@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.equals(java.lang.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<? extends E> elementsToAdd) |
void |
clear() |
Comparator<? super E> |
comparator()
Returns the comparator that orders this multiset, or
Ordering.natural() if the natural ordering of the elements is used. |
boolean |
contains(Object element)
Determines whether this multiset contains the specified element.
|
int |
count(Object element)
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<E> |
create(Comparator<? super E> comparator)
Creates a new, empty multiset, sorted according to the specified comparator.
|
static <E extends Comparable> |
create(Iterable<? extends E> elements)
Creates an empty multiset containing the given initial elements, sorted according to the
elements' natural order.
|
SortedMultiset<E> |
descendingMultiset()
Returns a descending view of this multiset.
|
NavigableSet<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.
|
Multiset.Entry<E> |
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<E> |
headMultiset(E upperBound,
BoundType boundType)
Returns a view of this multiset restricted to the elements less than
upperBound , optionally including upperBound itself. |
boolean |
isEmpty() |
Iterator<E> |
iterator() |
Multiset.Entry<E> |
lastEntry()
Returns the entry of the last element in this multiset, or
null if
this multiset is empty. |
Multiset.Entry<E> |
pollFirstEntry()
Returns and removes the entry associated with the lowest element in this
multiset, or returns
null if this multiset is empty. |
Multiset.Entry<E> |
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 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 |
retainAll(Collection<?> elementsToRetain) |
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.setCount(Object, int) , provided that the element has the expected
current count. |
int |
size()
Returns the total number of all occurrences of all elements in this multiset.
|
SortedMultiset<E> |
subMultiset(E fromElement,
BoundType fromBoundType,
E toElement,
BoundType toBoundType)
Returns a view of this multiset restricted to the range between
lowerBound and upperBound . |
SortedMultiset<E> |
tailMultiset(E lowerBound,
BoundType 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, forEach, forEachEntry, hashCode, remove, removeAll, retainAll, spliterator, toString
addAll, clear, isEmpty, parallelStream, removeIf, 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(@Nullable 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()
Multiset
Note: this method does not return the number of distinct elements in the
multiset, which is given by entrySet().size()
.
public int count(@Nullable Object element)
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.frequency(java.lang.Iterable<?>, java.lang.Object)
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(@Nullable 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 implementationoccurrences
- the number of occurrences of the element to add. May be
zero, in which case no change will be made.public int remove(@Nullable Object element, 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 ofoccurrences
- the number of occurrences of the element to remove. May be zero, in which
case no change will be made.public int setCount(@Nullable 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 implementationcount
- the desired count of the element in this multisetpublic boolean setCount(@Nullable 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 implementationoldCount
- the expected present count of the element in this multisetnewCount
- the desired count of the element in this multisettrue
if the condition for modification was met. This
implies that the multiset was indeed modified, unless
oldCount == newCount
.public SortedMultiset<E> headMultiset(@Nullable 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.
headMultiset
in interface SortedMultiset<E>
public SortedMultiset<E> tailMultiset(@Nullable 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.
tailMultiset
in interface SortedMultiset<E>
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.comparator
in interface SortedMultiset<E>
public Multiset.Entry<E> firstEntry()
SortedMultiset
null
if
this multiset is empty.firstEntry
in interface SortedMultiset<E>
public Multiset.Entry<E> lastEntry()
SortedMultiset
null
if
this multiset is empty.lastEntry
in interface SortedMultiset<E>
public Multiset.Entry<E> pollFirstEntry()
SortedMultiset
null
if this multiset is empty.pollFirstEntry
in interface SortedMultiset<E>
public Multiset.Entry<E> pollLastEntry()
SortedMultiset
null
if this multiset is empty.pollLastEntry
in interface SortedMultiset<E>
public SortedMultiset<E> subMultiset(@Nullable E fromElement, BoundType fromBoundType, @Nullable 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)
.
subMultiset
in interface SortedMultiset<E>
public SortedMultiset<E> descendingMultiset()
SortedMultiset
descendingMultiset
in interface SortedMultiset<E>
public boolean isEmpty()
isEmpty
in interface Collection<E>
isEmpty
in class AbstractCollection<E>
public boolean contains(@Nullable Object element)
Multiset
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.
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 elementpublic Iterator<E> iterator()
Multiset
Elements that occur multiple times in the multiset will appear multiple times in this iterator, though not necessarily sequentially.
iterator
in interface Multiset<E>
iterator
in interface Iterable<E>
iterator
in interface Collection<E>
iterator
in class AbstractCollection<E>
public boolean add(@Nullable E element)
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.
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
typespublic boolean remove(@Nullable Object element)
Multiset
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.
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 removedpublic 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>
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.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>
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.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 void clear()
clear
in interface Collection<E>
clear
in class AbstractCollection<E>
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(@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 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 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>
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