001/* 002 * Copyright (C) 2007 The Guava Authors 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package com.google.common.collect; 018 019import static com.google.common.base.Preconditions.checkNotNull; 020 021import com.google.common.annotations.GwtCompatible; 022import com.google.common.annotations.GwtIncompatible; 023import java.io.IOException; 024import java.io.ObjectInputStream; 025import java.io.ObjectOutputStream; 026import java.util.Collection; 027import java.util.Comparator; 028import java.util.Map; 029import java.util.NavigableMap; 030import java.util.NavigableSet; 031import java.util.SortedSet; 032import java.util.TreeMap; 033import java.util.TreeSet; 034import org.checkerframework.checker.nullness.qual.Nullable; 035 036/** 037 * Implementation of {@code Multimap} whose keys and values are ordered by their natural ordering or 038 * by supplied comparators. In all cases, this implementation uses {@link Comparable#compareTo} or 039 * {@link Comparator#compare} instead of {@link Object#equals} to determine equivalence of 040 * instances. 041 * 042 * <p><b>Warning:</b> The comparators or comparables used must be <i>consistent with equals</i> as 043 * explained by the {@link Comparable} class specification. Otherwise, the resulting multiset will 044 * violate the general contract of {@link SetMultimap}, which it is specified in terms of {@link 045 * Object#equals}. 046 * 047 * <p>The collections returned by {@code keySet} and {@code asMap} iterate through the keys 048 * according to the key comparator ordering or the natural ordering of the keys. Similarly, {@code 049 * get}, {@code removeAll}, and {@code replaceValues} return collections that iterate through the 050 * values according to the value comparator ordering or the natural ordering of the values. The 051 * collections generated by {@code entries}, {@code keys}, and {@code values} iterate across the 052 * keys according to the above key ordering, and for each key they iterate across the values 053 * according to the value ordering. 054 * 055 * <p>The multimap does not store duplicate key-value pairs. Adding a new key-value pair equal to an 056 * existing key-value pair has no effect. 057 * 058 * <p>Null keys and values are permitted (provided, of course, that the respective comparators 059 * support them). All optional multimap methods are supported, and all returned views are 060 * modifiable. 061 * 062 * <p>This class is not threadsafe when any concurrent operations update the multimap. Concurrent 063 * read operations will work correctly. To allow concurrent update operations, wrap your multimap 064 * with a call to {@link Multimaps#synchronizedSortedSetMultimap}. 065 * 066 * <p>See the Guava User Guide article on <a href= 067 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#multimap"> {@code 068 * Multimap}</a>. 069 * 070 * @author Jared Levy 071 * @author Louis Wasserman 072 * @since 2.0 073 */ 074@GwtCompatible(serializable = true, emulated = true) 075public class TreeMultimap<K, V> extends AbstractSortedKeySortedSetMultimap<K, V> { 076 private transient Comparator<? super K> keyComparator; 077 private transient Comparator<? super V> valueComparator; 078 079 /** 080 * Creates an empty {@code TreeMultimap} ordered by the natural ordering of its keys and values. 081 */ 082 public static <K extends Comparable, V extends Comparable> TreeMultimap<K, V> create() { 083 return new TreeMultimap<>(Ordering.natural(), Ordering.natural()); 084 } 085 086 /** 087 * Creates an empty {@code TreeMultimap} instance using explicit comparators. Neither comparator 088 * may be null; use {@link Ordering#natural()} to specify natural order. 089 * 090 * @param keyComparator the comparator that determines the key ordering 091 * @param valueComparator the comparator that determines the value ordering 092 */ 093 public static <K, V> TreeMultimap<K, V> create( 094 Comparator<? super K> keyComparator, Comparator<? super V> valueComparator) { 095 return new TreeMultimap<>(checkNotNull(keyComparator), checkNotNull(valueComparator)); 096 } 097 098 /** 099 * Constructs a {@code TreeMultimap}, ordered by the natural ordering of its keys and values, with 100 * the same mappings as the specified multimap. 