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:
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate classprivate static classNested classes/interfaces inherited from class com.google.common.collect.AbstractMultiset
AbstractMultiset.ElementSetNested classes/interfaces inherited from interface com.google.common.collect.Multiset
Multiset.Entry<E> -
Field Summary
FieldsModifier and TypeFieldDescriptionprivate final ConcurrentMap<E,AtomicInteger> The number of occurrences of each element.private static final long -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionintAdds a number of occurrences of the specified element to this multiset.voidclear()intReturns the number of occurrences ofelementin this multiset.static <E> ConcurrentHashMultiset<E>create()Creates a new, emptyConcurrentHashMultisetusing the default initial capacity, load factor, and concurrency settings.static <E> ConcurrentHashMultiset<E>Creates a newConcurrentHashMultisetcontaining 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, emptyConcurrentHashMultisetusingcountMapas 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>>booleanisEmpty()iterator()private voidreadObject(ObjectInputStream stream) intRemoves a number of occurrences of the specified element from this multiset.booleanremoveExactly(Object element, int occurrences) Removes exactly the specified number of occurrences ofelement, or makes no change if this is not possible.intAdds or removes occurrences ofelementsuch that thecount(java.lang.Object)of the element becomescount.booleanSets the number of occurrences ofelementtonewCount, but only if the count is currentlyexpectedOldCount.intsize()Returns the total number of all occurrences of all elements in this multiset.snapshot()Object[]toArray()<T> T[]toArray(T[] array) private voidwriteObject(ObjectOutputStream stream) Methods inherited from class com.google.common.collect.AbstractMultiset
add, addAll, contains, elementSet, entrySet, equals, hashCode, remove, removeAll, retainAll, toStringMethods inherited from class java.util.AbstractCollection
containsAllMethods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, waitMethods inherited from interface java.util.Collection
parallelStream, removeIf, stream, toArrayMethods 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:
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Constructor Details
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ConcurrentHashMultiset
ConcurrentHashMultiset(ConcurrentMap<E, AtomicInteger> countMap)
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Method Details
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create
Creates a new, emptyConcurrentHashMultisetusing the default initial capacity, load factor, and concurrency settings. -
create
Creates a newConcurrentHashMultisetcontaining the specified elements, using the default initial capacity, load factor, and concurrency settings.This implementation is highly efficient when
elementsis itself aMultiset.- Parameters:
elements- the elements that the multiset should contain
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create
Creates a new, emptyConcurrentHashMultisetusingcountMapas 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- ifcountMapis not empty- Since:
- 20.0
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count
Returns the number of occurrences ofelementin 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:
sizein interfaceCollection<E>- Specified by:
sizein interfaceMultiset<E>- Specified by:
sizein classAbstractCollection<E>
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toArray
- Specified by:
toArrayin interfaceCollection<E>- Overrides:
toArrayin classAbstractCollection<E>
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toArray
public <T> T[] toArray(T[] array) - Specified by:
toArrayin interfaceCollection<E>- Overrides:
toArrayin classAbstractCollection<E>
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snapshot
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add
Adds a number of occurrences of the specified element to this multiset.- Specified by:
addin interfaceMultiset<E>- Overrides:
addin 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- ifoccurrencesis negative, or if the resulting amount would exceedInteger.MAX_VALUE
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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:
removein interfaceMultiset<E>- Overrides:
removein 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- ifoccurrencesis negative
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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 ofelementto remove- Returns:
trueif the removal was possible (including ifoccurrencesis zero)- Throws:
IllegalArgumentException- ifoccurrencesis negative
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setCount
Adds or removes occurrences ofelementsuch that thecount(java.lang.Object)of the element becomescount.- Specified by:
setCountin interfaceMultiset<E>- Overrides:
setCountin 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
elementin the multiset before this call - Throws:
IllegalArgumentException- ifcountis negative
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setCount
Sets the number of occurrences ofelementtonewCount, but only if the count is currentlyexpectedOldCount. Ifelementdoes not appear in the multiset exactlyexpectedOldCounttimes, no changes will be made.- Specified by:
setCountin interfaceMultiset<E>- Overrides:
setCountin 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:
trueif the change was successful. This usually indicates that the multiset has been modified, but not always: in the case thatexpectedOldCount == newCount, the method will returntrueif the condition was met.- Throws:
IllegalArgumentException- ifexpectedOldCountornewCountis negative
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createElementSet
Description copied from class:AbstractMultisetCreates a new instance of this multiset's element set, which will be returned byAbstractMultiset.elementSet().- Overrides:
createElementSetin classAbstractMultiset<E>
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elementIterator
- Specified by:
elementIteratorin classAbstractMultiset<E>
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createEntrySet
Deprecated.Internal method, useAbstractMultiset.entrySet().- Overrides:
createEntrySetin classAbstractMultiset<E>
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distinctElements
int distinctElements()- Specified by:
distinctElementsin classAbstractMultiset<E>
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isEmpty
public boolean isEmpty()- Specified by:
isEmptyin interfaceCollection<E>- Overrides:
isEmptyin classAbstractMultiset<E>
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entryIterator
Iterator<Multiset.Entry<E>> entryIterator()- Specified by:
entryIteratorin classAbstractMultiset<E>
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iterator
Description copied from interface:MultisetElements that occur multiple times in the multiset will appear multiple times in this iterator, though not necessarily sequentially.
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clear
public void clear()- Specified by:
clearin interfaceCollection<E>- Specified by:
clearin classAbstractMultiset<E>
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writeObject
- Throws:
IOException
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readObject
- Throws:
IOExceptionClassNotFoundException
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AbstractMultiset.entrySet().