Class ConcurrentHashMultiset<E>
- All Implemented Interfaces:
Multiset<E>
,Serializable
,Iterable<E>
,Collection<E>
Multiset
operations (exceptions where noted). Null elements are not supported.
See the Guava User Guide article on Multiset
.
- Since:
- 2.0
- See Also:
-
Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate class
private static class
Nested classes/interfaces inherited from class com.google.common.collect.AbstractMultiset
AbstractMultiset.ElementSet
Nested classes/interfaces inherited from interface com.google.common.collect.Multiset
Multiset.Entry<E>
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate final ConcurrentMap
<E, AtomicInteger> The number of occurrences of each element.private static final long
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionint
Adds a number of occurrences of the specified element to this multiset.void
clear()
int
Returns the number of occurrences ofelement
in this multiset.static <E> ConcurrentHashMultiset
<E> create()
Creates a new, emptyConcurrentHashMultiset
using the default initial capacity, load factor, and concurrency settings.static <E> ConcurrentHashMultiset
<E> Creates a newConcurrentHashMultiset
containing the specified elements, using the default initial capacity, load factor, and concurrency settings.static <E> ConcurrentHashMultiset
<E> create
(ConcurrentMap<E, AtomicInteger> countMap) Creates a new, emptyConcurrentHashMultiset
usingcountMap
as the internal backing map.Creates a new instance of this multiset's element set, which will be returned byAbstractMultiset.elementSet()
.Deprecated.(package private) int
(package private) Iterator
<Multiset.Entry<E>> boolean
isEmpty()
iterator()
private void
readObject
(ObjectInputStream stream) int
Removes a number of occurrences of the specified element from this multiset.boolean
removeExactly
(Object element, int occurrences) Removes exactly the specified number of occurrences ofelement
, or makes no change if this is not possible.int
Adds or removes occurrences ofelement
such that thecount(java.lang.Object)
of the element becomescount
.boolean
Sets the number of occurrences ofelement
tonewCount
, but only if the count is currentlyexpectedOldCount
.int
size()
Returns the total number of all occurrences of all elements in this multiset.snapshot()
Object[]
toArray()
<T> T[]
toArray
(T[] array) private void
writeObject
(ObjectOutputStream stream) Methods inherited from class com.google.common.collect.AbstractMultiset
add, addAll, contains, elementSet, entrySet, equals, hashCode, remove, removeAll, retainAll, toString
Methods inherited from class java.util.AbstractCollection
containsAll
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface java.util.Collection
parallelStream, removeIf, stream, toArray
Methods inherited from interface com.google.common.collect.Multiset
containsAll, forEach, forEachEntry, spliterator
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Field Details
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countMap
The number of occurrences of each element. -
serialVersionUID
private static final long serialVersionUID- See Also:
-
-
Constructor Details
-
ConcurrentHashMultiset
ConcurrentHashMultiset(ConcurrentMap<E, AtomicInteger> countMap)
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Method Details
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create
Creates a new, emptyConcurrentHashMultiset
using the default initial capacity, load factor, and concurrency settings. -
create
Creates a newConcurrentHashMultiset
containing the specified elements, using the default initial capacity, load factor, and concurrency settings.This implementation is highly efficient when
elements
is itself aMultiset
.- Parameters:
elements
- the elements that the multiset should contain
-
create
Creates a new, emptyConcurrentHashMultiset
usingcountMap
as the internal backing map.This instance will assume ownership of
countMap
, and other code should not maintain references to the map or modify it in any way.The returned multiset is serializable if the input map is.
- Parameters:
countMap
- backing map for storing the elements in the multiset and their counts. It must be empty.- Throws:
IllegalArgumentException
- ifcountMap
is not empty- Since:
- 20.0
-
count
Returns the number of occurrences ofelement
in this multiset. -
size
public int size()Returns the total number of all occurrences of all elements in this multiset.Note: this method does not return the number of distinct elements in the multiset, which is given by
entrySet().size()
.If the data in the multiset is modified by any other threads during this method, it is undefined which (if any) of these modifications will be reflected in the result.
