT transformed.</p>
    110     *
    111     * @param map  the map to decorate, must not be null
    112     * @param keyTransformer  the predicate to validate the keys, null means no transformation
    113     * @param valueTransformer  the predicate to validate to values, null means no transformation
    114     * @throws NullPointerException if the map is null
    115     */
    116    protected TransformedSortedMap(final SortedMap<K, V> map,
    117            final Transformer<? super K, ? extends K> keyTransformer,
    118            final Transformer<? super V, ? extends V> valueTransformer) {
    119        super(map, keyTransformer, valueTransformer);
    120    }
    121
    122    //-----------------------------------------------------------------------
    123    /**
    124     * Gets the map being decorated.
    125     *
    126     * @return the decorated map
    127     */
    128    protected SortedMap<K, V> getSortedMap() {
    129        return (SortedMap<K, V>) map;
    130    }
    131
    132    //-----------------------------------------------------------------------
    133    @Override
    134    public K firstKey() {
    135        return getSortedMap().firstKey();
    136    }
    137
    138    @Override
    139    public K lastKey() {
    140        return getSortedMap().lastKey();
    141    }
    142
    143    @Override
    144    public Comparator<? super K> comparator() {
    145        return getSortedMap().comparator();
    146    }
    147
    148    @Override
    149    public SortedMap<K, V> subMap(final K fromKey, final K toKey) {
    150        final SortedMap<K, V> map = getSortedMap().subMap(fromKey, toKey);
    151        return new TransformedSortedMap<>(map, keyTransformer, valueTransformer);
    152    }
    153
    154    @Override
    155    public SortedMap<K, V> headMap(final K toKey) {
    156        final SortedMap<K, V> map = getSortedMap().headMap(toKey);
    157        return new TransformedSortedMap<>(map, keyTransformer, valueTransformer);
    158    }
    159
    160    @Override
    161    public SortedMap<K, V> tailMap(final K fromKey) {
    162        final SortedMap<K, V> map = getSortedMap().tailMap(fromKey);
    163        return new TransformedSortedMap<>(map, keyTransformer, valueTransformer);
    164    }
    165
    166}