Class Queue<T>
- Type Parameters:
T
- Component type of the Queue
- All Implemented Interfaces:
Foldable<T>
,LinearSeq<T>
,Seq<T>
,Traversable<T>
,Function1<Integer,
,T> PartialFunction<Integer,
,T> Value<T>
,Serializable
,Iterable<T>
,Function<Integer,
T>
Queue
stores elements allowing a first-in-first-out (FIFO) retrieval.
Queue API:
AbstractQueue.dequeue()
AbstractQueue.dequeueOption()
enqueue(Object)
AbstractQueue.enqueue(Object[])
enqueueAll(Iterable)
AbstractQueue.peek()
AbstractQueue.peekOption()
When the front list is empty, front and rear are swapped and rear is reversed. This implies the following queue
invariant: front.isEmpty() => rear.isEmpty()
.
See Okasaki, Chris: Purely Functional Data Structures (p. 42 ff.). Cambridge, 2003.
- See Also:
-
Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionAppends an element to this.Appends all given elements to this.asJava()
Creates an immutableList
view on top of thisSeq
, i.e.Creates a mutableList
view on top of thisSeq
, i.e.asJavaMutable
(Consumer<? super List<T>> action) <R> Queue
<R> collect
(PartialFunction<? super T, ? extends R> partialFunction) Collects all elements that are in the domain of the givenpartialFunction
by mapping the elements to typeR
.Returns aCollector
which may be used in conjunction withStream.collect(java.util.stream.Collector)
to obtain aQueue
.Returns the union of all combinations from k = 0 to length().combinations
(int k) Returns the k-combination of this traversable, i.e.crossProduct
(int power) Calculates the n-ary cartesian power (or cross product or simply product) of this.distinct()
Returns a new version of this which contains no duplicates.distinctBy
(Comparator<? super T> comparator) Returns a new version of this which contains no duplicates.distinctBy
(Function<? super T, ? extends U> keyExtractor) Returns a new version of this which contains no duplicates.drop
(int n) Drops the first n elements of this or all elements, if this length < n.dropRight
(int n) Drops the last n elements of this or all elements, if this length < n.dropRightUntil
(Predicate<? super T> predicate) Drops elements until the predicate holds for the current element, starting from the end.dropRightWhile
(Predicate<? super T> predicate) Drops elements while the predicate holds for the current element, starting from the end.Drops elements while the predicate holds for the current element.static <T> Queue
<T> empty()
Returns the empty Queue.Enqueues a new element.enqueueAll
(Iterable<? extends T> elements) Enqueues the given elements.boolean
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> Queue
<T> Returns a Queue containingn
values supplied by a given Suppliers
.static <T> Queue
<T> fill
(int n, T element) Returns a Queue containingn
times the givenelement
Returns a new traversable consisting of all elements which satisfy the given predicate.<U> Queue
<U> FlatMaps this Traversable.get
(int index) Returns the element at the specified index.Groups this elements by classifying the elements.grouped
(int size) Groups thisTraversable
into fixed size blocks.boolean
Checks if this Traversable is known to have a finite size.int
hashCode()
Returns the hash code of this collection.head()
Returns the first element of a non-empty Traversable.int
Returns the index of the first occurrence of the given element after or at some start index or -1 if this does not contain the given element.init()
Dual of AbstractQueue.tail(), returning all elements except the last.Inserts the given element at the specified index.Inserts the given elements at the specified index.intersperse
(T element) Inserts an element between all elements of this Traversable.boolean
isAsync()
AQueue
is computed synchronously.boolean
isEmpty()
Checks if this Traversable is empty.boolean
isLazy()
AQueue
is computed eagerly.boolean
Checks if this Traversable can be repeatedly traversed.last()
Dual of Traversable.head(), returning the last element.int
lastIndexOf
(T element, int end) Returns the index of the last occurrence of the given element before or at a given end index or -1 if this does not contain the given element.A copy of this sequence with an element prepended until a given target length is reached.int
length()
Computes the number of elements of this Traversable.<U> Queue
<U> Maps the elements of thisTraversable
to elements of a new type preserving their order, if any.static <T> Queue
<T> Narrows a widenedQueue<? extends T>
toQueue<T>
by performing a type-safe cast.static <T> Queue
<T> of
(T element) Returns a singletonQueue
, i.e.static <T> Queue
<T> of
(T... elements) Creates a Queue of the given elements.ofAll
(boolean... elements) Creates a Queue from boolean values.ofAll
(byte... elements) Creates a Queue from byte values.ofAll
(char... elements) Creates a Queue from char values.ofAll
(double... elements) Creates a Queue from double values.ofAll
