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}