Class PriorityQueue<T>

java.lang.Object

io.vavr.collection.AbstractQueue<T, PriorityQueue<T>>

io.vavr.collection.PriorityQueue<T>

All Implemented Interfaces:

Foldable<T>, Ordered<T>, Traversable<T>, Value<T>, Serializable, Iterable<T>

public final class PriorityQueue<T>
extends AbstractQueue<T, PriorityQueue<T>>
implements Serializable, Ordered<T>

A PriorityQueue.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private final Comparator<? super T>	comparator
private final Seq<PriorityQueueBase.Node<T>>	forest
private static final long	serialVersionUID
private final int	size

Constructor Summary

Constructors

Modifier	Constructor	Description
private	PriorityQueue(Comparator<? super T> comparator, Seq<PriorityQueueBase.Node<T>> forest, int size)

Method Summary

Modifier and Type	Method	Description
<R> PriorityQueue<R>	collect(PartialFunction<? super T, ? extends R> partialFunction)	Collects all elements that are in the domain of the given partialFunction by mapping the elements to type R.
static <T> Collector<T, ArrayList<T>, PriorityQueue<T>>	collector()	Returns a Collector which may be used in conjunction with Stream.collect(Collector) to obtain a PriorityQueue<T>.
Comparator<T>	comparator()	Returns the comparator which defines the order of the elements contained in this collection.
Tuple2<T, PriorityQueue<T>>	dequeue()	Removes an element from this Queue.
PriorityQueue<T>	distinct()	Returns a new version of this which contains no duplicates.
PriorityQueue<T>	distinctBy(Comparator<? super T> comparator)	Returns a new version of this which contains no duplicates.
<U> PriorityQueue<T>	distinctBy(Function<? super T, ? extends U> keyExtractor)	Returns a new version of this which contains no duplicates.
PriorityQueue<T>	drop(int n)	Drops the first n elements of this or all elements, if this length < n.
PriorityQueue<T>	dropRight(int n)	Drops the last n elements of this or all elements, if this length < n.
PriorityQueue<T>	dropWhile(Predicate<? super T> predicate)	Drops elements while the predicate holds for the current element.
static <T extends Comparable<? super T>> PriorityQueue<T>	empty()	Returns the empty PriorityQueue.
static <T> PriorityQueue<T>	empty(Comparator<? super T> comparator)
PriorityQueue<T>	enqueue(T element)	Enqueues a new element.
PriorityQueue<T>	enqueueAll(Iterable<? extends T> elements)	Enqueues the given elements.
boolean	equals(Object o)	In Vavr there are four basic classes of collections: Seq (sequential elements) Set (distinct elements) Map (indexed elements) Multimap (indexed collections) Two collection instances of these classes are equal if and only if both collections belong to the same basic collection class (Seq, Set, Map or Multimap) contain the same elements have the same element order, if the collections are of type Seq Two Map/Multimap elements, resp.
static <T> PriorityQueue<T>	fill(int size, Supplier<? extends T> supplier)	Returns a PriorityQueue containing size values supplied by a given Supplier supplier.
static <T> PriorityQueue<T>	fill(int size, T element)	Returns a PriorityQueue containing n times the given element
PriorityQueue<T>	filter(Predicate<? super T> predicate)	Returns a new traversable consisting of all elements which satisfy the given predicate.
<U> PriorityQueue<U>	flatMap(Comparator<U> comparator, Function<? super T, ? extends Iterable<? extends U>> mapper)
<U> PriorityQueue<U>	flatMap(Function<? super T, ? extends Iterable<? extends U>> mapper)	FlatMaps this Traversable.
<U> U	foldRight(U zero, BiFunction<? super T, ? super U, ? extends U> accumulator)	Accumulates the elements of this PriorityQueue by successively calling the given function f from the right, starting with a value zero of type B.
<C> Map<C, ? extends PriorityQueue<T>>	groupBy(Function<? super T, ? extends C> classifier)	Groups this elements by classifying the elements.
Iterator<? extends PriorityQueue<T>>	grouped(int size)	Groups this Traversable into fixed size blocks.
boolean	hasDefiniteSize()	Checks if this PriorityQueue is known to have a finite size.
int	hashCode()	Returns the hash code of this collection.
T	head()	Returns the first element of a non-empty PriorityQueue.
PriorityQueue<T>	init()	Dual of tail(), returning all elements except the last.
boolean	isAsync()	A PriorityQueue is computed synchronously.
boolean	isEmpty()	Checks if this Traversable is empty.
boolean	isLazy()	A PriorityQueue is computed eagerly.
boolean	isOrdered()	Checks if this Traversable is ordered
boolean	isTraversableAgain()	Checks if this PriorityQueue can be repeatedly traversed.
T	last()	Dual of Traversable.head(), returning the last element.
int	length()	Computes the number of elements of this PriorityQueue.
<U> PriorityQueue<U>	map(Comparator<U> comparator, Function<? super T, ? extends U> mapper)
<U> PriorityQueue<U>	map(Function<? super T, ? extends U> mapper)	Maps the elements of this Traversable to elements of a new type preserving their order, if any.
PriorityQueue<T>	merge(PriorityQueue<T> target)
static <T> PriorityQueue<T>	narrow(PriorityQueue<? extends T> queue)	Narrows a widened PriorityQueue<? extends T> to PriorityQueue<T> by performing a type-safe cast.
