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 * @since 3.0 042 * @version $Id: TransformedSortedMap.html 972421 2015-11-14 20:00:04Z tn $ 043 */ 044public class TransformedSortedMap<K, V> 045 extends TransformedMap<K, V> 046 implements SortedMap<K, V> { 047 048 /** Serialization version */ 049 private static final long serialVersionUID = -8751771676410385778L; 050 051 /** 052 * Factory method to create a transforming sorted map. 053 * <p> 054 * If there are any elements already in the map being decorated, they are NOT transformed. 055 * Contrast this with {@link #transformedSortedMap(SortedMap, Transformer, Transformer)}. 056 * 057 * @param <K> the key type 058 * @param <V> the value type 059 * @param map the map to decorate, must not be null 060 * @param keyTransformer the predicate to validate the keys, null means no transformation 061 * @param valueTransformer the predicate to validate to values, null means no transformation 062 * @return a new transformed sorted map 063 * @throws IllegalArgumentException if the map is null 064 * @since 4.0 065 */ 066 public static <K, V> TransformedSortedMap<K, V> transformingSortedMap(final SortedMap<K, V> map, 067 final Transformer<? super K, ? extends K> keyTransformer, 068 final Transformer<? super V, ? extends V> valueTransformer) { 069 return new TransformedSortedMap<K, V>(map, keyTransformer, valueTransformer); 070 } 071 072 /** 073 * Factory method to create a transforming sorted map that will transform 074 * existing contents of the specified map. 075 * <p> 076 * If there are any elements already in the map being decorated, they 077 * will be transformed by this method. 078 * Contrast this with {@link #transformingSortedMap(SortedMap, Transformer, Transformer)}. 079 * 080 * @param <K> the key type 081 * @param <V> the value type 082 * @param map the map to decorate, must not be null 083 * @param keyTransformer the transformer to use for key conversion, null means no transformation 084 * @param valueTransformer the transformer to use for value conversion, null means no transformation 085 * @return a new transformed sorted map 086 * @throws IllegalArgumentException if map is null 087 * @since 4.0 088 */ 089 public static <K, V> TransformedSortedMap<K, V> transformedSortedMap(final SortedMap<K, V> map, 090 final Transformer<? super K, ? extends K> keyTransformer, 091 final Transformer<? super V, ? extends V> valueTransformer) { 092 093 final TransformedSortedMap<K, V> decorated = 094 new TransformedSortedMap<K, V>(map, keyTransformer, valueTransformer); 095 if (map.size() > 0) { 096 final Map<K, V> transformed = decorated.transformMap(map); 097 decorated.clear(); 098 decorated.decorated().putAll(transformed); // avoids double transformation 099 } 100 return decorated; 101 } 102 103 //----------------------------------------------------------------------- 104 /** 105 * Constructor that wraps (not copies). 106 * <p> 107 * If there are any elements already in the collection being decorated, they 108 * are NOT transformed.</p> 109 * 110 * @param map the map to decorate, must not be null 111 * @param keyTransformer the predicate to validate the keys, null means no transformation 112 * @param valueTransformer the predicate to validate to values, null means no transformation 113 * @throws IllegalArgumentException if the map is null 114 */ 115 protected TransformedSortedMap(final SortedMap<K, V> map, 116 final Transformer<? super K, ? extends K> keyTransformer, 117 final Transformer<? super V, ? extends V> valueTransformer) { 118 super(map, keyTransformer, valueTransformer); 119 } 120 121 //----------------------------------------------------------------------- 122 /** 123 * Gets the map being decorated. 124 * 125 * @return the decorated map 126 */ 127 protected SortedMap<K, V> getSortedMap() { 128 return (SortedMap<K, V>) map; 129 } 130 131 //----------------------------------------------------------------------- 132 public K firstKey() { 133 return getSortedMap().firstKey(); 134 } 135 136 public K lastKey() { 137 return getSortedMap().lastKey(); 138 } 139 140 public Comparator<? super K> comparator() { 141 return getSortedMap().comparator(); 142 } 143 144 public SortedMap<K, V> subMap(final K fromKey, final K toKey) { 145 final SortedMap<K, V> map = getSortedMap().subMap(fromKey, toKey); 146 return new TransformedSortedMap<K, V>(map, keyTransformer, valueTransformer); 147 } 148 149 public SortedMap<K, V> headMap(final K toKey) { 150 final SortedMap<K, V> map = getSortedMap().headMap(toKey); 151 return new TransformedSortedMap<K, V>(map, keyTransformer, valueTransformer); 152 } 153 154 public SortedMap<K, V> tailMap(final K fromKey) { 155 final SortedMap<K, V> map = getSortedMap().tailMap(fromKey); 156 return new TransformedSortedMap<K, V>(map, keyTransformer, valueTransformer); 157 } 158 159}