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 * <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. 057 * <p> 058 * If there are any elements already in the map being decorated, they are NOT transformed. 059 * Contrast this with {@link #transformedSortedMap(SortedMap, Transformer, Transformer)}. 060 * 061 * @param <K> the key type 062 * @param <V> the value type 063 * @param map the map to decorate, must not be null 064 * @param keyTransformer the predicate to validate the keys, null means no transformation 065 * @param valueTransformer the predicate to validate to values, null means no transformation 066 * @return a new transformed sorted map 067 * @throws NullPointerException if the map is null 068 * @since 4.0 069 */ 070 public static <K, V> TransformedSortedMap<K, V> transformingSortedMap(final SortedMap<K, V> map, 071 final Transformer<? super K, ? extends K> keyTransformer, 072 final Transformer<? super V, ? extends V> valueTransformer) { 073 return new TransformedSortedMap<>(map, keyTransformer, valueTransformer); 074 } 075 076 /** 077 * Factory method to create a transforming sorted map that will transform 078 * existing contents of the specified map. 079 * <p> 080 * If there are any elements already in the map being decorated, they 081 * will be transformed by this method. 082 * Contrast this with {@link #transformingSortedMap(SortedMap, Transformer, Transformer)}. 083 * 084 * @param <K> the key type 085 * @param <V> the value type 086 * @param map the map to decorate, must not be null 087 * @param keyTransformer the transformer to use for key conversion, null means no transformation 088 * @param valueTransformer the transformer to use for value conversion, null means no transformation 089 * @return a new transformed sorted map 090 * @throws NullPointerException if map is null 091 * @since 4.0 092 */ 093 public static <K, V> TransformedSortedMap<K, V> transformedSortedMap(final SortedMap<K, V> map, 094 final Transformer<? super K, ? extends K> keyTransformer, 095 final Transformer<? super V, ? extends V> valueTransformer) { 096 097 final TransformedSortedMap<K, V> decorated = 098 new TransformedSortedMap<>(map, keyTransformer, valueTransformer); 099 if (map.size() > 0) { 100 final Map<K, V> transformed = decorated.transformMap(map); 101 decorated.clear(); 102 decorated.decorated().putAll(transformed); // avoids double transformation 103 } 104 return decorated; 105 } 106 107 //----------------------------------------------------------------------- 108 /** 109 * Constructor that wraps (not copies). 110 * <p> 111 * If there are any elements already in the collection being decorated, they 112 * are NOT transformed.</p> 113 * 114 * @param map the map to decorate, must not be null 115 * @param keyTransformer the predicate to validate the keys, null means no transformation 116 * @param valueTransformer the predicate to validate to values, null means no transformation 117 * @throws NullPointerException if the map is null 118 */ 119 protected TransformedSortedMap(final SortedMap<K, V> map, 120 final Transformer<? super K, ? extends K> keyTransformer, 121 final Transformer<? super V, ? extends V> valueTransformer) { 122 super(map, keyTransformer, valueTransformer); 123 } 124 125 //----------------------------------------------------------------------- 126 /** 127 * Gets the map being decorated. 128 * 129 * @return the decorated map 130 */ 131 protected SortedMap<K, V> getSortedMap() { 132 return (SortedMap<K, V>) map; 133 } 134 135 //----------------------------------------------------------------------- 136 @Override 137 public K firstKey() { 138 return getSortedMap().firstKey(); 139 } 140 141 @Override 142 public K lastKey() { 143 return getSortedMap().lastKey(); 144 } 145 146 @Override 147 public Comparator<? super K> comparator() { 148 return getSortedMap().comparator(); 149 } 150 151 @Override 152 public SortedMap<K, V> subMap(final K fromKey, final K toKey) { 153 final SortedMap<K, V> map = getSortedMap().subMap(fromKey, toKey); 154 return new TransformedSortedMap<>(map, keyTransformer, valueTransformer); 155 } 156 157 @Override 158 public SortedMap<K, V> headMap(final K toKey) { 159 final SortedMap<K, V> map = getSortedMap().headMap(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}