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java.lang.Objectcom.google.common.collect.HashMultimap<K,V>
@GwtCompatible(serializable=true,
emulated=true)
public final class HashMultimap<K,V>
Implementation of Multimap 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. To allow concurrent
update operations, wrap your multimap with a call to Multimaps.synchronizedSetMultimap(com.google.common.collect.SetMultimap.
| Method Summary | ||
|---|---|---|
Map<K,Collection<V>> |
asMap()
Returns a map view that associates each key with the corresponding values in the multimap. |
|
void |
clear()
Removes all key-value pairs from the multimap. |
|
boolean |
containsEntry(Object key,
Object value)
Returns true if the multimap contains the specified key-value pair. |
|
boolean |
containsKey(Object key)
Returns true if the multimap contains any values for the specified
key. |
|
boolean |
containsValue(Object value)
Returns true if the multimap contains the specified value for any
key. |
|
static
|
create()
Creates a new, empty HashMultimap with the default initial
capacities. |
|
static
|
create(int expectedKeys,
int expectedValuesPerKey)
Constructs an empty HashMultimap with enough capacity to hold the
specified numbers of keys and values without rehashing. |
|
static
|
create(Multimap<? extends K,? extends V> multimap)
Constructs a HashMultimap with the same mappings as the specified
multimap. |
|
Set<Map.Entry<K,V>> |
entries()
Returns a collection of all key-value pairs. |
|
boolean |
equals(Object object)
Compares the specified object to this multimap for equality. |
|
Set<V> |
get(K key)
Returns a collection view of all values associated with a key. |
|
int |
hashCode()
Returns the hash code for this multimap. |
|
boolean |
isEmpty()
Returns true if the multimap contains no key-value pairs. |
|
Multiset<K> |
keys()
Returns a collection, which may contain duplicates, of all keys. |
|
Set<K> |
keySet()
Returns the set of all keys, each appearing once in the returned set. |
|
boolean |
put(K key,
V value)
Stores a key-value pair in the multimap. |
|
boolean |
putAll(K key,
Iterable<? extends V> values)
Stores a collection of values with the same key. |
|
boolean |
putAll(Multimap<? extends K,? extends V> multimap)
Copies all of another multimap's key-value pairs into this multimap. |
|
boolean |
remove(Object key,
Object value)
Removes a key-value pair from the multimap. |
|
Set<V> |
removeAll(Object key)
Removes all values associated with a given key. |
|
Set<V> |
replaceValues(K key,
Iterable<? extends V> values)
Stores a collection of values with the same key, replacing any existing values for that key. |
|
int |
size()
Returns the number of key-value pairs in the multimap. |
|
String |
toString()
Returns a string representation of the multimap, generated by calling toString on the map returned by Multimap.asMap(). |
|
Collection<V> |
values()
Returns a collection of all values in the multimap. |
|
| Methods inherited from class java.lang.Object |
|---|
clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
| Methods inherited from interface com.google.common.collect.Multimap |
|---|
clear, containsEntry, containsKey, containsValue, hashCode, isEmpty, keys, keySet, putAll, putAll, remove, size, values |
| Method Detail |
|---|
public static <K,V> HashMultimap<K,V> create()
HashMultimap with the default initial
capacities.
public static <K,V> HashMultimap<K,V> create(int expectedKeys,
int expectedValuesPerKey)
HashMultimap with enough capacity to hold the
specified numbers of keys and values without rehashing.
expectedKeys - the expected number of distinct keysexpectedValuesPerKey - the expected average number of values per key
IllegalArgumentException - if expectedKeys or expectedValuesPerKey is negativepublic static <K,V> HashMultimap<K,V> create(Multimap<? extends K,? extends V> multimap)
HashMultimap 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.
multimap - the multimap whose contents are copied to this multimap
public Set<V> get(@Nullable
K key)
Changes to the returned collection will update the underlying multimap, and vice versa.
The returned collection is not serializable.
Because a SetMultimap has unique values for a given key, this
method returns a Set, instead of the Collection specified
in the Multimap interface.
get in interface Multimap<K,V>get in interface SetMultimap<K,V>key - key to search for in multimap
public Set<Map.Entry<K,V>> entries()
add or addAll operations.