static <T> PriorityQueue<T>	of(Comparator<? super T> comparator, T element)
static <T> PriorityQueue<T>	of(Comparator<? super T> comparator, T... elements)
static <T extends Comparable<? super T>> PriorityQueue<T>	of(T element)
static <T extends Comparable<? super T>> PriorityQueue<T>	of(T... elements)
static <T extends Comparable<? super T>> PriorityQueue<T>	ofAll(Iterable<? extends T> elements)
static <T> PriorityQueue<T>	ofAll(Comparator<? super T> comparator, Iterable<? extends T> elements)
static <T> PriorityQueue<T>	ofAll(Comparator<? super T> comparator, Stream<? extends T> javaStream)
static <T extends Comparable<? super T>> PriorityQueue<T>	ofAll(Stream<? extends T> javaStream)
PriorityQueue<T>	orElse(Iterable<? extends T> other)	Returns this PriorityQueue if it is nonempty, otherwise PriorityQueue created from iterable, using existing comparator.
PriorityQueue<T>	orElse(Supplier<? extends Iterable<? extends T>> supplier)	Returns this PriorityQueue if it is nonempty, otherwise PriorityQueue created from result of evaluating supplier, using existing comparator.
Tuple2<? extends PriorityQueue<T>, ? extends PriorityQueue<T>>	partition(Predicate<? super T> predicate)	Creates a partition of this Traversable by splitting this elements in two in distinct traversables according to a predicate.
PriorityQueue<T>	replace(T currentElement, T newElement)	Replaces the first occurrence (if exists) of the given currentElement with newElement.
PriorityQueue<T>	replaceAll(T currentElement, T newElement)	Replaces all occurrences of the given currentElement with newElement.
PriorityQueue<T>	scan(T zero, BiFunction<? super T, ? super T, ? extends T> operation)	Computes a prefix scan of the elements of the collection.
<U> PriorityQueue<U>	scanLeft(U zero, BiFunction<? super U, ? super T, ? extends U> operation)	Produces a collection containing cumulative results of applying the operator going left to right.
<U> PriorityQueue<U>	scanRight(U zero, BiFunction<? super T, ? super U, ? extends U> operation)	Produces a collection containing cumulative results of applying the operator going right to left.
Iterator<? extends PriorityQueue<T>>	slideBy(Function<? super T, ?> classifier)	Slides a non-overlapping window of a variable size over this Traversable.
Iterator<? extends PriorityQueue<T>>	sliding(int size)	Slides a window of a specific size and step size 1 over this Traversable by calling Traversable.sliding(int, int).
Iterator<? extends PriorityQueue<T>>	sliding(int size, int step)	Slides a window of a specific size and step size over this Traversable.
Tuple2<? extends PriorityQueue<T>, ? extends PriorityQueue<T>>	span(Predicate<? super T> predicate)	Returns a tuple where the first element is the longest prefix of elements that satisfy the given predicate and the second element is the remainder.
String	stringPrefix()	Returns the name of this Value type, which is used by toString().
static <T> PriorityQueue<T>	tabulate(int size, Function<? super Integer, ? extends T> function)	Returns a PriorityQueue containing size values of a given Function function over a range of integer values from 0 to size - 1.
PriorityQueue<T>	tail()	Drops the first element of a non-empty PriorityQueue.
PriorityQueue<T>	take(int n)	Takes the first n elements of this or all elements, if this length < n.
PriorityQueue<T>	takeRight(int n)	Takes the last n elements of this or all elements, if this length < n.
PriorityQueue<T>	takeUntil(Predicate<? super T> predicate)	Takes elements until the predicate holds for the current element.
List<T>	toList()	Converts this to a List.
<T1,T2> Tuple2<? extends PriorityQueue<T1>, ? extends PriorityQueue<T2>>	unzip(Function<? super T, Tuple2<? extends T1, ? extends T2>> unzipper)	Unzips this elements by mapping this elements to pairs which are subsequently split into two distinct sets.
<T1,T2,T3> Tuple3<? extends PriorityQueue<T1>, ? extends PriorityQueue<T2>, ? extends PriorityQueue<T3>>	unzip3(Function<? super T, Tuple3<? extends T1, ? extends T2, ? extends T3>> unzipper)	Unzips this elements by mapping this elements to triples which are subsequently split into three distinct sets.
private PriorityQueue<T>	with(Seq<PriorityQueueBase.Node<T>> forest, int size)
<U> PriorityQueue<Tuple2<T,U>>	zip(Iterable<? extends U> that)	Returns a traversable formed from this traversable and another Iterable collection by combining corresponding elements in pairs.
<U> PriorityQueue<Tuple2<T,U>>	zipAll(Iterable<? extends U> that, T thisElem, U thatElem)	Returns a traversable formed from this traversable and another Iterable by combining corresponding elements in pairs.
<U,R> PriorityQueue<R>	zipWith(Iterable<? extends U> that, BiFunction<? super T, ? super U, ? extends R> mapper)	Returns a traversable formed from this traversable and another Iterable collection by mapping elements.
PriorityQueue<Tuple2<T,Integer>>	zipWithIndex()	Zips this traversable with its indices.
<U> PriorityQueue<U>	zipWithIndex(BiFunction<? super T, ? super Integer, ? extends U> mapper)	Zips this traversable with its indices by applying mapper provided.

