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 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 Multimap}</a>. 068 * 069 * @author Jared Levy 070 * @author Louis Wasserman 071 * @since 2.0 072 */ 073@GwtCompatible(serializable = true, emulated = true) 074@ElementTypesAreNonnullByDefault 075public class TreeMultimap<K extends @Nullable Object, V extends @Nullable Object> 076 extends AbstractSortedKeySortedSetMultimap<K, V> { 077 private transient Comparator<? super K> keyComparator; 078 private transient Comparator<? super V> valueComparator; 079 080 /** 081 * Creates an empty {@code TreeMultimap} ordered by the natural ordering of its keys and values. 082 */ 083 public static <K extends Comparable, V extends Comparable> TreeMultimap<K, V> create() { 084 return new TreeMultimap<>(Ordering.natural(), Ordering.natural()); 085 } 086 087 /** 088 * Creates an empty {@code TreeMultimap} instance using explicit comparators. Neither comparator 089 * may be null; use {@link Ordering#natural()} to specify natural order. 090 * 091 * @param keyComparator the comparator that determines the key ordering 092 * @param valueComparator the comparator that determines the value ordering 093 */ 094 public static <K extends @Nullable Object, V extends @Nullable Object> TreeMultimap<K, V> create( 095 Comparator<? super K> keyComparator, Comparator<? super V> valueComparator) { 096 return new TreeMultimap<>(checkNotNull(keyComparator), checkNotNull(valueComparator)); 097 } 098 099 /** 100 * Constructs a {@code TreeMultimap}, ordered by the natural ordering of its keys and values, with 101 * the same mappings as the specified multimap. 102 * 103 * @param multimap the multimap whose contents are copied to this multimap 104 */ 105 public static <K extends Comparable, V extends Comparable> TreeMultimap<K, V> create( 106 Multimap<? extends K, ? extends V> multimap) { 107 return new TreeMultimap<>(Ordering.natural(), Ordering.natural(), multimap); 108 } 109 110 TreeMultimap(Comparator<? super K> keyComparator, Comparator<? super V> valueComparator) { 111 super(new TreeMap<K, Collection<V>>(keyComparator)); 112 this.keyComparator = keyComparator; 113 this.valueComparator = valueComparator; 114 } 115 116 private TreeMultimap( 117 Comparator<? super K> keyComparator, 118 Comparator<? super V> valueComparator, 119 Multimap<? extends K, ? extends V> multimap) { 120 this(keyComparator, valueComparator); 121 putAll(multimap); 122 } 123 124 @Override 125 Map<K, Collection<V>> createAsMap() { 126 return createMaybeNavigableAsMap(); 127 } 128 129 /** 130 * {@inheritDoc} 131 * 132 * <p>Creates an empty {@code TreeSet} for a collection of values for one key. 133 * 134 * @return a new {@code TreeSet} containing a collection of values for one key 135 */ 136 @Override 137 SortedSet<V> createCollection() { 138 return new TreeSet<>(valueComparator); 139 } 140 141 @Override 142 Collection<V> createCollection(@ParametricNullness K key) { 143 if (key == null) { 144 keyComparator().compare(key, key); 145 } 146 return super.createCollection(key); 147 } 148 149 /** 150 * Returns the comparator that orders the multimap keys. 151 * 152 * @deprecated Use {@code ((NavigableSet<K>) multimap.keySet()).comparator()} instead. 153 */ 154 @Deprecated 155 public Comparator<? super K> keyComparator() { 156 return keyComparator; 157 } 158 159 @Override 160 public Comparator<? super V> valueComparator() { 161 return valueComparator; 162 } 163 164 /** @since 14.0 (present with return type {@code SortedSet} since 2.0) */ 165 @Override 166 @GwtIncompatible // NavigableSet 167 public NavigableSet<V> get(@ParametricNullness K key) { 168 return (NavigableSet<V>) super.get(key); 169 } 170 171 /** 172 * {@inheritDoc} 173 * 174 * <p>Because a {@code TreeMultimap} has unique sorted keys, this method returns a {@link 175 * NavigableSet}, instead of the {@link java.util.Set} specified in the {@link Multimap} 176 * interface. 177 * 178 * @since 14.0 (present with return type {@code SortedSet} since 2.0) 179 */ 180 @Override 181 public NavigableSet<K> keySet() { 182 return (NavigableSet<K>) super.keySet(); 183 } 184 185 /** 186 * {@inheritDoc} 187 * 188 * <p>Because a {@code TreeMultimap} has unique sorted keys, this method returns a {@link 189 * NavigableMap}, instead of the {@link java.util.Map} specified in the {@link Multimap} 190 * interface. 191 * 192 * @since 14.0 (present with return type {@code SortedMap} since 2.0) 193 */ 194 @Override 195 public NavigableMap<K, Collection<V>> asMap() { 196 return (NavigableMap<K, Collection<V>>) super.asMap(); 197 } 198 199 /** 200 * @serialData key comparator, value comparator, number of distinct keys, and then for each 201 * distinct key: the key, number of values for that key, and key values 202 */ 203 @GwtIncompatible // java.io.ObjectOutputStream 204 private void writeObject(ObjectOutputStream stream) throws IOException { 205 stream.defaultWriteObject(); 206 stream.writeObject(keyComparator()); 207 stream.writeObject(valueComparator()); 208 Serialization.writeMultimap(this, stream); 209 } 210 211 @GwtIncompatible // java.io.ObjectInputStream 212 @SuppressWarnings("unchecked") // reading data stored by writeObject 213 private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException { 214 stream.defaultReadObject(); 215 keyComparator = checkNotNull((Comparator<? super K>) stream.readObject()); 216 valueComparator = checkNotNull((Comparator<? super V>) stream.readObject()); 217 setMap(new TreeMap<K, Collection<V>>(keyComparator)); 218 Serialization.populateMultimap(this, stream); 219 } 220 221 @GwtIncompatible // not needed in emulated source 222 private static final long serialVersionUID = 0; 223}