javadoc.com.google.common.collect.ConcurrentHashMultiset.html Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of guava-osgi

Repackaging of Google Guava libraries as OSGi bundle

The newest version!








ConcurrentHashMultiset (Guava: Google Core Libraries for Java 11.0.1 API)























  
      Overview 
      Package 
    Class 
      Use 
      Tree 
      Deprecated 
      Index 
      Help 
  









 PREV CLASS 
 NEXT CLASS

  FRAMES   
 NO FRAMES   
 







  SUMMARY: NESTED | FIELD | CONSTR | METHOD

DETAIL: FIELD | CONSTR | METHOD









com.google.common.collect


Class ConcurrentHashMultiset<E>
java.lang.Object
  java.util.AbstractCollection<E>
      com.google.common.collect.ConcurrentHashMultiset<E>


All Implemented Interfaces: 
Multiset<E>, Serializable, Iterable<E>, Collection<E>



public final class ConcurrentHashMultiset<E>extends AbstractCollection<E>
implements Serializable




A multiset that supports concurrent modifications and that provides atomic versions of most
 Multiset operations (exceptions where noted). Null elements are not supported.




Since:
  2.0 (imported from Google Collections Library)
Author:
  Cliff L. Biffle, mike nonemacher
See Also:
Serialized Form









Nested Class Summary


 


Nested classes/interfaces inherited from interface com.google.common.collect.Multiset


Multiset.Entry<E>


 







Method Summary



 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(Object element)



          Determines whether this multiset contains the specified element.



 int
count(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(GenericMapMaker<? super E,? super Number> mapMaker)



          Creates a new, empty ConcurrentHashMultiset using mapMaker
 to construct 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<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(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(Object element)



          Removes a single occurrence of the specified element from this
 multiset, if present.



 int
remove(Object element,
             int occurrences)



          Removes a number of occurrences of the specified element from this multiset.



 boolean
removeAll(Collection<?> elementsToRemove)



          



 boolean
removeExactly(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()



          



 Object[]
toArray()



           







<T> T[]



toArray(T[] array)



           



 String
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 com.google.common.collect.Multiset


containsAll


 








Method Detail




create
public static <E> ConcurrentHashMultiset<E> create()

Creates a new, empty ConcurrentHashMultiset using the default
 initial capacity, load factor, and concurrency settings.











create
public 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.

 This implementation is highly efficient when elements is itself a Multiset.





Parameters:
elements - the elements that the multiset should contain





create
@Beta
public static <E> ConcurrentHashMultiset<E> create(GenericMapMaker<? super E,? super Number> mapMaker)

Creates a new, empty 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(long, java.util.concurrent.TimeUnit) makes sense (evict the entry that
 was queried or updated longest ago), but MapMaker.expireAfterWrite(long, java.util.concurrent.TimeUnit) 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.





Since:
  7.0






count
public int count(@Nullable
                 Object element)

Returns the number of occurrences of element in this multiset.


Specified by:
count in interface Multiset<E>


Parameters:
element - the element to look for
Returns:
the nonnegative number of occurrences of the element





size
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.


Specified by:
size in interface Collection<E>








toArray
public Object[] toArray()


Specified by:
toArray in interface Collection<E>
Overrides:
toArray in class AbstractCollection<E>








toArray
public <T> T[] toArray(T[] array)


Specified by:
toArray in interface Collection<E>
Overrides:
toArray in class AbstractCollection<E>








add
public int add(E element,
               int occurrences)

Adds a number of occurrences of the specified element to this multiset.


Specified by:
add in interface Multiset<E>


Parameters:
element - the element to add
occurrences - the number of occurrences to add
Returns:
the previous count of the element before the operation; possibly zero
Throws:
IllegalArgumentException - if occurrences is negative, or if
     the resulting amount would exceed Integer.MAX_VALUE





remove
public int remove(@Nullable
                  Object element,
                  int occurrences)

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 interface Multiset<E>


Parameters:
element - the element whose occurrences should be removed
occurrences - the number of occurrences of the element to remove
Returns:
the count of the element before the operation; possibly zero
Throws:
IllegalArgumentException - if occurrences is negative





removeExactly
public 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.

 This method, in contrast to remove(Object, int), has no effect when the
 element count is smaller than occurrences.





Parameters:
element - the element to remove
occurrences - the number of occurrences of element to remove
Returns:
true if the removal was possible (including if occurrences is zero)





setCount
public int setCount(E element,
                    int count)

Adds or removes occurrences of element such that the count(java.lang.Object) of the
 element becomes count.


Specified by:
setCount in interface Multiset<E>


Parameters:
element - the element to add or remove occurrences of; may be null
     only if explicitly allowed by the implementation
count - the desired count of the element in this multiset
Returns:
the count of element in the multiset before this call
Throws:
IllegalArgumentException - if count is negative





setCount
public 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. If element does not appear
 in the multiset exactly expectedOldCount times, no changes will be made.