Methods inherited from class AbstractQueue

dequeueOption, dropUntil, enqueue, initOption, peek, peek, peekOption, reject, removeAll, removeAll, retainAll, tailOption, takeWhile, toString

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface Foldable

fold, reduce, reduceOption

Methods inherited from interface Traversable

arrangeBy, average, containsAll, count, existsUnique, find, findLast, foldLeft, forEachWithIndex, get, headOption, isDistinct, isSequential, isSingleValued, iterator, lastOption, max, maxBy, maxBy, min, minBy, minBy, mkCharSeq, mkCharSeq, mkCharSeq, mkString, mkString, mkString, nonEmpty, product, reduceLeft, reduceLeftOption, reduceRight, reduceRightOption, single, singleOption, size, spliterator, sum

Methods inherited from interface Value

collect, collect, contains, corresponds, eq, exists, forAll, forEach, getOrElse, getOrElse, getOrElseThrow, getOrElseTry, getOrNull, out, out, stderr, stdout, toArray, toCharSeq, toCompletableFuture, toEither, toEither, toInvalid, toInvalid, toJavaArray, toJavaArray, toJavaArray, toJavaCollection, toJavaList, toJavaList, toJavaMap, toJavaMap, toJavaMap, toJavaOptional, toJavaParallelStream, toJavaSet, toJavaSet, toJavaStream, toLeft, toLeft, toLinkedMap, toLinkedMap, toLinkedSet, toMap, toMap, toOption, toPriorityQueue, toPriorityQueue, toQueue, toRight, toRight, toSet, toSortedMap, toSortedMap, toSortedMap, toSortedMap, toSortedSet, toSortedSet, toStream, toTree, toTree, toTry, toTry, toValid, toValid, toValidation, toValidation, toVector

Field Details

serialVersionUID

private static final long serialVersionUID

See Also:

• Constant Field Values

comparator

private final Comparator<? super T> comparator

forest

private final Seq<PriorityQueueBase.Node<T>> forest

size

private final int size

Constructor Details

PriorityQueue

private PriorityQueue(Comparator<? super T> comparator,
 Seq<PriorityQueueBase.Node<T>> forest,
 int size)

Method Details

with

private PriorityQueue<T> with(Seq<PriorityQueueBase.Node<T>> forest,
 int size)

collect

public <R> PriorityQueue<R> collect(PartialFunction<? super T, ? extends R> partialFunction)

Description copied from interface: Traversable

Collects all elements that are in the domain of the given partialFunction by mapping the elements to type R.

More specifically, for each of this elements in iteration order first it is checked

partialFunction.isDefinedAt(element)

If the elements makes it through that filter, the mapped instance is added to the result collection

R newElement = partialFunction.apply(element)

Note:If this Traversable is ordered (i.e. extends Ordered, the caller of collect has to ensure that the elements are comparable (i.e. extend Comparable).

Specified by:

collect in interface Traversable<T>

Type Parameters:

R - The new element type

Parameters:

partialFunction - A function that is not necessarily defined of all elements of this traversable.

Returns:

A new Traversable instance containing elements of type R

enqueue

public PriorityQueue<T> enqueue(T element)

Enqueues a new element.

Specified by:

enqueue in class AbstractQueue<T, PriorityQueue<T>>

Parameters:

element - The new element

Returns:

a new PriorityQueue instance, containing the new element

enqueueAll

public PriorityQueue<T> enqueueAll(Iterable<? extends T> elements)

Enqueues the given elements. A queue has FIFO order, i.e. the first of the given elements is the first which will be retrieved.

Specified by:

enqueueAll in class AbstractQueue<T, PriorityQueue<T>>

Parameters:

elements - An PriorityQueue of elements, may be empty

Returns:

a new PriorityQueue instance, containing the new elements

Throws:

NullPointerException - if elements is null

head

public T head()

Returns the first element of a non-empty PriorityQueue.

Specified by:

head in interface Traversable<T>

Returns:

The first element of this PriorityQueue.

Throws:

NoSuchElementException - if this is empty

tail

public PriorityQueue<T> tail()

Drops the first element of a non-empty PriorityQueue.

Specified by:

tail in interface Traversable<T>

Specified by:

tail in class AbstractQueue<T, PriorityQueue<T>>

Returns:

A new instance of PriorityQueue containing all elements except the first.

Throws:

UnsupportedOperationException - if this is empty

dequeue

public Tuple2<T, PriorityQueue<T>> dequeue()

Description copied from class: AbstractQueue

Removes an element from this Queue.

Overrides:

dequeue in class AbstractQueue<T, PriorityQueue<T>>

Returns:

a tuple containing the first element and the remaining elements of this Queue

merge

public PriorityQueue<T> merge(PriorityQueue<T> target)

isAsync

public boolean isAsync()

A PriorityQueue is computed synchronously.

Specified by:

isAsync in interface Value<T>

Returns:

false

isEmpty

public boolean isEmpty()

Description copied from interface: Traversable

Checks if this Traversable is empty.

Specified by:

isEmpty in interface Traversable<T>

Specified by:

isEmpty in interface Value<T>

Returns:

true, if this Traversable contains no elements, false otherwise.

isLazy

public boolean isLazy()

A PriorityQueue is computed eagerly.

Specified by:

isLazy in interface Value<T>

Returns:

false

isOrdered

public boolean isOrdered()

Description copied from interface: Traversable

Checks if this Traversable is ordered

Specified by:

isOrdered in interface Traversable<T>

Returns:

true, if this Traversable is ordered, false otherwise.

empty

public static <T extends Comparable<? super T>>
PriorityQueue<T> empty()

Returns the empty PriorityQueue.

