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     *
063     * @param <K>  the key type
064     * @param <V>  the value type
065     * @param map  the map to decorate, must not be null
066     * @param keyTransformer  the transformer to use for key conversion, null means no transformation
067     * @param valueTransformer  the transformer to use for value conversion, null means no transformation
068     * @return a new transformed sorted map
069     * @throws NullPointerException if map is null
070     * @since 4.0
071     */
072    public static <K, V> TransformedSortedMap<K, V> transformedSortedMap(final SortedMap<K, V> map,
073            final Transformer<? super K, ? extends K> keyTransformer,
074            final Transformer<? super V, ? extends V> valueTransformer) {
075
076        final TransformedSortedMap<K, V> decorated =
077                new TransformedSortedMap<>(map, keyTransformer, valueTransformer);
078        if (!map.isEmpty()) {
079            final Map<K, V> transformed = decorated.transformMap(map);
080            decorated.clear();
081            decorated.decorated().putAll(transformed);  // avoids double transformation
082        }
083        return decorated;
084    }
085
086    /**
087     * Factory method to create a transforming sorted map.
088     * <p>
089     * If there are any elements already in the map being decorated, they are NOT transformed.
090     * Contrast this with {@link #transformedSortedMap(SortedMap, Transformer, Transformer)}.
091     *
092     * @param <K>  the key type
093     * @param <V>  the value type
094     * @param map  the map to decorate, must not be null
095     * @param keyTransformer  the predicate to validate the keys, null means no transformation
096     * @param valueTransformer  the predicate to validate to values, null means no transformation
097     * @return a new transformed sorted map
098     * @throws NullPointerException if the map is null
099     * @since 4.0
100     */
101    public static <K, V> TransformedSortedMap<K, V> transformingSortedMap(final SortedMap<K, V> map,
102            final Transformer<? super K, ? extends K> keyTransformer,
103            final Transformer<? super V, ? extends V> valueTransformer) {
104        return new TransformedSortedMap<>(map, keyTransformer, valueTransformer);
105    }
106
107    /**
108     * Constructor that wraps (not copies).
109     * <p>
110     * If there are any elements already in the collection being decorated, they
111     * are NOT transformed.</p>
112     *
113     * @param map  the map to decorate, must not be null
114     * @param keyTransformer  the predicate to validate the keys, null means no transformation
115     * @param valueTransformer  the predicate to validate to values, null means no transformation
116     * @throws NullPointerException if the map is null
117     */
118    protected TransformedSortedMap(final SortedMap<K, V> map,
119            final Transformer<? super K, ? extends K> keyTransformer,
120            final Transformer<? super V, ? extends V> valueTransformer) {
121        super(map, keyTransformer, valueTransformer);
122    }
123
124    @Override
125    public Comparator<? super K> comparator() {
126        return getSortedMap().comparator();
127    }
128
129    @Override
130    public K firstKey() {
131        return getSortedMap().firstKey();
132    }
133
134    /**
135     * Gets the map being decorated.
136     *
137     * @return the decorated map
138     */
139    protected SortedMap<K, V> getSortedMap() {
140        return (SortedMap<K, V>) map;
141    }
142
143    @Override
144    public SortedMap<K, V> headMap(final K toKey) {
145        final SortedMap<K, V> map = getSortedMap().headMap(toKey);
146        return new TransformedSortedMap<>(map, keyTransformer, valueTransformer);
147    }
148
149    @Override
150    public K lastKey() {
151        return getSortedMap().lastKey();
152    }
153
154    @Override
155    public SortedMap<K, V> subMap(final K fromKey, final K toKey) {
156        final SortedMap<K, V> map = getSortedMap().subMap(fromKey, 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}