(float... elements) Creates a Queue from float values.ofAll
(int... elements) Creates a Queue from int values.ofAll
(long... elements) Creates a Queue from long values.ofAll
(short... elements) Creates a Queue from short values.static <T> Queue
<T> Creates a Queue of the given elements.static <T> Queue
<T> Creates a Queue that contains the elements of the givenStream
.Returns thisTraversable
if it is nonempty, otherwise return the alternative.Returns thisTraversable
if it is nonempty, otherwise return the result of evaluating supplier.A copy of this sequence with an element appended until a given target length is reached.Creates a partition of thisTraversable
by splitting this elements in two in distinct traversables according to a predicate.Produces a new list where a slice of elements in this list is replaced by another sequence.Computes all unique permutations.Prepends an element to this.prependAll
(Iterable<? extends T> elements) Prepends all given elements to this.range
(char from, char toExclusive) range
(int from, int toExclusive) Creates a Queue of int numbers starting fromfrom
, extending totoExclusive - 1
.range
(long from, long toExclusive) Creates a Queue of long numbers starting fromfrom
, extending totoExclusive - 1
.rangeBy
(char from, char toExclusive, int step) rangeBy
(double from, double toExclusive, double step) rangeBy
(int from, int toExclusive, int step) Creates a Queue of int numbers starting fromfrom
, extending totoExclusive - 1
, withstep
.rangeBy
(long from, long toExclusive, long step) Creates a Queue of long numbers starting fromfrom
, extending totoExclusive - 1
, withstep
.rangeClosed
(char from, char toInclusive) rangeClosed
(int from, int toInclusive) Creates a Queue of int numbers starting fromfrom
, extending totoInclusive
.rangeClosed
(long from, long toInclusive) Creates a Queue of long numbers starting fromfrom
, extending totoInclusive
.rangeClosedBy
(char from, char toInclusive, int step) rangeClosedBy
(double from, double toInclusive, double step) rangeClosedBy
(int from, int toInclusive, int step) Creates a Queue of int numbers starting fromfrom
, extending totoInclusive
, withstep
.rangeClosedBy
(long from, long toInclusive, long step) Creates a Queue of long numbers starting fromfrom
, extending totoInclusive
, withstep
.private Object
Removes the first occurrence of the given element.Removes all occurrences of the given element.removeAt
(int index) Removes the element at the specified position in this sequence.removeFirst
(Predicate<T> predicate) Removes the first occurrence that satisfy predicateremoveLast
(Predicate<T> predicate) Removes the last occurrence that satisfy predicateReplaces the first occurrence (if exists) of the given currentElement with newElement.replaceAll
(T currentElement, T newElement) Replaces all occurrences of the given currentElement with newElement.reverse()
Reverses the order of elements.rotateLeft
(int n) Circular rotates the elements by the specified distance to the left direction.rotateRight
(int n) Circular rotates the elements by the specified distance to the right direction.Computes a prefix scan of the elements of the collection.<U> Queue
<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> Queue
<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.shuffle()
Randomize the order of the elements in the current sequence.slice
(int beginIndex, int endIndex) Returns a Seq that is a slice of this.Slides a non-overlapping window of a variable size over thisTraversable
.sliding
(int size) Slides a window of a specificsize
and step size 1 over thisTraversable
by callingTraversable.sliding(int, int)
.sliding
(int size, int step) Slides a window of a specificsize
andstep
size over thisTraversable
.sortBy
(Comparator<? super U> comparator, Function<? super T, ? extends U> mapper) Sorts this elements by comparing the elements in a different domain, using the givenmapper
.<U extends Comparable<? super U>>
Queue<T> Sorts this elements by comparing the elements in a different domain, using the givenmapper
.sorted()
Sorts this elements according to their natural order.sorted
(Comparator<? super T> comparator) Sorts this elements according to the providedComparator
.Returns a tuple where the first element is the longest prefix of elements that satisfy the givenpredicate
and the second element is the remainder.splitAt
(int n) Splits a Seq at the specified index.Splits a sequence at the first element which satisfies thePredicate
, e.g.splitAtInclusive
(Predicate<? super T> predicate) Splits a sequence at the first element which satisfies thePredicate
, e.g.boolean
startsWith
(Iterable<? extends T> that, int offset) Tests whether this list contains the given sequence at a given index.Returns the name of this Value type, which is used by toString().subSequence