Type Parameters:

T - Component type

Returns:

The empty PriorityQueue.

empty

public static <T> PriorityQueue<T> empty(Comparator<? super T> comparator)

collector

public static <T>
Collector<T, ArrayList<T>, PriorityQueue<T>> collector()

Returns a Collector which may be used in conjunction with Stream.collect(Collector) to obtain a PriorityQueue<T>.

Type Parameters:

T - Component type of the PriorityQueue.

Returns:

A PriorityQueue<T> Collector.

narrow

public static <T> PriorityQueue<T> narrow(PriorityQueue<? extends T> queue)

Narrows a widened PriorityQueue<? extends T> to PriorityQueue<T> by performing a type-safe cast. This is eligible because immutable/read-only collections are covariant.

Type Parameters:

T - Component type of the PriorityQueue.

Parameters:

queue - An PriorityQueue.

Returns:

the given PriorityQueue instance as narrowed type PriorityQueue<T>.

of

public static <T extends Comparable<? super T>>
PriorityQueue<T> of(T element)

of

public static <T extends Comparable<? super T>>
PriorityQueue<T> of(T... elements)

of

public static <T> PriorityQueue<T> of(Comparator<? super T> comparator,
 T element)

of

public static <T> PriorityQueue<T> of(Comparator<? super T> comparator,
 T... elements)

ofAll

public static <T extends Comparable<? super T>>
PriorityQueue<T> ofAll(Iterable<? extends T> elements)

ofAll

public static <T> PriorityQueue<T> ofAll(Comparator<? super T> comparator,
 Iterable<? extends T> elements)

ofAll

public static <T extends Comparable<? super T>>
PriorityQueue<T> ofAll(Stream<? extends T> javaStream)

ofAll

public static <T> PriorityQueue<T> ofAll(Comparator<? super T> comparator,
 Stream<? extends T> javaStream)

tabulate

@GwtIncompatible
public static <T> PriorityQueue<T> tabulate(int size,
 Function<? super Integer, ? extends T> function)

Returns a PriorityQueue containing size values of a given Function function over a range of integer values from 0 to size - 1.

Type Parameters:

T - Component type of the PriorityQueue

Parameters:

size - The number of elements in the PriorityQueue

function - The Function computing element values

Returns:

A PriorityQueue consisting of elements function(0),function(1), ..., function(size - 1)

Throws:

NullPointerException - if function is null

fill

@GwtIncompatible
public static <T> PriorityQueue<T> fill(int size,
 Supplier<? extends T> supplier)

Returns a PriorityQueue containing size values supplied by a given Supplier supplier.

Type Parameters:

T - Component type of the PriorityQueue

Parameters:

size - The number of elements in the PriorityQueue

supplier - The Supplier computing element values

Returns:

A PriorityQueue of size size, where each element contains the result supplied by supplier.

Throws:

NullPointerException - if supplier is null

fill

@GwtIncompatible
public static <T> PriorityQueue<T> fill(int size,
 T element)

Returns a PriorityQueue containing n times the given element

Type Parameters:

T - Component type of the PriorityQueue

Parameters:

size - The number of elements in the PriorityQueue

element - The element

Returns:

A PriorityQueue of size size, where each element is the given element.

toList

public List<T> toList()

Description copied from interface: Value

Converts this to a List.

Specified by:

toList in interface Value<T>

Returns:

A new List.

distinct

public PriorityQueue<T> distinct()

Description copied from interface: Traversable

Returns a new version of this which contains no duplicates. Elements are compared using equals.

Specified by:

distinct in interface Traversable<T>

Returns:

a new Traversable containing this elements without duplicates

distinctBy

public PriorityQueue<T> distinctBy(Comparator<? super T> comparator)

Description copied from interface: Traversable

Returns a new version of this which contains no duplicates. Elements are compared using the given comparator.

Specified by:

distinctBy in interface Traversable<T>

Parameters:

comparator - A comparator

Returns:

a new Traversable containing this elements without duplicates

distinctBy

public <U> PriorityQueue<T> distinctBy(Function<? super T, ? extends U> keyExtractor)

Description copied from interface: Traversable

Returns a new version of this which contains no duplicates. Elements mapped to keys which are compared using equals.

The elements of the result are determined in the order of their occurrence - first match wins.

Specified by:

distinctBy in interface Traversable<T>

Type Parameters:

U - key type

Parameters:

keyExtractor - A key extractor

Returns:

a new Traversable containing this elements without duplicates

drop

public PriorityQueue<T> drop(int n)

Description copied from interface: Traversable

Drops the first n elements of this or all elements, if this length < n.

Specified by:

drop in interface Traversable<T>

Parameters:

n - The number of elements to drop.

Returns:

a new instance consisting of all elements of this except the first n ones, or else the empty instance, if this has less than n elements.

dropRight

public PriorityQueue<T> dropRight(int n)

Description copied from interface: Traversable

Drops the last n elements of this or all elements, if this length < n.

Specified by:

dropRight in interface Traversable<T>

Parameters:

n - The number of elements to drop.

Returns:

a new instance consisting of all elements of this except the last n ones, or else the empty instance, if this has less than n elements.

dropWhile

public PriorityQueue<T> dropWhile(Predicate<? super T> predicate)

Description copied from interface: Traversable

Drops elements while the predicate holds for the current element.

Note: This is essentially the same as dropUntil(predicate.negate()). It is intended to be used with method references, which cannot be negated directly.

