@GwtIncompatible public final class ConcurrentHashMultiset<E> extends AbstractMultiset<E> implements java.io.Serializable
Multiset operations (exceptions where noted). Null elements are not supported.
See the Guava User Guide article on
Multiset.
| Modifier and Type | Class and Description |
|---|---|
private class |
ConcurrentHashMultiset.EntrySet |
private static class |
ConcurrentHashMultiset.FieldSettersHolder |
AbstractMultiset.ElementSetMultiset.Entry<E>| Modifier and Type | Field and Description |
|---|---|
private java.util.concurrent.ConcurrentMap<E,java.util.concurrent.atomic.AtomicInteger> |
countMap
The number of occurrences of each element.
|
private static long |
serialVersionUID |
| Constructor and Description |
|---|
ConcurrentHashMultiset(java.util.concurrent.ConcurrentMap<E,java.util.concurrent.atomic.AtomicInteger> countMap) |
| Modifier and Type | Method and Description |
|---|---|
int |
add(E element,
int occurrences)
Adds a number of occurrences of the specified element to this multiset.
|
void |
clear() |
int |
count(java.lang.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(java.util.concurrent.ConcurrentMap<E,java.util.concurrent.atomic.AtomicInteger> countMap)
Creates a new, empty
ConcurrentHashMultiset using countMap as the internal
backing map. |
static <E> ConcurrentHashMultiset<E> |
create(java.lang.Iterable<? extends E> elements)
Creates a new
ConcurrentHashMultiset containing the specified elements, using
the default initial capacity, load factor, and concurrency settings. |
static <E> ConcurrentHashMultiset<E> |
create(MapMaker mapMaker)
Deprecated.
Use
create(ConcurrentMap) instead. This method is scheduled for deletion
in Guava 21.0. |
(package private) java.util.Set<E> |
createElementSet()
Creates a new instance of this multiset's element set, which will be
returned by
AbstractMultiset.elementSet(). |
java.util.Set<Multiset.Entry<E>> |
createEntrySet() |
(package private) int |
distinctElements() |
(package private) java.util.Iterator<Multiset.Entry<E>> |
entryIterator() |
boolean |
isEmpty() |
private void |
readObject(java.io.ObjectInputStream stream) |
int |
remove(java.lang.Object element,
int occurrences)
Removes a number of occurrences of the specified element from this multiset.
|
boolean |
removeExactly(java.lang.Object element,
int occurrences)
Removes exactly the specified number of occurrences of
element, or makes no
change if this is not possible. |
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() |
private java.util.List<E> |
snapshot() |
java.lang.Object[] |
toArray() |
<T> T[] |
toArray(T[] array) |
private void |
writeObject(java.io.ObjectOutputStream stream) |
add, addAll, contains, elementSet, entrySet, equals, hashCode, iterator, remove, removeAll, retainAll, toStringclone, finalize, getClass, notify, notifyAll, wait, wait, waitcontainsAllprivate final transient java.util.concurrent.ConcurrentMap<E,java.util.concurrent.atomic.AtomicInteger> countMap
private static final long serialVersionUID
ConcurrentHashMultiset(java.util.concurrent.ConcurrentMap<E,java.util.concurrent.atomic.AtomicInteger> countMap)
public static <E> ConcurrentHashMultiset<E> create()
ConcurrentHashMultiset using the default
initial capacity, load factor, and concurrency settings.public static <E> ConcurrentHashMultiset<E> create(java.lang.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 @Deprecated public static <E> ConcurrentHashMultiset<E> create(MapMaker mapMaker)
create(ConcurrentMap) instead. This method is scheduled for deletion
in Guava 21.0.ConcurrentHashMultiset using mapMaker to construct the
internal backing map.
If this MapMaker is configured to use entry eviction of any kind, this eviction
applies to all occurrences of a given element as a single unit. However, most updates to the
multiset do not count as map updates at all, since we're usually just mutating the value stored
in the map, so MapMaker#expireAfterAccess makes sense (evict the entry that was queried
or updated longest ago), but MapMaker#expireAfterWrite doesn't, because the eviction
time is measured from when we saw the first occurrence of the object.
The returned multiset is serializable but any serialization caveats given in MapMaker apply.
Finally, soft/weak values can be used but are not very useful: the values are created internally and not exposed externally, so no one else will have a strong reference to the values. Weak keys on the other hand can be useful in some scenarios.
GenericMapMaker class)
since 7.0)@Beta public static <E> ConcurrentHashMultiset<E> create(java.util.concurrent.ConcurrentMap<E,java.util.concurrent.atomic.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.java.lang.IllegalArgumentException - if countMap is not emptypublic int count(@Nullable
java.lang.Object element)
element in this multiset.public int 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 java.util.Collection<E>size in class AbstractMultiset<E>public java.lang.Object[] toArray()
public <T> T[] toArray(T[] array)
private java.util.List<E> snapshot()
public int add(E element, int occurrences)
add in interface Multiset<E>add in class AbstractMultiset<E>element - the element to addoccurrences - the number of occurrences to addjava.lang.IllegalArgumentException - if occurrences is negative, or if
the resulting amount would exceed Integer.MAX_VALUEpublic int remove(@Nullable
java.lang.Object element,
int occurrences)
remove in interface Multiset<E>remove in class AbstractMultiset<E>element - the element whose occurrences should be removedoccurrences - the number of occurrences of the element to removejava.lang.IllegalArgumentException - if occurrences is negativepublic boolean removeExactly(@Nullable
java.lang.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)java.lang.IllegalArgumentException - if occurrences is negativepublic int setCount(E element, int count)
element such that the count(java.lang.Object) of the
element becomes count.setCount in interface Multiset<E>setCount in class AbstractMultiset<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 calljava.lang.IllegalArgumentException - if count is negativepublic 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>setCount in class AbstractMultiset<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.java.lang.IllegalArgumentException - if expectedOldCount or newCount is negativejava.util.Set<E> createElementSet()
AbstractMultisetAbstractMultiset.elementSet().createElementSet in class AbstractMultiset<E>public java.util.Set<Multiset.Entry<E>> createEntrySet()
createEntrySet in class AbstractMultiset<E>int distinctElements()
distinctElements in class AbstractMultiset<E>public boolean isEmpty()
isEmpty in interface java.util.Collection<E>isEmpty in class AbstractMultiset<E>java.util.Iterator<Multiset.Entry<E>> entryIterator()
entryIterator in class AbstractMultiset<E>public void clear()
clear in interface java.util.Collection<E>clear in class AbstractMultiset<E>private void writeObject(java.io.ObjectOutputStream stream)
throws java.io.IOException
java.io.IOExceptionprivate void readObject(java.io.ObjectInputStream stream)
throws java.io.IOException,
java.lang.ClassNotFoundException
java.io.IOExceptionjava.lang.ClassNotFoundException