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 * <strong>Note that TransformedSortedMap is not synchronized and is not thread-safe.</strong> 034 * If you wish to use this map from multiple threads concurrently, you must use 035 * appropriate synchronization. The simplest approach is to wrap this map 036 * using {@link java.util.Collections#synchronizedSortedMap}. This class may throw 037 * exceptions when accessed by concurrent threads without synchronization. 038 * <p> 039 * This class is Serializable from Commons Collections 3.1. 040 * 041 * @param <K> the type of the keys in this map 042 * @param <V> the type of the values in this map 043 * @since 3.0 044 */ 045public class TransformedSortedMap<K, V> 046 extends TransformedMap<K, V> 047 implements SortedMap<K, V> { 048 049 /** Serialization version */ 050 private static final long serialVersionUID = -8751771676410385778L; 051 052 /** 053 * Factory method to create a transforming sorted map. 054 * <p> 055 * If there are any elements already in the map being decorated, they are NOT transformed. 056 * Contrast this with {@link #transformedSortedMap(SortedMap, Transformer, Transformer)}. 057 * 058 * @param <K> the key type 059 * @param <V> the value type 060 * @param map the map to decorate, must not be null 061 * @param keyTransformer the predicate to validate the keys, null means no transformation 062 * @param valueTransformer the predicate to validate to values, null means no transformation 063 * @return a new transformed sorted map 064 * @throws NullPointerException if the map is null 065 * @since 4.0 066 */ 067 public static <K, V> TransformedSortedMap<K, V> transformingSortedMap(final SortedMap<K, V> map, 068 final Transformer<? super K, ? extends K> keyTransformer, 069 final Transformer<? super V, ? extends V> valueTransformer) { 070 return new TransformedSortedMap<>(map, keyTransformer, valueTransformer); 071 } 072 073 /** 074 * Factory method to create a transforming sorted map that will transform 075 * existing contents of the specified map. 076 * <p> 077 * If there are any elements already in the map being decorated, they 078 * will be transformed by this method. 079 * Contrast this with {@link #transformingSortedMap(SortedMap, Transformer, Transformer)}. 080 * 081 * @param <K> the key type 082 * @param <V> the value type 083 * @param map the map to decorate, must not be null 084 * @param keyTransformer the transformer to use for key conversion, null means no transformation 085 * @param valueTransformer the transformer to use for value conversion, null means no transformation 086 * @return a new transformed sorted map 087 * @throws NullPointerException if map is null 088 * @since 4.0 089 */ 090 public static <K, V> TransformedSortedMap<K, V> transformedSortedMap(final SortedMap<K, V> map, 091 final Transformer<? super K, ? extends K> keyTransformer, 092 final Transformer<? super V, ? extends V> valueTransformer) { 093 094 final TransformedSortedMap<K, V> decorated = 095 new TransformedSortedMap<>(map, keyTransformer, valueTransformer); 096 if (map.size() > 0) { 097 final Map<K, V> transformed = decorated.transformMap(map); 098 decorated.clear(); 099 decorated.decorated().putAll(transformed); // avoids double transformation 100 } 101 return decorated; 102 } 103 104 //----------------------------------------------------------------------- 105 /** 106 * Constructor that wraps (not copies). 107 * <p> 108 * If there are any elements already in the collection being decorated, they 109 * are NOT transformed.</p> 110 * 111 * @param map the map to decorate, must not be null 112 * @param keyTransformer the predicate to validate the keys, null means no transformation 113 * @param valueTransformer the predicate to validate to values, null means no transformation 114 * @throws NullPointerException if the map is null 115 */ 116 protected TransformedSortedMap(final SortedMap<K, V> map, 117 final Transformer<? super K, ? extends K> keyTransformer, 118 final Transformer<? super V, ? extends V> valueTransformer) { 119 super(map, keyTransformer, valueTransformer); 120 } 121 122 //----------------------------------------------------------------------- 123 /** 124 * Gets the map being decorated. 125 * 126 * @return the decorated map 127 */ 128 protected SortedMap<K, V> getSortedMap() { 129 return (SortedMap<K, V>) map; 130 } 131 132 //----------------------------------------------------------------------- 133 @Override 134 public K firstKey() { 135 return getSortedMap().firstKey(); 136 } 137 138 @Override 139 public K lastKey() { 140 return getSortedMap().lastKey(); 141 } 142 143 @Override 144 public Comparator<? super K> comparator() { 145 return getSortedMap().comparator(); 146 } 147 148 @Override 149 public SortedMap<K, V> subMap(final K fromKey, final K toKey) { 150 final SortedMap<K, V> map = getSortedMap().subMap(fromKey, toKey); 151 return new TransformedSortedMap<>(map, keyTransformer, valueTransformer); 152 } 153 154 @Override 155 public SortedMap<K, V> headMap(final K toKey) { 156 final SortedMap<K, V> map = getSortedMap().headMap(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}