Specified by:

dropWhile in interface Traversable<T>

Specified by:

dropWhile in class AbstractQueue<T, PriorityQueue<T>>

Parameters:

predicate - A condition tested subsequently for this elements.

Returns:

a new instance consisting of all elements starting from the first one which does not satisfy the given predicate.

filter

public PriorityQueue<T> filter(Predicate<? super T> predicate)

Description copied from interface: Traversable

Returns a new traversable consisting of all elements which satisfy the given predicate.

Specified by:

filter in interface Traversable<T>

Parameters:

predicate - A predicate

Returns:

a new traversable

flatMap

public <U> PriorityQueue<U> flatMap(Function<? super T, ? extends Iterable<? extends U>> mapper)

Description copied from interface: Traversable

FlatMaps this Traversable.

Specified by:

flatMap in interface Traversable<T>

Type Parameters:

U - The resulting component type.

Parameters:

mapper - A mapper

Returns:

A new Traversable instance.

flatMap

public <U> PriorityQueue<U> flatMap(Comparator<U> comparator,
 Function<? super T, ? extends Iterable<? extends U>> mapper)

foldRight

public <U> U foldRight(U zero,
 BiFunction<? super T, ? super U, ? extends U> accumulator)

Accumulates the elements of this PriorityQueue by successively calling the given function f from the right, starting with a value zero of type B.

Example: PriorityQueue.of("a", "b", "c").foldRight("", (x, xs) -> x + xs) = "abc"

Specified by:

foldRight in interface Foldable<T>

Specified by:

foldRight in interface Traversable<T>

Type Parameters:

U - the type of the folded value

Parameters:

zero - Value to start the accumulation with.

accumulator - The accumulator function.

Returns:

an accumulated version of this.

Throws:

NullPointerException - if f is null

groupBy

public <C> Map<C, ? extends PriorityQueue<T>> groupBy(Function<? super T, ? extends C> classifier)

Description copied from interface: Traversable

Groups this elements by classifying the elements.

Specified by:

groupBy in interface Traversable<T>

Type Parameters:

C - classified class type

Parameters:

classifier - A function which classifies elements into classes

Returns:

A Map containing the grouped elements

See Also:

• Traversable.arrangeBy(Function)

grouped

public Iterator<? extends PriorityQueue<T>> grouped(int size)

Description copied from interface: Traversable

Groups this Traversable into fixed size blocks.

Let length be the length of this Iterable. Then grouped is defined as follows:

• If this.isEmpty(), the resulting Iterator is empty.
• If size <= length, the resulting Iterator will contain length / size blocks of size size and maybe a non-empty block of size length % size, if there are remaining elements.
• If size > length, the resulting Iterator will contain one block of size length.

Examples:

[].grouped(1) = []
[].grouped(0) throws
[].grouped(-1) throws
[1,2,3,4].grouped(2) = [[1,2],[3,4]]
[1,2,3,4,5].grouped(2) = [[1,2],[3,4],[5]]
[1,2,3,4].grouped(5) = [[1,2,3,4]]

Please note that grouped(int) is a special case of Traversable.sliding(int, int), i.e. grouped(size) is the same as sliding(size, size).

Specified by:

grouped in interface Traversable<T>

Parameters:

size - a positive block size

Returns:

A new Iterator of grouped blocks of the given size

hasDefiniteSize

public boolean hasDefiniteSize()

Checks if this PriorityQueue is known to have a finite size.

This method should be implemented by classes only, i.e. not by interfaces.

Specified by:

hasDefiniteSize in interface Traversable<T>

Returns:

true, if this PriorityQueue is known to have a finite size, false otherwise.

init

public PriorityQueue<T> init()

Dual of tail(), returning all elements except the last.

Specified by:

init in interface Traversable<T>

Specified by:

init in class AbstractQueue<T, PriorityQueue<T>>

Returns:

a new instance containing all elements except the last.

Throws:

UnsupportedOperationException - if this is empty

isTraversableAgain

public boolean isTraversableAgain()

Checks if this PriorityQueue can be repeatedly traversed.

This method should be implemented by classes only, i.e. not by interfaces.

Specified by:

isTraversableAgain in interface Traversable<T>

Returns:

true, if this PriorityQueue is known to be traversable repeatedly, false otherwise.

last

public T last()

Description copied from interface: Traversable

Dual of Traversable.head(), returning the last element.

Specified by:

last in interface Traversable<T>

Returns:

the last element.

length

public int length()

Computes the number of elements of this PriorityQueue.

Same as Traversable.size().

Specified by:

length in interface Traversable<T>

Returns:

the number of elements

map

public <U> PriorityQueue<U> map(Function<? super T, ? extends U> mapper)

Description copied from interface: Traversable

Maps the elements of this Traversable to elements of a new type preserving their order, if any.

Specified by:

map in interface Traversable<T>

Specified by:

map in interface Value<T>

Type Parameters:

U - Component type of the target Traversable

Parameters:

mapper - A mapper.

Returns:

a mapped Traversable

map

public <U> PriorityQueue<U> map(Comparator<U> comparator,
 Function<? super T, ? extends U> mapper)

orElse

public PriorityQueue<T> orElse(Iterable<? extends T> other)

Returns this PriorityQueue if it is nonempty, otherwise PriorityQueue created from iterable, using existing comparator.

