Class TreeMultimap<K,V>
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- com.google.common.collect.TreeMultimap<K,V>
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- All Implemented Interfaces:
@GwtCompatible(serializable=true, emulated=true) public class TreeMultimap<K,V> extends
Implementation ofMultimap
whose keys and values are ordered by their natural ordering or by supplied comparators. In all cases, this implementation uses or instead of to determine equivalence of instances.Warning: The comparators or comparables used must be consistent with equals as explained by the class specification. Otherwise, the resulting multiset will violate the general contract of .
The collections returned by
keySet
andasMap
iterate through the keys according to the key comparator ordering or the natural ordering of the keys. Similarly,get
,removeAll
, andreplaceValues
return collections that iterate through the values according to the value comparator ordering or the natural ordering of the values. The collections generated byentries
,keys
, andvalues
iterate across the keys according to the above key ordering, and for each key they iterate across the values according to the value ordering.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.
Null keys and values are permitted (provided, of course, that the respective comparators support them). 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.synchronizedSortedSetMultimap(com.google.common.collect.SortedSetMultimap<K, V>)
.See the Guava User Guide article on .
- Since:
- 2.0
- Author:
- Jared Levy, Louis Wasserman
- See Also:
- Serialized Form
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description <<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, leaving it empty.boolean
key, value)
Returnstrue
if this multimap contains at least one key-value pair with the keykey
and the valuevalue
.boolean
key)
Returnstrue
if this multimap contains at least one key-value pair with the keykey
.boolean
value)
Returnstrue
if this multimap contains at least one key-value pair with the valuevalue
.static <K extends ,V extends >
TreeMultimap<K,V>create()
Creates an emptyTreeMultimap
ordered by the natural ordering of its keys and values.static <K extends ,V extends >
TreeMultimap<K,V>create(Multimap<? extends K,? extends V> multimap)
Constructs aTreeMultimap
, ordered by the natural ordering of its keys and values, with the same mappings as the specified multimap.static <K,V>
TreeMultimap<K,V><? super K> keyComparator, <? super V> valueComparator)
Creates an emptyTreeMultimap
instance using explicit comparators.<<K,V>>
entries()
Returns a view collection of all key-value pairs contained in this multimap, as instances.boolean
object)
Compares the specified object to this multimap for equality.void
<? super K,? super V> action)
Performs the given action for all key-value pairs contained in this multimap.<V>
K key)
Returns a collection view of all values associated with a key.int
hashCode()
Returns the hash code for this multimap.boolean
isEmpty()
Returnstrue
if this multimap contains no key-value pairs.<? super K>
keyComparator()
Deprecated.Use((NavigableSet<K>) multimap.keySet()).comparator()
instead.Multiset<K>
keys()
Returns a view collection containing the key from each key-value pair in this multimap, without collapsing duplicates.<K>
keySet()
Returns a view collection of all distinct keys contained in this multimap.boolean
K key, V value)
Stores a key-value pair in the multimap.boolean
K key, <? extends V> values)
Stores a key-value pair in this multimap for each ofvalues
, all using the same key,key
.boolean
putAll(Multimap<? extends K,? extends V> multimap)
Stores all key-value pairs ofmultimap
in this multimap, in the order returned bymultimap.entries()
.boolean
key, value)
Removes a single key-value pair with the keykey
and the valuevalue
from this multimap, if such exists.<V>
key)
Removes all values associated with a given key.<V>
K key, <? 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 this multimap.toString()
Returns a string representation of the multimap, generated by callingtoString
on the map returned byMultimap.asMap()
.<? super V>
valueComparator()
Returns the comparator that orders the multimap values, withnull
indicating that natural ordering is used.<V>
values()
Returns a view collection containing the value from each key-value pair contained in this multimap, without collapsing duplicates (sovalues().size() == size()
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Methods inherited from interface com.google.common.collect.Multimap
clear, containsEntry, containsKey, containsValue, forEach, hashCode, isEmpty, keys, put, putAll, putAll, remove, size
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Methods inherited from interface com.google.common.collect.SetMultimap
entries, equals
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Method Detail
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create
public static <K extends ,V extends > TreeMultimap<K,V> create()
Creates an emptyTreeMultimap
ordered by the natural ordering of its keys and values.
