@GwtCompatible(emulated=true) public final class TreeMultiset<E> extends AbstractCollection<E> implements Serializable
Comparator
. In all cases, this implementation uses
Comparable.compareTo(T)
or
Comparator.compare(T, T)
instead of
Object.equals(java.lang.Object)
to determine equivalence of instances.
Warning: The comparison must be consistent with equals as explained by the Comparable
class specification. Otherwise, the resulting multiset will violate the Collection
contract, which is specified in terms of Object
.
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 an element to this multiset.
|
boolean |
addAll(Collection
|
void |
clear()
|
Comparator |
comparator()
Returns the comparator that orders this multiset, or
Ordering if the natural ordering of the elements is used.
|
boolean |
contains(Object
Determines whether this multiset contains the specified element.
|
int |
count(Object
Returns the number of occurrences of an element in this multiset (the
count of the element).
|
static <E extends Comparable |
create()
Creates a new, empty multiset, sorted according to the elements' natural order.
|
static <E> TreeMultiset |
create(Comparator
Creates a new, empty multiset, sorted according to the specified comparator.
|
static <E extends Comparable |
create(Iterable
Creates an empty multiset containing the given initial elements, sorted according to the elements' natural order.
|
SortedMultiset |
descendingMultiset()
Returns a descending view of this multiset.
|
NavigableSet |
elementSet()
Returns the set of distinct elements contained in this multiset.
|
Set |
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
Compares the specified object with this multiset for equality.
|
Multiset |
firstEntry()
Returns the entry of the first element in this multiset, or
null if this multiset is empty.
|
int |
hashCode()
Returns the hash code for this multiset.
|
SortedMultiset |
headMultiset(E upperBound, BoundType
Returns a view of this multiset restricted to the elements less than
upperBound , optionally including
upperBound itself.
|
boolean |
isEmpty()
|
Iterator |
iterator()
|
Multiset |
lastEntry()
Returns the entry of the last element in this multiset, or
null if this multiset is empty.
|
Multiset |
pollFirstEntry()
Returns and removes the entry associated with the lowest element in this multiset, or returns
null if this multiset is empty.
|
Multiset |
pollLastEntry()
Returns and removes the entry associated with the greatest element in this multiset, or returns
null if this multiset is empty.
|
boolean |
remove(Object
Removes a
single occurrence of the specified element from this multiset, if present.
|
int |
remove(Object
Removes a number of occurrences of the specified element from this multiset.
|
boolean |
removeAll(Collection
|
boolean |
retainAll(Collection
|
int |
setCount(E element, int count)
Adds or removes the necessary occurrences of an element such that the element attains the desired count.
|
boolean |
setCount(E element, int oldCount, int newCount)
Conditionally sets the count of an element to a new value, as described in
Multiset , provided that the element has the expected current count.
|
int |
size()
|
SortedMultiset |
subMultiset(E fromElement, BoundType
Returns a view of this multiset restricted to the range between
lowerBound and
upperBound .
|
SortedMultiset |
tailMultiset(E lowerBound, BoundType
Returns a view of this multiset restricted to the elements greater than
lowerBound , optionally including
lowerBound itself.
|
String |
toString()
|
containsAll, toArray, toArray
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
entrySet, iterator
add, contains, containsAll, equals, hashCode, remove, removeAll, retainAll, toString
addAll, clear, isEmpty, parallelStream, removeIf, spliterator, stream, toArray, toArray
public static <E extends Comparable> TreeMultiset <E> create()
Comparable
interface. Furthermore, all such elements must be
mutually comparable:
e1.compareTo(e2)
must not throw a
ClassCastException
for any elements
e1
and
e2
in the multiset. If the user attempts to add an element to the multiset that violates this constraint (for example, the user attempts to add a string element to a set whose elements are integers), the
add(Object)
call will throw a
ClassCastException
.
The type specification is <E extends Comparable>
, instead of the more specific <E extends Comparable<? super E>>
, to support classes defined without generics.
public static <E> TreeMultiset<E> create(Comparator <? super E> comparator)
comparator.compare(e1, e2)
must not throw a
ClassCastException
for any elements
e1
and
e2
in the multiset. If the user attempts to add an element to the multiset that violates this constraint, the
add(Object)
call will throw a
ClassCastException
.
comparator
- the comparator that will be used to sort this multiset. A null value indicates that the elements'
natural ordering should be used.
public static <E extends Comparable> TreeMultiset <E> create(Iterable <? extends E> elements)
This implementation is highly efficient when elements
is itself a Multiset
.
The type specification is <E extends Comparable>
, instead of the more specific <E extends Comparable<? super E>>
, to support classes defined without generics.
public int size()
public int count(Objectelement)
Multiset
Object.equals(java.lang.Object)
-based multiset, this gives the same result as
Collections.frequency(java.util.Collection<?>, java.lang.Object)
(which would presumably perform more poorly).