Specified by:

orElse in interface Traversable<T>

Parameters:

other - An alternative Traversable

Returns:

this PriorityQueue if it is nonempty, otherwise PriorityQueue created from iterable, using existing comparator.

orElse

public PriorityQueue<T> orElse(Supplier<? extends Iterable<? extends T>> supplier)

Returns this PriorityQueue if it is nonempty, otherwise PriorityQueue created from result of evaluating supplier, using existing comparator.

Specified by:

orElse in interface Traversable<T>

Parameters:

supplier - An alternative Traversable

Returns:

this PriorityQueue if it is nonempty, otherwise PriorityQueue created from result of evaluating supplier, using existing comparator.

partition

public Tuple2<? extends PriorityQueue<T>, ? extends PriorityQueue<T>> partition(Predicate<? super T> predicate)

Description copied from interface: Traversable

Creates a partition of this Traversable by splitting this elements in two in distinct traversables according to a predicate.

Specified by:

partition in interface Traversable<T>

Parameters:

predicate - A predicate which classifies an element if it is in the first or the second traversable.

Returns:

A disjoint union of two traversables. The first Traversable contains all elements that satisfy the given predicate, the second Traversable contains all elements that don't. The original order of elements is preserved.

replace

public PriorityQueue<T> replace(T currentElement,
 T newElement)

Description copied from interface: Traversable

Replaces the first occurrence (if exists) of the given currentElement with newElement.

Specified by:

replace in interface Traversable<T>

Parameters:

currentElement - An element to be substituted.

newElement - A replacement for currentElement.

Returns:

a Traversable containing all elements of this where the first occurrence of currentElement is replaced with newElement.

replaceAll

public PriorityQueue<T> replaceAll(T currentElement,
 T newElement)

Description copied from interface: Traversable

Replaces all occurrences of the given currentElement with newElement.

Specified by:

replaceAll in interface Traversable<T>

Parameters:

currentElement - An element to be substituted.

newElement - A replacement for currentElement.

Returns:

a Traversable containing all elements of this where all occurrences of currentElement are replaced with newElement.

scan

public PriorityQueue<T> scan(T zero,
 BiFunction<? super T, ? super T, ? extends T> operation)

Description copied from interface: Traversable

Computes a prefix scan of the elements of the collection. Note: The neutral element z may be applied more than once.

Specified by:

scan in interface Traversable<T>

Parameters:

zero - neutral element for the operator op

operation - the associative operator for the scan

Returns:

a new traversable collection containing the prefix scan of the elements in this traversable collection

scanLeft

public <U> PriorityQueue<U> scanLeft(U zero,
 BiFunction<? super U, ? super T, ? extends U> operation)

Description copied from interface: Traversable

Produces a collection containing cumulative results of applying the operator going left to right. Note: will not terminate for infinite-sized collections. Note: might return different results for different runs, unless the underlying collection type is ordered.

Specified by:

scanLeft in interface Traversable<T>

Type Parameters:

U - the type of the elements in the resulting collection

Parameters:

zero - the initial value

operation - the binary operator applied to the intermediate result and the element

Returns:

collection with intermediate results

scanRight

public <U> PriorityQueue<U> scanRight(U zero,
 BiFunction<? super T, ? super U, ? extends U> operation)

Description copied from interface: Traversable

Produces a collection containing cumulative results of applying the operator going right to left. The head of the collection is the last cumulative result. Note: will not terminate for infinite-sized collections. Note: might return different results for different runs, unless the underlying collection type is ordered.

Specified by:

scanRight in interface Traversable<T>

Type Parameters:

U - the type of the elements in the resulting collection

Parameters:

zero - the initial value

operation - the binary operator applied to the intermediate result and the element

Returns:

collection with intermediate results

slideBy

public Iterator<? extends PriorityQueue<T>> slideBy(Function<? super T, ?> classifier)

Description copied from interface: Traversable

Slides a non-overlapping window of a variable size over this Traversable.

Each window contains elements with the same class, as determined by classifier. Two consecutive values in this Traversable will be in the same window only if classifier returns equal values for them. Otherwise, the values will constitute the last element of the previous window and the first element of the next window.

Examples:

[].slideBy(Function.identity()) = []
[1,2,3,4,4,5].slideBy(Function.identity()) = [[1],[2],[3],[4,4],[5]]
[1,2,3,10,12,5,7,20,29].slideBy(x -> x/10) = [[1,2,3],[10,12],[5,7],[20,29]]

Specified by:

slideBy in interface Traversable<T>

Parameters:

classifier - A function which classifies elements into classes

Returns:

A new Iterator of windows of the grouped elements

sliding

public Iterator<? extends PriorityQueue<T>> sliding(int size)

Description copied from interface: Traversable

Slides a window of a specific size and step size 1 over this Traversable by calling Traversable.sliding(int, int).

Specified by:

sliding in interface Traversable<T>

Parameters:

size - a positive window size

Returns:

a new Iterator of windows of a specific size using step size 1

sliding

public Iterator<? extends PriorityQueue<T>> sliding(int size,
 int step)

Description copied from interface: Traversable

Slides a window of a specific size and step size over this Traversable.

