@GwtIncompatible public final class ConcurrentHashMultiset<E> extends AbstractCollection<E> implements Serializable
Multiset operations (exceptions where noted). Null elements are not supported.
See the Guava User Guide article on Multiset.
Multiset.Entry<E>| Modifier and Type | Method and Description |
|---|---|
boolean |
add(E element)
Adds a single occurrence of the specified element to this multiset.
|
int |
add(E element,
int occurrences)
Adds a number of occurrences of the specified element to this multiset.
|
boolean |
addAll(Collection<? extends E> elementsToAdd) |
void |
clear() |
boolean |
contains(@Nullable Object element)
Determines whether this multiset contains the specified element.
|
int |
count(@Nullable Object element)
Returns the number of occurrences of
element in this multiset. |
static <E> ConcurrentHashMultiset<E> |
create()
Creates a new, empty
ConcurrentHashMultiset using the default initial capacity, load
factor, and concurrency settings. |
static <E> ConcurrentHashMultiset<E> |
create(ConcurrentMap<E,AtomicInteger> countMap)
Creates a new, empty
ConcurrentHashMultiset using countMap as the internal
backing map. |
static <E> ConcurrentHashMultiset<E> |
create(Iterable<? extends E> elements)
Creates a new
ConcurrentHashMultiset containing the specified elements, using the
default initial capacity, load factor, and concurrency settings. |
Set<Multiset.Entry<E>> |
createEntrySet()
Deprecated.
Internal method, use
entrySet(). |
Set<E> |
elementSet()
Returns the set of distinct elements contained in this multiset.
|
Set<Multiset.Entry<E>> |
entrySet()
Returns a view of the contents of this multiset, grouped into
Multiset.Entry instances,
each providing an element of the multiset and the count of that element. |
boolean |
equals(@Nullable Object object)
Compares the specified object with this multiset for equality.
|
int |
hashCode()
Returns the hash code for this multiset.
|
boolean |
isEmpty() |
Iterator<E> |
iterator() |
boolean |
remove(@Nullable Object element)
Removes a single occurrence of the specified element from this multiset, if present.
|
int |
remove(@Nullable Object element,
int occurrences)
Removes a number of occurrences of the specified element from this multiset.
|
boolean |
removeAll(Collection<?> elementsToRemove) |
boolean |
removeExactly(@Nullable Object element,
int occurrences)
Removes exactly the specified number of occurrences of
element, or makes no change if
this is not possible. |
boolean |
retainAll(Collection<?> elementsToRetain) |
int |
setCount(E element,
int count)
Adds or removes occurrences of
element such that the count(java.lang.Object) of the element
becomes count. |
boolean |
setCount(E element,
int expectedOldCount,
int newCount)
Sets the number of occurrences of
element to newCount, but only if the count is
currently expectedOldCount. |
int |
size()
Returns the total number of all occurrences of all elements in this multiset.
|
Object[] |
toArray() |
<T> T[] |
toArray(T[] array) |
String |
toString() |
containsAllclone, finalize, getClass, notify, notifyAll, wait, wait, waitcontainsAll, forEach, forEachEntry, spliteratorparallelStream, removeIf, streampublic static <E> ConcurrentHashMultiset<E> create()
ConcurrentHashMultiset using the default initial capacity, load
factor, and concurrency settings.public static <E> ConcurrentHashMultiset<E> create(Iterable<? extends E> elements)
ConcurrentHashMultiset containing the specified elements, using the
default initial capacity, load factor, and concurrency settings.
This implementation is highly efficient when elements is itself a Multiset.
elements - the elements that the multiset should contain@Beta public static <E> ConcurrentHashMultiset<E> create(ConcurrentMap<E,AtomicInteger> countMap)
ConcurrentHashMultiset using countMap 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.
countMap - backing map for storing the elements in the multiset and their counts. It must
be empty.IllegalArgumentException - if countMap is not emptypublic int count(@Nullable Object element)
element in this multiset.public int size()
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.
size in interface Multiset<E>size in interface Collection<E>size in class AbstractCollection<E>public Object[] toArray()
toArray in interface Collection<E>toArray in class AbstractCollection<E>public <T> T[] toArray(T[] array)
toArray in interface Collection<E>toArray in class AbstractCollection<E>@CanIgnoreReturnValue public int add(E element, int occurrences)
add in interface Multiset<E>element - the element to addoccurrences - the number of occurrences to addIllegalArgumentException - if occurrences is negative, or if the resulting amount
would exceed Integer.MAX_VALUE@CanIgnoreReturnValue public int remove(@Nullable Object element, int occurrences)
remove in interface Multiset<E>element - the element whose occurrences should be removedoccurrences - the number of occurrences of the element to removeIllegalArgumentException - if occurrences is negative@CanIgnoreReturnValue public boolean removeExactly(@Nullable Object element, int occurrences)
element, 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 than occurrences.