Specified by:
setCount in interface Multiset<E>


Parameters:
element - the element to conditionally set the count of; may be null
     only if explicitly allowed by the implementation
expectedOldCount - the expected present count of the element in this multiset
newCount - 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 that
     expectedOldCount == newCount, the method will return true if
     the condition was met.
Throws:
IllegalArgumentException - if expectedOldCount or newCount is negative





entrySet
public Set<Multiset.Entry<E>> entrySet()

Description copied from interface: Multiset
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. 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.


Specified by:
entrySet in interface Multiset<E>



Returns:
a set of entries representing the data of this multiset





isEmpty
public boolean isEmpty()


Specified by:
isEmpty in interface Collection<E>








clear
public void clear()


Specified by:
clear in interface Collection<E>








contains
public boolean contains(@Nullable
                        Object element)

Description copied from interface: Multiset
Determines whether this multiset contains the specified element.

 This 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.


Specified by:
contains in interface Multiset<E>
Specified by:
contains in interface Collection<E>
Overrides:
contains in class AbstractCollection<E>


Parameters:
element - the element to check for
Returns:
true if this multiset contains at least one occurrence of
     the element





iterator
public Iterator<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.


Specified by:
iterator in interface Multiset<E>
Specified by:
iterator in interface Iterable<E>
Specified by:
iterator in interface Collection<E>
Specified by:
iterator in class AbstractCollection<E>








add
public boolean add(@Nullable
                   E element)

Description copied from interface: Multiset
Adds a single occurrence of the specified element to this multiset.

 This 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.


Specified by:
add in interface Multiset<E>
Specified by:
add in interface Collection<E>
Overrides:
add in class AbstractCollection<E>


Parameters:
element - the element to add one occurrence of; may be null only if
     explicitly allowed by the implementation
Returns:
true always, since this call is required to modify the
     multiset, unlike other Collection types





remove
public boolean remove(Object element)

Description copied from interface: Multiset
Removes a single occurrence of the specified element from this
 multiset, if present.

 This 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.


Specified by:
remove in interface Multiset<E>
Specified by:
remove in interface Collection<E>
Overrides:
remove in class AbstractCollection<E>


Parameters:
element - the element to remove one occurrence of
Returns:
true if an occurrence was found and removed





addAll
public boolean addAll(Collection<? extends E> elementsToAdd)


 
 This implementation is highly efficient when elementsToAdd
 is itself a Multiset.


Specified by:
addAll in interface Collection<E>
Overrides:
addAll in class AbstractCollection<E>








removeAll
public boolean removeAll(Collection<?> elementsToRemove)

Description copied from interface: Multiset


 Note: 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.


Specified by:
removeAll in interface Multiset<E>
Specified by:
removeAll in interface Collection<E>
Overrides:
removeAll in class AbstractCollection<E>








retainAll
public boolean retainAll(Collection<?> elementsToRetain)

Description copied from interface: Multiset


 Note: 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.


Specified by:
retainAll in interface Multiset<E>
Specified by:
retainAll in interface Collection<E>
Overrides:
retainAll in class AbstractCollection<E>


See Also:
Multisets.retainOccurrences(Multiset, Multiset)





elementSet
public Set<E> elementSet()

Description copied from interface: Multiset
Returns the set of distinct elements contained in this multiset. The
 element set is backed by the same data as the multiset, so any change to
 either is immediately reflected in the other. The order of the elements in
 the element set is unspecified.

 If 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().


Specified by:
elementSet in interface Multiset<E>



Returns:
a view of the set of distinct elements in this multiset





equals
public boolean equals(@Nullable
                      Object object)

Compares the specified object with this multiset for equality. Returns
 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.


Specified by:
equals in interface Multiset<E>
Specified by:
equals in interface Collection<E>
Overrides:
equals in class Object








hashCode
public int hashCode()

Returns the hash code for this multiset. This is defined as the sum of
    ((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().


Specified by:
hashCode in interface Multiset<E>
Specified by:
hashCode in interface Collection<E>
Overrides:
hashCode in class Object








toString
public 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().


Specified by:
toString in interface Multiset<E>
Overrides:
toString in class AbstractCollection<E>

















  
      Overview 
      Package 
    Class 
      Use 
      Tree 
      Deprecated 
      Index 
      Help 
  









 PREV CLASS 
 NEXT CLASS

  FRAMES   
 NO FRAMES   
 







  SUMMARY: NESTED | FIELD | CONSTR | METHOD

DETAIL: FIELD | CONSTR | METHOD






Copyright © 2010-2012. All Rights Reserved.

javadoc.com.google.common.collect.ConcurrentHashMultiset.html Maven / Gradle / Ivy

com.google.common.collect Class ConcurrentHashMultiset<E>

create

create

create

count

size

toArray

toArray

add

remove

removeExactly

setCount

setCount

entrySet

isEmpty

clear

contains

iterator

add

remove

addAll

removeAll

retainAll

elementSet

equals

hashCode

toString

com.google.common.collect
Class ConcurrentHashMultiset<E>