Examples:

[].sliding(1,1) = []
[1,2,3,4,5].sliding(2,3) = [[1,2],[4,5]]
[1,2,3,4,5].sliding(2,4) = [[1,2],[5]]
[1,2,3,4,5].sliding(2,5) = [[1,2]]
[1,2,3,4].sliding(5,3) = [[1,2,3,4],[4]]

Specified by:

sliding in interface Traversable<T>

Parameters:

size - a positive window size

step - a positive step size

Returns:

a new Iterator of windows of a specific size using a specific step size

span

public Tuple2<? extends PriorityQueue<T>, ? extends PriorityQueue<T>> span(Predicate<? super T> predicate)

Description copied from interface: Traversable

Returns a tuple where the first element is the longest prefix of elements that satisfy the given predicate and the second element is the remainder.

Specified by:

span in interface Traversable<T>

Parameters:

predicate - A predicate.

Returns:

a Tuple containing the longest prefix of elements that satisfy p and the remainder.

take

public PriorityQueue<T> take(int n)

Description copied from interface: Traversable

Takes the first n elements of this or all elements, if this length < n.

The result is equivalent to sublist(0, max(0, min(length(), n))) but does not throw if n < 0 or n > length().

In the case of n < 0 the empty instance is returned, in the case of n > length() this is returned.

Specified by:

take in interface Traversable<T>

Parameters:

n - The number of elements to take.

Returns:

A new instance consisting of the first n elements of this or all elements, if this has less than n elements.

takeRight

public PriorityQueue<T> takeRight(int n)

Description copied from interface: Traversable

Takes the last n elements of this or all elements, if this length < n.

The result is equivalent to sublist(max(0, min(length(), length() - n)), n), i.e. takeRight will not throw if n < 0 or n > length().

In the case of n < 0 the empty instance is returned, in the case of n > length() this is returned.

Specified by:

takeRight in interface Traversable<T>

Parameters:

n - The number of elements to take.

Returns:

A new instance consisting of the last n elements of this or all elements, if this has less than n elements.

takeUntil

public PriorityQueue<T> takeUntil(Predicate<? super T> predicate)

Description copied from interface: Traversable

Takes elements until the predicate holds for the current element.

Note: This is essentially the same as takeWhile(predicate.negate()). It is intended to be used with method references, which cannot be negated directly.

Specified by:

takeUntil in interface Traversable<T>

Specified by:

takeUntil in class AbstractQueue<T, PriorityQueue<T>>

Parameters:

predicate - A condition tested subsequently for this elements.

Returns:

a new instance consisting of all elements before the first one which does satisfy the given predicate.

unzip

public <T1,T2>
Tuple2<? extends PriorityQueue<T1>, ? extends PriorityQueue<T2>> unzip(Function<? super T, Tuple2<? extends T1, ? extends T2>> unzipper)

Description copied from interface: Traversable

Unzips this elements by mapping this elements to pairs which are subsequently split into two distinct sets.

Specified by:

unzip in interface Traversable<T>

Type Parameters:

T1 - 1st element type of a pair returned by unzipper

T2 - 2nd element type of a pair returned by unzipper

Parameters:

unzipper - a function which converts elements of this to pairs

Returns:

A pair of set containing elements split by unzipper

unzip3

public <T1,T2,T3>
Tuple3<? extends PriorityQueue<T1>, ? extends PriorityQueue<T2>, ? extends PriorityQueue<T3>> unzip3(Function<? super T, Tuple3<? extends T1, ? extends T2, ? extends T3>> unzipper)

Description copied from interface: Traversable

Unzips this elements by mapping this elements to triples which are subsequently split into three distinct sets.

Specified by:

unzip3 in interface Traversable<T>

Type Parameters:

T1 - 1st element type of a triplet returned by unzipper

T2 - 2nd element type of a triplet returned by unzipper

T3 - 3rd element type of a triplet returned by unzipper

Parameters:

unzipper - a function which converts elements of this to pairs

Returns:

A triplet of set containing elements split by unzipper

zip

public <U> PriorityQueue<Tuple2<T,U>> zip(Iterable<? extends U> that)

Description copied from interface: Traversable

Returns a traversable formed from this traversable and another Iterable collection by combining corresponding elements in pairs. If one of the two iterables is longer than the other, its remaining elements are ignored.

The length of the returned traversable is the minimum of the lengths of this traversable and that iterable.

Specified by:

zip in interface Traversable<T>

Type Parameters:

U - The type of the second half of the returned pairs.

Parameters:

that - The Iterable providing the second half of each result pair.

Returns:

a new traversable containing pairs consisting of corresponding elements of this traversable and that iterable.

zipWith

public <U,R> PriorityQueue<R> zipWith(Iterable<? extends U> that,
 BiFunction<? super T, ? super U, ? extends R> mapper)

Description copied from interface: Traversable

Returns a traversable formed from this traversable and another Iterable collection by mapping elements. If one of the two iterables is longer than the other, its remaining elements are ignored.

The length of the returned traversable is the minimum of the lengths of this traversable and that iterable.

Specified by:

zipWith in interface Traversable<T>

Type Parameters:

U - The type of the second parameter of the mapper.

R - The type of the mapped elements.

Parameters:

that - The Iterable providing the second parameter of the mapper.

mapper - a mapper.

Returns:

a new traversable containing mapped elements of this traversable and that iterable.

zipAll

public <U> PriorityQueue<Tuple2<T,U>> zipAll(Iterable<? extends U> that,
 T thisElem,
 U thatElem)

Description copied from interface: Traversable

Returns a traversable formed from this traversable and another Iterable by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.

The length of the returned traversable is the maximum of the lengths of this traversable and that iterable.

Special case: if this traversable is shorter than that elements, and that elements contains duplicates, the resulting traversable may be shorter than the maximum of the lengths of this and that because a traversable contains an element at most once.

