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 } 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 * <p>
034 * <strong>Note that TransformedSortedMap is not synchronized and is not thread-safe.</strong>
035 * If you wish to use this map from multiple threads concurrently, you must use
036 * appropriate synchronization. The simplest approach is to wrap this map
037 * using {@link java.util.Collections#synchronizedSortedMap}. This class may throw
038 * exceptions when accessed by concurrent threads without synchronization.
039 * </p>
040 * <p>
041 * This class is Serializable from Commons Collections 3.1.
042 * </p>
043 *
044 * @param <K> the type of the keys in this map
045 * @param <V> the type of the values in this map
046 * @since 3.0
047 */
048public class TransformedSortedMap<K, V>
049        extends TransformedMap<K, V>
050        implements SortedMap<K, V> {
051
052    /** Serialization version */
053    private static final long serialVersionUID = -8751771676410385778L;
054
055    /**
056     * Factory method to create a transforming sorted map that will transform
057     * existing contents of the specified map.
058     * <p>
059     * If there are any elements already in the map being decorated, they
060     * will be transformed by this method.
061     * Contrast this with {@link #transformingSortedMap(SortedMap, Transformer, Transformer)}.
062     * </p>
063     *
064     * @param <K>  the key type
065     * @param <V>  the value type
066     * @param map  the map to decorate, must not be null
067     * @param keyTransformer  the transformer to use for key conversion, null means no transformation
068     * @param valueTransformer  the transformer to use for value conversion, null means no transformation
069     * @return a new transformed sorted map
070     * @throws NullPointerException if map is null
071     * @since 4.0
072     */
073    public static <K, V> TransformedSortedMap<K, V> transformedSortedMap(final SortedMap<K, V> map,
074            final Transformer<? super K, ? extends K> keyTransformer,
075            final Transformer<? super V, ? extends V> valueTransformer) {
076
077        final TransformedSortedMap<K, V> decorated =
078                new TransformedSortedMap<>(map, keyTransformer, valueTransformer);
079        if (!map.isEmpty()) {
080            final Map<K, V> transformed = decorated.transformMap(map);
081            decorated.clear();
082            decorated.decorated().putAll(transformed);  // avoids double transformation
083        }
084        return decorated;
085    }
086
087    /**
088     * Factory method to create a transforming sorted map.
089     * <p>
090     * If there are any elements already in the map being decorated, they are NOT transformed.
091     * Contrast this with {@link #transformedSortedMap(SortedMap, Transformer, Transformer)}.
092     * </p>
093     *
094     * @param <K>  the key type
095     * @param <V>  the value type
096     * @param map  the map to decorate, must not be null
097     * @param keyTransformer  the predicate to validate the keys, null means no transformation
098     * @param valueTransformer  the predicate to validate to values, null means no transformation
099     * @return a new transformed sorted map
100     * @throws NullPointerException if the map is null
101     * @since 4.0
102     */
103    public static <K, V> TransformedSortedMap<K, V> transformingSortedMap(final SortedMap<K, V> map,
104            final Transformer<? super K, ? extends K> keyTransformer,
105            final Transformer<? super V, ? extends V> valueTransformer) {
106        return new TransformedSortedMap<>(map, keyTransformer, valueTransformer);
107    }
108
109    /**
110     * Constructor that wraps (not copies).
111     * <p>
112     * If there are any elements already in the collection being decorated, they
113     * are NOT transformed.
114     * </p>
115     *
116     * @param map  the map to decorate, must not be null
117     * @param keyTransformer  the predicate to validate the keys, null means no transformation
118     * @param valueTransformer  the predicate to validate to values, null means no transformation
119     * @throws NullPointerException if the map is null
120     */
121    protected TransformedSortedMap(final SortedMap<K, V> map,
122            final Transformer<? super K, ? extends K> keyTransformer,
123            final Transformer<? super V, ? extends V> valueTransformer) {
124        super(map, keyTransformer, valueTransformer);
125    }
126
127    @Override
128    public Comparator<? super K> comparator() {
129        return getSortedMap().comparator();
130    }
131
132    @Override
133    public K firstKey() {
134        return getSortedMap().firstKey();
135    }
136
137    /**
138     * Gets the map being decorated.
139     *
140     * @return the decorated map
141     */
142    protected SortedMap<K, V> getSortedMap() {
143        return (SortedMap<K, V>) map;
144    }
145
146    @Override
147    public SortedMap<K, V> headMap(final K toKey) {
148        final SortedMap<K, V> map = getSortedMap().headMap(toKey);
149        return new TransformedSortedMap<>(map, keyTransformer, valueTransformer);
150    }
151
152    @Override
153    public K lastKey() {
154        return getSortedMap().lastKey();
155    }
156
157    @Override
158    public SortedMap<K, V> subMap(final K fromKey, final K toKey) {
159        final SortedMap<K, V> map = getSortedMap().subMap(fromKey, toKey);
160        return new TransformedSortedMap<>(map, keyTransformer, valueTransformer);
161    }
162
163    @Override
164    public SortedMap<K, V> tailMap(final K fromKey) {
165        final SortedMap<K, V> map = getSortedMap().tailMap(fromKey);
166        return new TransformedSortedMap<>(map, keyTransformer, valueTransformer);
167    }
168
169}