@GwtCompatible public interface SetMultimap<K,V> extends Multimap<K,V>
Multimap
that cannot hold duplicate key-value pairs. Adding a key-value pair that's
already in the multimap has no effect. See the Multimap
documentation for information
common to all multimaps.
The get(K)
, removeAll(java.lang.Object)
, and replaceValues(K, java.lang.Iterable<? extends V>)
methods each return a Set
of values, while entries()
returns a Set
of map entries. Though the method
signature doesn't say so explicitly, the map returned by asMap()
has Set
values.
If the values corresponding to a single key should be ordered according to a Comparator
(or the natural order), see the SortedSetMultimap
subinterface.
Since the value collections are sets, the behavior of a SetMultimap
is not specified
if key or value objects already present in the multimap change in a manner that affects
equals
comparisons. Use caution if mutable objects are used as keys or values in a SetMultimap
.
See the Guava User Guide article on Multimap
.
Modifier and Type | Method and Description |
---|---|
Map<K,Collection<V>> |
asMap()
Returns a view of this multimap as a
Map from each distinct key to the nonempty
collection of that key's associated values. |
Set<Map.Entry<K,V>> |
entries()
Returns a view collection of all key-value pairs contained in this multimap, as
Map.Entry
instances. |
boolean |
equals(@Nullable Object obj)
Compares the specified object to this multimap for equality.
|
Set<V> |
get(K key)
Returns a view collection of the values associated with
key in this multimap, if any. |
Set<V> |
removeAll(@Nullable Object key)
Removes all values associated with the key
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.
|
Set<V> get(K key)
key
in this multimap, if any.
Note that when containsKey(key)
is false, this returns an empty collection, not null
.
Changes to the returned collection will update the underlying multimap, and vice versa.
Because a SetMultimap
has unique values for a given key, this method returns a
Set
, instead of the Collection
specified in the Multimap
interface.
@CanIgnoreReturnValue Set<V> removeAll(@Nullable Object key)
key
.
Once this method returns, key
will not be mapped to any values, so it will not
appear in Multimap.keySet()
, Multimap.asMap()
, or any other views.
Because a SetMultimap
has unique values for a given key, this method returns a
Set
, instead of the Collection
specified in the Multimap
interface.
@CanIgnoreReturnValue Set<V> replaceValues(K key, Iterable<? extends V> values)
If values
is empty, this is equivalent to removeAll(key)
.
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>
Set<Map.Entry<K,V>> entries()
Map.Entry
instances.
Changes to the returned collection or the entries it contains will update the underlying multimap, and vice versa. However, adding to the returned collection is not possible.
Because a SetMultimap
has unique values for a given key, this method returns a
Set
, instead of the Collection
specified in the Multimap
interface.
Map<K,Collection<V>> asMap()
Map
from each distinct key to the nonempty
collection of that key's associated values. Note that this.asMap().get(k)
is equivalent
to this.get(k)
only when k
is a key contained in the multimap; otherwise it
returns null
as opposed to an empty collection.
Changes to the returned map or the collections that serve as its values will update the
underlying multimap, and vice versa. The map does not support put
or putAll
,
nor do its entries support setValue
.
Note: The returned map's values are guaranteed to be of type Set
. To obtain
this map with the more specific generic type Map<K, Set<V>>
, call Multimaps.asMap(SetMultimap)
instead.
boolean equals(@Nullable Object obj)
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.
An empty SetMultimap
is equal to any other empty Multimap
, including an
empty ListMultimap
.
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