If this Traversable is shorter than that, thisElem values are used to fill the result. If that is shorter than this Traversable, thatElem values are used to fill the result.

Specified by:

zipAll in interface Traversable<T>

Type Parameters:

U - The type of the second half of the returned pairs.

Parameters:

that - The Iterable providing the second half of each result pair.

thisElem - The element to be used to fill up the result if this traversable is shorter than that.

thatElem - The element to be used to fill up the result if that is shorter than this traversable.

Returns:

A new traversable containing pairs consisting of corresponding elements of this traversable and that.

zipWithIndex

public PriorityQueue<Tuple2<T,Integer>> zipWithIndex()

Description copied from interface: Traversable

Zips this traversable with its indices.

Specified by:

zipWithIndex in interface Traversable<T>

Returns:

A new traversable containing all elements of this traversable paired with their index, starting with 0.

zipWithIndex

public <U> PriorityQueue<U> zipWithIndex(BiFunction<? super T, ? super Integer, ? extends U> mapper)

Description copied from interface: Traversable

Zips this traversable with its indices by applying mapper provided.

Specified by:

zipWithIndex in interface Traversable<T>

Type Parameters:

U - The type of the mapped elements.

Parameters:

mapper - a mapper.

Returns:

a new traversable containing elements of this traversable, zipped with indices, and mapped with mapper provided.

stringPrefix

public String stringPrefix()

Description copied from interface: Value

Returns the name of this Value type, which is used by toString().

Specified by:

stringPrefix in interface Value<T>

Returns:

This type name.

equals

public boolean equals(Object o)

Description copied from interface: Traversable

In Vavr there are four basic classes of collections:

• Seq (sequential elements)
• Set (distinct elements)
• Map (indexed elements)
• Multimap (indexed collections)

Two collection instances of these classes are equal if and only if both collections

• belong to the same basic collection class (Seq, Set, Map or Multimap)
• contain the same elements
• have the same element order, if the collections are of type Seq

Two Map/Multimap elements, resp. entries, (key1, value1) and (key2, value2) are equal, if the keys are equal and the values are equal.

Notes:

• No collection instance equals null, e.g. Queue(1) not equals null.
• Nulls are allowed and handled as expected, e.g. List(null, 1) equals Stream(null, 1) and HashMap((null, 1)) equals LinkedHashMap((null, 1)).
• The element order is taken into account for Seq only. E.g. List(null, 1) not equals Stream(1, null) and HashMap((null, 1), ("a", null)) equals LinkedHashMap(("a", null), (null, 1)). The reason is, that we do not know which implementations we compare when having two instances of type Map, Multimap or Set (see Liskov Substitution Principle).
• Other collection classes are equal if their types are equal and their elements are equal (in iteration order).
• Iterator equality is defined to be object reference equality.

Specified by:

equals in interface Traversable<T>

Specified by:

equals in interface Value<T>

Overrides:

equals in class Object

Parameters:

o - an object, may be null

Returns:

true, if this collection equals the given object according to the rules described above, false otherwise.

hashCode

public int hashCode()

Description copied from interface: Traversable

Returns the hash code of this collection.
We distinguish between two types of hashes, those for collections with predictable iteration order (like Seq) and those with arbitrary iteration order (like Set, Map and Multimap).
In all cases the hash of an empty collection is defined to be 1.
Collections with predictable iteration order are hashed as follows:

int hash = 1;
for (T t : this) { hash = hash * 31 + Objects.hashCode(t); }

Collections with arbitrary iteration order are hashed in a way such that the hash of a fixed number of elements is independent of their iteration order.

int hash = 1;
for (T t : this) { hash += Objects.hashCode(t); }

Please note that the particular hashing algorithms may change in a future version of Vavr.
Generally, hash codes of collections aren't cached in Vavr (opposed to the size/length). Storing hash codes in order to reduce the time complexity would increase the memory footprint. Persistent collections are built upon tree structures, it allows us to implement efficient memory sharing. A drawback of tree structures is that they make it necessary to store collection attributes at each tree node (read: element).
The computation of the hash code is linear in time, i.e. O(n). If the hash code of a collection is re-calculated often, e.g. when using a List as HashMap key, we might want to cache the hash code. This can be achieved by simply using a wrapper class, which is not included in Vavr but could be implemented like this:

public final class Hashed<K> {

    private final K key;
    private final Lazy<Integer> hashCode;

    public Hashed(K key) {
        this.key = key;
        this.hashCode = Lazy.of(() -> Objects.hashCode(key));
    }

    public K key() {
        return key;
    }

    &#64;Override
    public boolean equals(Object o) {
        if (o == key) {
            return true;
        } else if (key != null && o instanceof Hashed) {
            final Hashed that = (Hashed) o;
            return key.equals(that.key);
        } else {
            return false;
        }
    }

    &#64;Override
    public int hashCode() {
        return hashCode.get();
    }

    &#64;Override
    public String toString() {
        return "Hashed(" + (key == null ? "null" : key.toString()) + ")";
    }
}

Specified by:

hashCode in interface Traversable<T>

Specified by:

hashCode in interface Value<T>

Overrides:

hashCode in class Object

Returns:

The hash code of this collection

comparator

public Comparator<T> comparator()

Description copied from interface: Ordered

Returns the comparator which defines the order of the elements contained in this collection.

Specified by:

comparator in interface Ordered<T>

Returns:

The comparator that defines the order of this collection's elements.