The iterator generated by the returned collection traverses the values for one key, followed by the values of a second key, and so on.
Each entry is an immutable snapshot of a key-value mapping in the multimap, taken at the time the entry is returned by a method call to the collection or its iterator.
Because a SetMultimap has unique values for a given key, this
method returns a Set, instead of the Collection specified
in the Multimap interface.
entries in interface Multimap<K,V>entries in interface SetMultimap<K,V>
public Set<V> removeAll(@Nullable
Object key)
The returned collection is immutable.
Because a SetMultimap has unique values for a given key, this
method returns a Set, instead of the Collection specified
in the Multimap interface.
removeAll in interface Multimap<K,V>removeAll in interface SetMultimap<K,V>key - key of entries to remove from the multimap
public Set<V> replaceValues(@Nullable
K key,
Iterable<? extends V> values)
The returned collection is immutable.
Because a SetMultimap has unique values for a given key, this
method returns a Set, instead of the Collection specified
in the Multimap interface.
Any duplicates in values will be stored in the multimap once.
replaceValues in interface Multimap<K,V>replaceValues in interface SetMultimap<K,V>key - key to store in the multimapvalues - values to store in the multimap
public Map<K,Collection<V>> asMap()
setValue()
on its entries, put, or putAll.
When passed a key that is present in the map, asMap().get(Object) has the same behavior as Multimap.get(K), returning a
live collection. When passed a key that is not present, however, asMap().get(Object) returns null instead of an empty collection.
Though the method signature doesn't say so explicitly, the returned map
has Set values.
asMap in interface Multimap<K,V>asMap in interface SetMultimap<K,V>
public boolean put(K key,
V value)
put in interface Multimap<K,V>key - key to store in the multimapvalue - value to store in the multimap
true if the method increased the size of the multimap, or
false if the multimap already contained the key-value pair
public boolean equals(@Nullable
Object object)
Two SetMultimap instances are equal if, for each key, they
contain the same values. Equality does not depend on the ordering of keys
or values.
equals in interface Multimap<K,V>equals in interface SetMultimap<K,V>public int size()
Multimap
size in interface Multimap<K,V>public boolean isEmpty()
Multimaptrue if the multimap contains no key-value pairs.
isEmpty in interface Multimap<K,V>
public boolean containsKey(@Nullable
Object key)
Multimaptrue if the multimap contains any values for the specified
key.
containsKey in interface Multimap<K,V>key - key to search for in multimap
public boolean containsValue(@Nullable
Object value)
Multimaptrue if the multimap contains the specified value for any
key.
containsValue in interface Multimap<K,V>value - value to search for in multimap
public boolean containsEntry(@Nullable
Object key,
@Nullable
Object value)
Multimaptrue if the multimap contains the specified key-value pair.
containsEntry in interface Multimap<K,V>key - key to search for in multimapvalue - value to search for in multimap
public boolean remove(@Nullable
Object key,
@Nullable
Object value)
Multimap
remove in interface Multimap<K,V>key - key of entry to remove from the multimapvalue - value of entry to remove the multimap
true if the multimap changed
public boolean putAll(@Nullable
K key,
Iterable<? extends V> values)
Multimap
putAll in interface Multimap<K,V>key - key to store in the multimapvalues - values to store in the multimap
true if the multimap changedpublic boolean putAll(Multimap<? extends K,? extends V> multimap)
Multimapmultimap.entries().
putAll in interface Multimap<K,V>multimap - mappings to store in this multimap
true if the multimap changedpublic void clear()
Multimap
clear in interface Multimap<K,V>public Set<K> keySet()
Multimap
keySet in interface Multimap<K,V>public Multiset<K> keys()
Multimap
keys in interface Multimap<K,V>public Collection<V> values()
The iterator generated by the returned collection traverses the values for one key, followed by the values of a second key, and so on.
values in interface Multimap<K,V>public int hashCode()
The hash code of a multimap is defined as the hash code of the map view,
as returned by Multimap.asMap().
hashCode in interface Multimap<K,V>hashCode in class ObjectMap.hashCode()public String toString()
toString on the map returned by Multimap.asMap().
toString in class Object
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