element - the element to removeoccurrences - the number of occurrences of element to removetrue if the removal was possible (including if occurrences is zero)IllegalArgumentException - if occurrences is negative@CanIgnoreReturnValue public int setCount(E element, int count)
element such that the count(java.lang.Object) of the element
becomes count.setCount in interface Multiset<E>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 multisetelement in the multiset before this callIllegalArgumentException - if count is negative@CanIgnoreReturnValue public boolean setCount(E element, int expectedOldCount, int newCount)
element to newCount, but only if the count is
currently expectedOldCount. If element does not appear in the multiset exactly
expectedOldCount times, no changes will be made.setCount in interface Multiset<E>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 multisettrue if the change was successful. This usually indicates that the multiset has
been modified, but not always: in the case that expectedOldCount == newCount, the
method will return true if the condition was met.IllegalArgumentException - if expectedOldCount or newCount is negative@Deprecated public Set<Multiset.Entry<E>> createEntrySet()
entrySet().public boolean isEmpty()
isEmpty in interface Collection<E>public Iterator<E> iterator()
MultisetElements that occur multiple times in the multiset will appear multiple times in this iterator, though not necessarily sequentially.
public void clear()
clear in interface Collection<E>public boolean contains(@Nullable Object element)
MultisetThis method refines Collection.contains(java.lang.Object) to further specify that it may not
throw an exception in response to element being null or of the wrong type.
contains in interface Multiset<E>contains in interface Collection<E>contains in class AbstractCollection<E>element - the element to check fortrue if this multiset contains at least one occurrence of the element@CanIgnoreReturnValue public final boolean add(E element)
MultisetThis method refines Collection.add(E), which only ensures the presence of the
element, to further specify that a successful call must always increment the count of the
element, and the overall size of the collection, by one.
To both add the element and obtain the previous count of that element, use add(element, 1) instead.
add in interface Multiset<E>add in interface Collection<E>add in class AbstractCollection<E>element - the element to add one occurrence of; may be null only if explicitly allowed by
the implementationtrue always, since this call is required to modify the multiset, unlike other
Collection types@CanIgnoreReturnValue public final boolean remove(@Nullable Object element)
MultisetThis method refines Collection.remove(java.lang.Object) to further specify that it may not
throw an exception in response to element being null or of the wrong type.
To both remove the element and obtain the previous count of that element, use remove(element, 1) instead.
remove in interface Multiset<E>remove in interface Collection<E>remove in class AbstractCollection<E>element - the element to remove one occurrence oftrue if an occurrence was found and removed@CanIgnoreReturnValue public final boolean addAll(Collection<? extends E> elementsToAdd)
This implementation is highly efficient when elementsToAdd is itself a Multiset.
addAll in interface Collection<E>addAll in class AbstractCollection<E>@CanIgnoreReturnValue public final boolean removeAll(Collection<?> elementsToRemove)
MultisetNote: This method ignores how often any element might appear in c, and only
cares whether or not an element appears at all. If you wish to remove one occurrence in this
multiset for every occurrence in c, see Multisets.removeOccurrences(Multiset,
Multiset).
This method refines Collection.removeAll(java.util.Collection<?>) to further specify that it may not
throw an exception in response to any of elements being null or of the wrong type.
removeAll in interface Multiset<E>removeAll in interface Collection<E>removeAll in class AbstractCollection<E>@CanIgnoreReturnValue public final boolean retainAll(Collection<?> elementsToRetain)
MultisetNote: This method ignores how often any element might appear in c, and only
cares whether or not an element appears at all. If you wish to remove one occurrence in this
multiset for every occurrence in c, see Multisets.retainOccurrences(Multiset,
Multiset).
This method refines Collection.retainAll(java.util.Collection<?>) to further specify that it may not
throw an exception in response to any of elements being null or of the wrong type.
retainAll in interface Multiset<E>retainAll in interface Collection<E>retainAll in class AbstractCollection<E>Multisets.retainOccurrences(Multiset, Multiset)public Set<E> elementSet()
MultisetIf the element set supports any removal operations, these necessarily cause all occurrences of the removed element(s) to be removed from the multiset. Implementations are not expected to support the add operations, although this is possible.
A common use for the element set is to find the number of distinct elements in the multiset:
elementSet().size().
elementSet in interface Multiset<E>public Set<Multiset.Entry<E>> entrySet()
MultisetMultiset.Entry instances,
each providing an element of the multiset and the count of that element. This set contains
exactly one entry for each distinct element in the multiset (thus it always has the same size
as the Multiset.elementSet()). The order of the elements in the element set is unspecified.
The entry set is backed by the same data as the multiset, so any change to either is
immediately reflected in the other. However, multiset changes may or may not be reflected in
any Entry instances already retrieved from the entry set (this is
implementation-dependent). Furthermore, implementations are not required to support
modifications to the entry set at all, and the Entry instances themselves don't even
have methods for modification. See the specific implementation class for more details on how
its entry set handles modifications.
public final boolean equals(@Nullable Object object)
true if the
given object is also a multiset and contains equal elements with equal counts, regardless of
order.
This implementation returns true if object is a multiset of the same size
and if, for each element, the two multisets have the same count.
public final int hashCode()
((element == null) ? 0 : element.hashCode()) ^ count(element)
over all distinct elements in the multiset. It follows that a multiset and its entry set always have the same hash code.
This implementation returns the hash code of Multiset.entrySet().
public final String toString()
It is recommended, though not mandatory, that this method return the result of invoking
Multiset.toString() on the Multiset.entrySet(), yielding a result such as [a x 3, c, d x 2,
e].
This implementation returns the result of invoking toString on Multiset.entrySet().
toString in interface Multiset<E>toString in class AbstractCollection<E>Copyright © 2010–2019. All rights reserved.