(int beginIndex) Returns a Seq that is a subsequence of this.subSequence
(int beginIndex, int endIndex) Returns a Seq that is a subsequence of this.static <T> Queue
<T> Returns a Queue containingn
values of a given Functionf
over a range of integer values from 0 ton - 1
.tail()
Drops the first element of a non-empty Traversable.take
(int n) Takes the first n elements of this or all elements, if this length < n.takeRight
(int n) Takes the last n elements of this or all elements, if this length < n.takeRightUntil
(Predicate<? super T> predicate) Takes elements until the predicate holds for the current element, starting from the end.takeRightWhile
(Predicate<? super T> predicate) Takes elements while the predicate holds for the current element, starting from the end.Takes elements until the predicate holds for the current element.<U> U
Transforms thisQueue
.Transposes the rows and columns of aQueue
matrix.static <T> Queue
<T> Creates a Queue from a seed value and a function.static <T,
U> Queue <U> unfoldLeft
(T seed, Function<? super T, Option<Tuple2<? extends T, ? extends U>>> f) Creates a Queue from a seed value and a function.static <T,
U> Queue <U> unfoldRight
(T seed, Function<? super T, Option<Tuple2<? extends U, ? extends T>>> f) Creates a Queue from a seed value and a function.Unzips this elements by mapping this elements to pairs which are subsequently split into two distinct sets.Unzips this elements by mapping this elements to triples which are subsequently split into three distinct sets.Updates the given element at the specified index using the specified function.Updates the given element at the specified index.Returns a traversable formed from this traversable and another Iterable collection by combining corresponding elements in pairs.Returns a traversable formed from this traversable and another Iterable by combining corresponding elements in pairs.<U,
R> Queue <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.Zips this traversable with its indices.<U> Queue
<U> zipWithIndex
(BiFunction<? super T, ? super Integer, ? extends U> mapper) Zips this traversable with its indices by applying mapper provided.Methods inherited from class io.vavr.collection.AbstractQueue
dequeue, dequeueOption, dropUntil, enqueue, initOption, peek, peek, peekOption, reject, removeAll, removeAll, retainAll, tailOption, takeWhile, toString
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface io.vavr.collection.Foldable
fold, reduce, reduceOption
Methods inherited from interface io.vavr.Function1
andThen, arity, compose, curried, isMemoized, memoized, partial, reversed, tupled
Methods inherited from interface io.vavr.collection.LinearSeq
asPartialFunction, dropUntil, indexOfSlice, indexWhere, initOption, isDefinedAt, lastIndexOfSlice, lastIndexWhere, peek, reject, removeAll, removeAll, retainAll, reverseIterator, search, search, segmentLength, tailOption, takeWhile
Methods inherited from interface io.vavr.collection.Seq
apply, containsSlice, crossProduct, crossProduct, endsWith, foldRight, indexOf, indexOfOption, indexOfOption, indexOfSlice, indexOfSliceOption, indexOfSliceOption, indexWhere, indexWhereOption, indexWhereOption, isSequential, iterator, lastIndexOf, lastIndexOfOption, lastIndexOfOption, lastIndexOfSlice, lastIndexOfSliceOption, lastIndexOfSliceOption, lastIndexWhere, lastIndexWhereOption, lastIndexWhereOption, lift, prefixLength, startsWith, withDefault, withDefaultValue
Methods inherited from interface io.vavr.collection.Traversable
arrangeBy, average, containsAll, count, existsUnique, find, findLast, foldLeft, forEachWithIndex, get, headOption, isDistinct, isOrdered, 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 io.vavr.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, toList, toMap, toMap, toOption, toPriorityQueue, toPriorityQueue, toQueue, toRight, toRight, toSet, toSortedMap, toSortedMap, toSortedMap, toSortedMap, toSortedSet, toSortedSet, toStream, toString, toTree, toTree, toTry, toTry, toValid, toValid, toValidation, toValidation, toVector
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Field Details
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serialVersionUID
private static final long serialVersionUID- See Also:
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EMPTY
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front
-
rear
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Constructor Details
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Queue
Creates a Queue consisting of a front List and a rear List.For a
Queue(front, rear)
the following invariant holds:Queue is empty <=> front is empty
. In other words: If the Queue is not empty, the front List contains at least one element.- Parameters:
front
- A List of front elements, in correct order.rear
- A List of rear elements, in reverse order.