101 * 102 * @param multimap the multimap whose contents are copied to this multimap 103 */ 104 public static <K extends Comparable, V extends Comparable> TreeMultimap<K, V> create( 105 Multimap<? extends K, ? extends V> multimap) { 106 return new TreeMultimap<>(Ordering.natural(), Ordering.natural(), multimap); 107 } 108 109 TreeMultimap(Comparator<? super K> keyComparator, Comparator<? super V> valueComparator) { 110 super(new TreeMap<K, Collection<V>>(keyComparator)); 111 this.keyComparator = keyComparator; 112 this.valueComparator = valueComparator; 113 } 114 115 private TreeMultimap( 116 Comparator<? super K> keyComparator, 117 Comparator<? super V> valueComparator, 118 Multimap<? extends K, ? extends V> multimap) { 119 this(keyComparator, valueComparator); 120 putAll(multimap); 121 } 122 123 @Override 124 Map<K, Collection<V>> createAsMap() { 125 return createMaybeNavigableAsMap(); 126 } 127 128 /** 129 * {@inheritDoc} 130 * 131 * <p>Creates an empty {@code TreeSet} for a collection of values for one key. 132 * 133 * @return a new {@code TreeSet} containing a collection of values for one key 134 */ 135 @Override 136 SortedSet<V> createCollection() { 137 return new TreeSet<V>(valueComparator); 138 } 139 140 @Override 141 Collection<V> createCollection(@Nullable K key) { 142 if (key == null) { 143 keyComparator().compare(key, key); 144 } 145 return super.createCollection(key); 146 } 147 148 /** 149 * Returns the comparator that orders the multimap keys. 150 * 151 * @deprecated Use {@code ((NavigableSet<K>) multimap.keySet()).comparator()} instead. 152 */ 153 @Deprecated 154 public Comparator<? super K> keyComparator() { 155 return keyComparator; 156 } 157 158 @Override 159 public Comparator<? super V> valueComparator() { 160 return valueComparator; 161 } 162 163 /** @since 14.0 (present with return type {@code SortedSet} since 2.0) */ 164 @Override 165 @GwtIncompatible // NavigableSet 166 public NavigableSet<V> get(@Nullable K key) { 167 return (NavigableSet<V>) super.get(key); 168 } 169 170 /** 171 * {@inheritDoc} 172 * 173 * <p>Because a {@code TreeMultimap} has unique sorted keys, this method returns a {@link 174 * NavigableSet}, instead of the {@link java.util.Set} specified in the {@link Multimap} 175 * interface. 176 * 177 * @since 14.0 (present with return type {@code SortedSet} since 2.0) 178 */ 179 @Override 180 public NavigableSet<K> keySet() { 181 return (NavigableSet<K>) super.keySet(); 182 } 183 184 /** 185 * {@inheritDoc} 186 * 187 * <p>Because a {@code TreeMultimap} has unique sorted keys, this method returns a {@link 188 * NavigableMap}, instead of the {@link java.util.Map} specified in the {@link Multimap} 189 * interface. 190 * 191 * @since 14.0 (present with return type {@code SortedMap} since 2.0) 192 */ 193 @Override 194 public NavigableMap<K, Collection<V>> asMap() { 195 return (NavigableMap<K, Collection<V>>) super.asMap(); 196 } 197 198 /** 199 * @serialData key comparator, value comparator, number of distinct keys, and then for each 200 * distinct key: the key, number of values for that key, and key values 201 */ 202 @GwtIncompatible // java.io.ObjectOutputStream 203 private void writeObject(ObjectOutputStream stream) throws IOException { 204 stream.defaultWriteObject(); 205 stream.writeObject(keyComparator()); 206 stream.writeObject(valueComparator()); 207 Serialization.writeMultimap(this, stream); 208 } 209 210 @GwtIncompatible // java.io.ObjectInputStream 211 @SuppressWarnings("unchecked") // reading data stored by writeObject 212 private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException { 213 stream.defaultReadObject(); 214 keyComparator = checkNotNull((Comparator<? super K>) stream.readObject()); 215 valueComparator = checkNotNull((Comparator<? super V>) stream.readObject()); 216 setMap(new TreeMap<K, Collection<V>>(keyComparator)); 217 Serialization.populateMultimap(this, stream); 218 } 219 220 @GwtIncompatible // not needed in emulated source 221 private static final long serialVersionUID = 0; 222}