Class HashMultimap<K,V>
- java.lang.Object
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- com.google.common.collect.AbstractMultimap<K,V>
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- com.google.common.collect.AbstractMapBasedMultimap<K,V>
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- com.google.common.collect.AbstractSetMultimap<K,V>
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- com.google.common.collect.HashMultimapGwtSerializationDependencies<K,V>
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- com.google.common.collect.HashMultimap<K,V>
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- All Implemented Interfaces:
Multimap<K,V>
,SetMultimap<K,V>
,java.io.Serializable
public final class HashMultimap<K,V> extends HashMultimapGwtSerializationDependencies<K,V>
Implementation ofMultimap
using hash tables.The multimap does not store duplicate key-value pairs. Adding a new key-value pair equal to an existing key-value pair has no effect.
Keys and values may be null. All optional multimap methods are supported, and all returned views are modifiable.
This class is not threadsafe when any concurrent operations update the multimap. Concurrent read operations will work correctly if the last write happens-before any reads. To allow concurrent update operations, wrap your multimap with a call to
Multimaps.synchronizedSetMultimap(com.google.common.collect.SetMultimap<K, V>)
.- Since:
- 2.0
- See Also:
- Serialized Form
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Nested Class Summary
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Nested classes/interfaces inherited from class com.google.common.collect.AbstractMapBasedMultimap
AbstractMapBasedMultimap.NavigableAsMap, AbstractMapBasedMultimap.NavigableKeySet, AbstractMapBasedMultimap.WrappedCollection, AbstractMapBasedMultimap.WrappedList, AbstractMapBasedMultimap.WrappedNavigableSet, AbstractMapBasedMultimap.WrappedSet, AbstractMapBasedMultimap.WrappedSortedSet
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Nested classes/interfaces inherited from class com.google.common.collect.AbstractMultimap
AbstractMultimap.Entries, AbstractMultimap.EntrySet, AbstractMultimap.Values
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Field Summary
Fields Modifier and Type Field Description private static int
DEFAULT_VALUES_PER_KEY
(package private) int
expectedValuesPerKey
private static long
serialVersionUID
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Constructor Summary
Constructors Modifier Constructor Description private
HashMultimap()
private
HashMultimap(int expectedKeys, int expectedValuesPerKey)
private
HashMultimap(Multimap<? extends K,? extends V> multimap)
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static <K,V>
HashMultimap<K,V>create()
Creates a new, emptyHashMultimap
with the default initial capacities.static <K,V>
HashMultimap<K,V>create(int expectedKeys, int expectedValuesPerKey)
Constructs an emptyHashMultimap
with enough capacity to hold the specified numbers of keys and values without rehashing.static <K,V>
HashMultimap<K,V>create(Multimap<? extends K,? extends V> multimap)
Constructs aHashMultimap
with the same mappings as the specified multimap.(package private) java.util.Set<V>
createCollection()
Creates the collection of values for a single key.private void
readObject(java.io.ObjectInputStream stream)
private void
writeObject(java.io.ObjectOutputStream stream)
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Methods inherited from class com.google.common.collect.AbstractSetMultimap
asMap, createUnmodifiableEmptyCollection, entries, equals, get, put, removeAll, replaceValues, unmodifiableCollectionSubclass, wrapCollection
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Methods inherited from class com.google.common.collect.AbstractMapBasedMultimap
backingMap, clear, containsKey, createAsMap, createCollection, createEntries, createKeys, createKeySet, createMaybeNavigableAsMap, createMaybeNavigableKeySet, createValues, entryIterator, entrySpliterator, forEach, setMap, size, valueIterator, values, valueSpliterator, wrapList
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Methods inherited from class com.google.common.collect.AbstractMultimap
containsEntry, containsValue, hashCode, isEmpty, keys, keySet, putAll, putAll, remove, toString
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface com.google.common.collect.Multimap
clear, containsEntry, containsKey, containsValue, forEach, hashCode, isEmpty, keys, keySet, putAll, putAll, remove, size, values
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Field Detail
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DEFAULT_VALUES_PER_KEY
private static final int DEFAULT_VALUES_PER_KEY
- See Also:
- Constant Field Values
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expectedValuesPerKey
transient int expectedValuesPerKey
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serialVersionUID
private static final long serialVersionUID
- See Also:
- Constant Field Values
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Method Detail
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create
public static <K,V> HashMultimap<K,V> create()
Creates a new, emptyHashMultimap
with the default initial capacities.This method will soon be deprecated in favor of
MultimapBuilder.hashKeys().hashSetValues().build()
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create
public static <K,V> HashMultimap<K,V> create(int expectedKeys, int expectedValuesPerKey)
Constructs an emptyHashMultimap
with enough capacity to hold the specified numbers of keys and values without rehashing.This method will soon be deprecated in favor of
MultimapBuilder.hashKeys(expectedKeys).hashSetValues(expectedValuesPerKey).build()
.- Parameters:
expectedKeys
- the expected number of distinct keysexpectedValuesPerKey
- the expected average number of values per key- Throws:
java.lang.IllegalArgumentException
- ifexpectedKeys
orexpectedValuesPerKey
is negative
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create
public static <K,V> HashMultimap<K,V> create(Multimap<? extends K,? extends V> multimap)
Constructs aHashMultimap
with the same mappings as the specified multimap. If a key-value mapping appears multiple times in the input multimap, it only appears once in the constructed multimap.This method will soon be deprecated in favor of
MultimapBuilder.hashKeys().hashSetValues().build(multimap)
.- Parameters:
multimap
- the multimap whose contents are copied to this multimap
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createCollection
java.util.Set<V> createCollection()
Creates the collection of values for a single key.Collections with weak, soft, or phantom references are not supported. Each call to
createCollection
should create a new instance.The returned collection class determines whether duplicate key-value pairs are allowed.
Creates an empty
HashSet
for a collection of values for one key.- Specified by:
createCollection
in classAbstractSetMultimap<K,V>
- Returns:
- a new
HashSet
containing a collection of values for one key
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writeObject
private void writeObject(java.io.ObjectOutputStream stream) throws java.io.IOException
- Throws:
java.io.IOException
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readObject
private void readObject(java.io.ObjectInputStream stream) throws java.io.IOException, java.lang.ClassNotFoundException
- Throws:
java.io.IOException
java.lang.ClassNotFoundException
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