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create
public static <K,V> <? super K> keyComparator, <? super V> valueComparator)
Creates an emptyTreeMultimap
instance using explicit comparators. Neither comparator may be null; useOrdering.natural()
to specify natural order.- Parameters:
keyComparator
- the comparator that determines the key orderingvalueComparator
- the comparator that determines the value ordering
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create
public static <K extends ,V extends > TreeMultimap<K,V> create(Multimap<? extends K,? extends V> multimap)
Constructs aTreeMultimap
, ordered by the natural ordering of its keys and values, with the same mappings as the specified multimap.- Parameters:
multimap
- the multimap whose contents are copied to this multimap
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keyComparator
public <? super K> keyComparator()
Deprecated.Use((NavigableSet<K>) multimap.keySet()).comparator()
instead.Returns the comparator that orders the multimap keys.
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valueComparator
public <? super V> valueComparator()
Description copied from interface:SortedSetMultimap
Returns the comparator that orders the multimap values, withnull
indicating that natural ordering is used.
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get
@GwtIncompatible public < K key)
Returns a collection view of all values associated with a key. If no mappings in the multimap have the provided key, an empty collection is returned.Changes to the returned collection will update the underlying multimap, and vice versa.
Because a
SortedSetMultimap
has unique sorted values for a given key, this method returns a , instead of the specified in theMultimap
interface.
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keySet
public <K> keySet()
Returns a view collection of all distinct keys contained in this multimap. Note that the key set contains a key if and only if this multimap maps that key to at least one value.Changes to the returned set will update the underlying multimap, and vice versa. However, adding to the returned set is not possible.
Because a
TreeMultimap
has unique sorted keys, this method returns a , instead of the specified in theMultimap
interface.
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asMap
public <<V>> asMap()
Returns a map view that associates each key with the corresponding values in the multimap. Changes to the returned map, such as element removal, will update the underlying multimap. The map does not supportsetValue
on its entries,put
, orputAll
.When passed a key that is present in the map,
asMap().get(Object)
has the same behavior asSortedSetMultimap.get(K)
, returning a live collection. When passed a key that is not present, however,asMap().get(Object)
returnsnull
instead of an empty collection.Though the method signature doesn't say so explicitly, the returned map has values.
Because a
TreeMultimap
has unique sorted keys, this method returns a , instead of the specified in theMultimap
interface.
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removeAll
public <V> removeAll( key)
Removes all values associated with a given key. The returned collection is immutable.Because a
SortedSetMultimap
has unique sorted values for a given key, this method returns a , instead of the specified in theMultimap
interface.- Specified by:
removeAll
in interfaceMultimap<K,V>
- Specified by:
removeAll
in interfaceSetMultimap<K,V>
- Specified by:
removeAll
in interfaceSortedSetMultimap<K,V>
- Returns:
- the values that were removed (possibly empty). The returned collection may be modifiable, but updating it will have no effect on the multimap.
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replaceValues
public <V> replaceValues( K key, <? extends V> values)
Stores a collection of values with the same key, replacing any existing values for that key. The returned collection is immutable.Because a
SortedSetMultimap
has unique sorted values for a given key, this method returns a , instead of the specified in theMultimap
interface.Any duplicates in
values
will be stored in the multimap once.- Specified by:
replaceValues
in interfaceMultimap<K,V>
- Specified by:
replaceValues
in interfaceSetMultimap<K,V>
- Specified by:
replaceValues
in interfaceSortedSetMultimap<K,V>
- 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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values
public <V> values()
Returns a view collection containing the value from each key-value pair contained in this multimap, without collapsing duplicates (sovalues().size() == size()
).Changes to the returned collection will update the underlying multimap, and vice versa. However, adding to the returned collection is not possible.
The iterator generated by the returned collection traverses the values for one key, followed by the values of a second key, and so on.
