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}