Note: the utility method Iterables
generalizes this operation; it correctly delegates to this method when dealing with a multiset, but it can also accept any other iterable type.
public int add(E element, int occurrences)
Multiset
occurrences == 1
, this method has the identical effect to
Multiset.add(Object)
. This method is functionally equivalent (except in the case of overflow) to the call
addAll(Collections.nCopies(element, occurrences))
, which would presumably perform much more poorly.
add
in interface
Multiset<E>
element
- the element to add occurrences of; may be null only if explicitly allowed by the implementation
occurrences
- the number of occurrences of the element to add. May be zero, in which case no change will be made.
public int remove(Objectelement, int occurrences)
Multiset
occurrences == 1
, this is functionally equivalent to the call
remove(element)
.
remove
in interface
Multiset<E>
element
- the element to conditionally remove occurrences of
occurrences
- the number of occurrences of the element to remove. May be zero, in which case no change will be made.
public int setCount(E element, int count)
Multiset
setCount
in interface
Multiset<E>
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
public boolean setCount(E element, int oldCount, int newCount)
Multiset
Multiset.setCount(Object, int)
, provided that the element has the expected current count. If the current count is not
oldCount
, no change is made.
setCount
in interface
Multiset<E>
element
- the element to conditionally set the count of; may be null only if explicitly allowed by the implementation
oldCount
- the expected present count of the element in this multiset
newCount
- the desired count of the element in this multiset
true
if the condition for modification was met. This implies that the multiset was indeed modified, unless
oldCount == newCount
.
public SortedMultiset<E> headMultiset(E upperBound, BoundType boundType)
SortedMultiset
upperBound
, optionally including
upperBound
itself. The returned multiset is a view of this multiset, so changes to one will be reflected in the other. The returned multiset supports all operations that this multiset supports.
The returned multiset will throw an IllegalArgumentException
on attempts to add elements outside its range.
public SortedMultiset<E> tailMultiset(E lowerBound, BoundType boundType)
SortedMultiset
lowerBound
, optionally including
lowerBound
itself. The returned multiset is a view of this multiset, so changes to one will be reflected in the other. The returned multiset supports all operations that this multiset supports.
The returned multiset will throw an IllegalArgumentException
on attempts to add elements outside its range.
public NavigableSet<E> elementSet()
Multiset
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()
.
elementSet
in interface
Multiset<E>
elementSet
in interface
SortedMultiset<E>
public Comparator<? super E> comparator()
SortedMultiset
Ordering.natural()
if the natural ordering of the elements is used.
public Multiset.Entry <E> firstEntry()
SortedMultiset
null
if this multiset is empty.
public Multiset.Entry <E> lastEntry()
SortedMultiset
null
if this multiset is empty.
public Multiset.Entry <E> pollFirstEntry()
SortedMultiset
null
if this multiset is empty.
public Multiset.Entry <E> pollLastEntry()
SortedMultiset
null
if this multiset is empty.
public SortedMultiset<E> subMultiset(E fromElement, BoundType fromBoundType, E toElement, BoundType toBoundType)
SortedMultiset
lowerBound
and
upperBound
. The returned multiset is a view of this multiset, so changes to one will be reflected in the other. The returned multiset supports all operations that this multiset supports.
The returned multiset will throw an IllegalArgumentException
on attempts to add elements outside its range.
This method is equivalent to tailMultiset(lowerBound, lowerBoundType).headMultiset(upperBound, upperBoundType)
.
public SortedMultiset<E> descendingMultiset()
SortedMultiset
public boolean isEmpty()
public boolean contains(Objectelement)
Multiset
This method refines Collection
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 for
true
if this multiset contains at least one occurrence of the element
public Iterator<E> iterator()
Multiset
Elements that occur multiple times in the multiset will appear multiple times in this iterator, though not necessarily sequentially.
public boolean add(E element)
Multiset
This method refines Collection
, 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 implementation
true
always, since this call is required to modify the multiset, unlike other
Collection
types
public boolean remove(Objectelement)
Multiset
This method refines Collection
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 of
true
if an occurrence was found and removed
public boolean addAll(Collection<? extends E> elementsToAdd)
This implementation is highly efficient when elementsToAdd
is itself a Multiset
.
public boolean removeAll(Collection<?> elementsToRemove)
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
.
This method refines Collection
to further specify that it may not throw an exception in response to any of elements
being null or of the wrong type.
public boolean retainAll(Collection<?> elementsToRetain)
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
.
This method refines 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 void clear()
public Set<Multiset .Entry <E>> entrySet()
Multiset
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.
public boolean equals(Objectobject)
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 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
.
public StringtoString()
It is recommended, though not mandatory, that this method return the result of invoking Multiset
on the Multiset
, yielding a result such as [a x 3, c, d x 2, e]
.
This implementation returns the result of invoking toString
on Multiset
.