Consequently, the values do not follow their natural ordering or the ordering of the value comparator.
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entries
public <<K,V>> entries()
Returns a view collection of all key-value pairs contained in this multimap, as 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.
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 , instead of the specified in theMultimap
interface.- Specified by:
entries
in interfaceMultimap<K,V>
- Specified by:
entries
in interfaceSetMultimap<K,V>
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put
public boolean put( K key, V value)
Stores a key-value pair in the multimap.
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equals
public boolean equals( object)
Compares the specified object to this multimap for equality.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.- Specified by:
equals
in interfaceMultimap<K,V>
- Specified by:
equals
in interfaceSetMultimap<K,V>
- Parameters:
object
- the reference object with which to compare.- Returns:
true
if this object is the same as the obj argument;false
otherwise.- See Also:
- ,
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size
public int size()
Description copied from interface:Multimap
Returns the number of key-value pairs in this multimap.Note: this method does not return the number of distinct keys in the multimap, which is given by
keySet().size()
orasMap().size()
. See the opening section of theMultimap
class documentation for clarification.
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containsKey
public boolean containsKey( key)
Description copied from interface:Multimap
Returnstrue
if this multimap contains at least one key-value pair with the keykey
.- Specified by:
containsKey
in interfaceMultimap<K,V>
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clear
public void clear()
Description copied from interface:Multimap
Removes all key-value pairs from the multimap, leaving it empty.
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forEach
public void forEach(<? super K,? super V> action)
Description copied from interface:Multimap
Performs the given action for all key-value pairs contained in this multimap. If an ordering is specified by theMultimap
implementation, actions will be performed in the order of iteration ofMultimap.entries()
. Exceptions thrown by the action are relayed to the caller.To loop over all keys and their associated value collections, write
Multimaps.asMap(multimap).forEach((key, valueCollection) -> action())
.
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isEmpty
public boolean isEmpty()
Description copied from interface:Multimap
Returnstrue
if this multimap contains no key-value pairs. Equivalent tosize() == 0
, but can in some cases be more efficient.
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containsValue
public boolean containsValue( value)
Description copied from interface:Multimap
Returnstrue
if this multimap contains at least one key-value pair with the valuevalue
.- Specified by:
containsValue
in interfaceMultimap<K,V>
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containsEntry
public boolean containsEntry( key, value)
Description copied from interface:Multimap
Returnstrue
if this multimap contains at least one key-value pair with the keykey
and the valuevalue
.- Specified by:
containsEntry
in interfaceMultimap<K,V>
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remove
public boolean remove( key, value)
Description copied from interface:Multimap
Removes a single key-value pair with the keykey
and the valuevalue
from this multimap, if such exists. If multiple key-value pairs in the multimap fit this description, which one is removed is unspecified.
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putAll
public boolean putAll( K key, <? extends V> values)
Description copied from interface:Multimap
Stores a key-value pair in this multimap for each ofvalues
, all using the same key,key
. Equivalent to (but expected to be more efficient than):for (V value : values) { put(key, value); }
In particular, this is a no-op if
values
is empty.
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putAll
public boolean putAll(Multimap<? extends K,? extends V> multimap)
Description copied from interface:Multimap
Stores all key-value pairs ofmultimap
in this multimap, in the order returned bymultimap.entries()
.
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keys
public Multiset<K> keys()
Description copied from interface:Multimap
Returns a view collection containing the key from each key-value pair in this multimap, without collapsing duplicates. This collection has the same size as this multimap, andkeys().count(k) == get(k).size()
for allk
.Changes to the returned multiset will update the underlying multimap, and vice versa. However, adding to the returned collection is not possible.
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hashCode
public int hashCode()
Returns the hash code for this multimap.The hash code of a multimap is defined as the hash code of the map view, as returned by
Multimap.asMap()
.
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toString
public toString()
Returns a string representation of the multimap, generated by callingtoString
on the map returned byMultimap.asMap()
.- Overrides:
in class
- Returns:
- a string representation of the multimap
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