- Specified by:
size
in interfaceCollection<E>
- Specified by:
size
in interfaceMultiset<E>
- Specified by:
size
in classAbstractCollection<E>
-
toArray
- Specified by:
toArray
in interfaceCollection<E>
- Overrides:
toArray
in classAbstractCollection<E>
-
toArray
public <T> T[] toArray(T[] array) - Specified by:
toArray
in interfaceCollection<E>
- Overrides:
toArray
in classAbstractCollection<E>
-
snapshot
-
add
Adds a number of occurrences of the specified element to this multiset.- Specified by:
add
in interfaceMultiset<E>
- Overrides:
add
in classAbstractMultiset<E>
- Parameters:
element
- the element to addoccurrences
- the number of occurrences to add- Returns:
- the previous count of the element before the operation; possibly zero
- Throws:
IllegalArgumentException
- ifoccurrences
is negative, or if the resulting amount would exceedInteger.MAX_VALUE
-
remove
Removes a number of occurrences of the specified element from this multiset. If the multiset contains fewer than this number of occurrences to begin with, all occurrences will be removed.- Specified by:
remove
in interfaceMultiset<E>
- Overrides:
remove
in classAbstractMultiset<E>
- Parameters:
element
- the element whose occurrences should be removedoccurrences
- the number of occurrences of the element to remove- Returns:
- the count of the element before the operation; possibly zero
- Throws:
IllegalArgumentException
- ifoccurrences
is negative
-
removeExactly
Removes exactly the specified number of occurrences ofelement
, or makes no change if this is not possible.This method, in contrast to
remove(Object, int)
, has no effect when the element count is smaller thanoccurrences
.- Parameters:
element
- the element to removeoccurrences
- the number of occurrences ofelement
to remove- Returns:
true
if the removal was possible (including ifoccurrences
is zero)- Throws:
IllegalArgumentException
- ifoccurrences
is negative
-
setCount
Adds or removes occurrences ofelement
such that thecount(java.lang.Object)
of the element becomescount
.- Specified by:
setCount
in interfaceMultiset<E>
- Overrides:
setCount
in classAbstractMultiset<E>
- Parameters:
element
- the element to add or remove occurrences of; may be null only if explicitly allowed by the implementationcount
- the desired count of the element in this multiset- Returns:
- the count of
element
in the multiset before this call - Throws:
IllegalArgumentException
- ifcount
is negative
-
setCount
Sets the number of occurrences ofelement
tonewCount
, but only if the count is currentlyexpectedOldCount
. Ifelement
does not appear in the multiset exactlyexpectedOldCount
times, no changes will be made.- Specified by:
setCount
in interfaceMultiset<E>
- Overrides:
setCount
in classAbstractMultiset<E>
- Parameters:
element
- the element to conditionally set the count of; may be null only if explicitly allowed by the implementationexpectedOldCount
- the expected present count of the element in this multisetnewCount
- the desired count of the element in this multiset- Returns:
true
if the change was successful. This usually indicates that the multiset has been modified, but not always: in the case thatexpectedOldCount == newCount
, the method will returntrue
if the condition was met.- Throws:
IllegalArgumentException
- ifexpectedOldCount
ornewCount
is negative
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createElementSet
Description copied from class:AbstractMultiset
Creates a new instance of this multiset's element set, which will be returned byAbstractMultiset.elementSet()
.- Overrides:
createElementSet
in classAbstractMultiset<E>
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elementIterator
- Specified by:
elementIterator
in classAbstractMultiset<E>
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createEntrySet
Deprecated.Internal method, useAbstractMultiset.entrySet()
.- Overrides:
createEntrySet
in classAbstractMultiset<E>
-
distinctElements
int distinctElements()- Specified by:
distinctElements
in classAbstractMultiset<E>
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isEmpty
public boolean isEmpty()- Specified by:
isEmpty
in interfaceCollection<E>
- Overrides:
isEmpty
in classAbstractMultiset<E>
-
entryIterator
Iterator<Multiset.Entry<E>> entryIterator()- Specified by:
entryIterator
in classAbstractMultiset<E>
-
iterator
Description copied from interface:Multiset
Elements that occur multiple times in the multiset will appear multiple times in this iterator, though not necessarily sequentially.
-
clear
public void clear()- Specified by:
clear
in interfaceCollection<E>
- Specified by:
clear
in classAbstractMultiset<E>
-
writeObject
- Throws:
IOException
-
readObject
- Throws:
IOException
ClassNotFoundException
-
AbstractMultiset.entrySet()
.