Interface ListMultimap<K extends @Nullable Object,V extends @Nullable Object>
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- All Superinterfaces:
Multimap<K,V>
- All Known Implementing Classes:
ArrayListMultimap
,ForwardingListMultimap
,ImmutableListMultimap
,LinkedListMultimap
@GwtCompatible public interface ListMultimap<K extends @Nullable Object,V extends @Nullable Object> extends Multimap<K,V>
AMultimap
that can hold duplicate key-value pairs and that maintains the insertion ordering of values for a given key. See theMultimap
documentation for information common to all multimaps.The
get(K)
,removeAll(java.lang.Object)
, andreplaceValues(K, java.lang.Iterable<? extends V>)
methods each return aList
of values. Though the method signature doesn't say so explicitly, the map returned byasMap()
hasList
values.See the Guava User Guide article on
Multimap
.- Since:
- 2.0
- Author:
- Jared Levy
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description Map<K,Collection<V>>
asMap()
Returns a view of this multimap as aMap
from each distinct key to the nonempty collection of that key's associated values.boolean
equals(Object obj)
Compares the specified object to this multimap for equality.List<V>
get(K key)
Returns a view collection of the values associated withkey
in this multimap, if any.List<V>
removeAll(Object key)
Removes all values associated with the keykey
.List<V>
replaceValues(K key, Iterable<? extends V> values)
Stores a collection of values with the same key, replacing any existing values for that key.
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Method Detail
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get
List<V> get(K key)
Returns a view collection of the values associated withkey
in this multimap, if any. Note that whencontainsKey(key)
is false, this returns an empty collection, notnull
.Changes to the returned collection will update the underlying multimap, and vice versa.
Because the values for a given key may have duplicates and follow the insertion ordering, this method returns a
List
, instead of theCollection
specified in theMultimap
interface.
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removeAll
@CanIgnoreReturnValue List<V> removeAll(@CheckForNull Object key)
Removes all values associated with the keykey
.Once this method returns,
key
will not be mapped to any values, so it will not appear inMultimap.keySet()
,Multimap.asMap()
, or any other views.Because the values for a given key may have duplicates and follow the insertion ordering, this method returns a
List
, instead of theCollection
specified in theMultimap
interface.
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replaceValues
@CanIgnoreReturnValue List<V> replaceValues(K key, Iterable<? extends V> values)
Stores a collection of values with the same key, replacing any existing values for that key.If
values
is empty, this is equivalent toremoveAll(key)
.Because the values for a given key may have duplicates and follow the insertion ordering, this method returns a
List
, instead of theCollection
specified in theMultimap
interface.- Specified by:
replaceValues
in interfaceMultimap<K extends @Nullable Object,V extends @Nullable Object>
- Returns:
- the collection of replaced values, or an empty collection if no values were previously associated with the key. The collection may be modifiable, but updating it will have no effect on the multimap.
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asMap
Map<K,Collection<V>> asMap()
Returns a view of this multimap as aMap
from each distinct key to the nonempty collection of that key's associated values. Note thatthis.asMap().get(k)
is equivalent tothis.get(k)
only whenk
is a key contained in the multimap; otherwise it returnsnull
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
orputAll
, nor do its entries supportsetValue
.Note: The returned map's values are guaranteed to be of type
List
. To obtain this map with the more specific generic typeMap<K, List<V>>
, callMultimaps.asMap(ListMultimap)
instead.
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equals
boolean equals(@CheckForNull Object obj)
Compares the specified object to this multimap for equality.Two
ListMultimap
instances are equal if, for each key, they contain the same values in the same order. If the value orderings disagree, the multimaps will not be considered equal.An empty
ListMultimap
is equal to any other emptyMultimap
, including an emptySetMultimap
.- Specified by:
equals
in interfaceMultimap<K extends @Nullable Object,V extends @Nullable Object>
- Overrides:
equals
in classObject
- Parameters:
obj
- the reference object with which to compare.- Returns:
true
if this object is the same as the obj argument;false
otherwise.- See Also:
Object.hashCode()
,HashMap
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