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Method Details
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collector
Returns aCollector
which may be used in conjunction withStream.collect(java.util.stream.Collector)
to obtain aQueue
.- Type Parameters:
T
- Component type of the Queue.- Returns:
- A io.vavr.collection.Queue Collector.
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empty
Returns the empty Queue.- Type Parameters:
T
- Component type- Returns:
- The empty Queue.
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narrow
Narrows a widenedQueue<? extends T>
toQueue<T>
by performing a type-safe cast. This is eligible because immutable/read-only collections are covariant.- Type Parameters:
T
- Component type of theQueue
.- Parameters:
queue
- AnQueue
.- Returns:
- the given
queue
instance as narrowed typeQueue<T>
.
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of
Returns a singletonQueue
, i.e. aQueue
of one element.- Type Parameters:
T
- The component type- Parameters:
element
- An element.- Returns:
- A new Queue instance containing the given element
-
of
Creates a Queue of the given elements.- Type Parameters:
T
- Component type of the Queue.- Parameters:
elements
- Zero or more elements.- Returns:
- A queue containing the given elements in the same order.
- Throws:
NullPointerException
- ifelements
is null
-
ofAll
Creates a Queue of the given elements.- Type Parameters:
T
- Component type of the Queue.- Parameters:
elements
- An Iterable of elements.- Returns:
- A queue containing the given elements in the same order.
- Throws:
NullPointerException
- ifelements
is null
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ofAll
Creates a Queue that contains the elements of the givenStream
.- Type Parameters:
T
- Component type of the Stream.- Parameters:
javaStream
- AStream
- Returns:
- A Queue containing the given elements in the same order.
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ofAll
Creates a Queue from boolean values.- Parameters:
elements
- boolean values- Returns:
- A new Queue of Boolean values
- Throws:
NullPointerException
- if elements is null
-
ofAll
Creates a Queue from byte values.- Parameters:
elements
- byte values- Returns:
- A new Queue of Byte values
- Throws:
NullPointerException
- if elements is null
-
ofAll
Creates a Queue from char values.- Parameters:
elements
- char values- Returns:
- A new Queue of Character values
- Throws:
NullPointerException
- if elements is null
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ofAll
Creates a Queue from double values.- Parameters:
elements
- double values- Returns:
- A new Queue of Double values
- Throws:
NullPointerException
- if elements is null
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ofAll
Creates a Queue from float values.- Parameters:
elements
- float values- Returns:
- A new Queue of Float values
- Throws:
NullPointerException
- if elements is null
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ofAll
Creates a Queue from int values.- Parameters:
elements
- int values- Returns:
- A new Queue of Integer values
- Throws:
NullPointerException
- if elements is null
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ofAll
Creates a Queue from long values.- Parameters:
elements
- long values- Returns:
- A new Queue of Long values
- Throws:
NullPointerException
- if elements is null
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ofAll
Creates a Queue from short values.- Parameters:
elements
- short values- Returns:
- A new Queue of Short values
- Throws:
NullPointerException
- if elements is null
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tabulate
Returns a Queue containingn
values of a given Functionf
over a range of integer values from 0 ton - 1
.- Type Parameters:
T
- Component type of the Queue- Parameters:
n
- The number of elements in the Queuef
- The Function computing element values- Returns:
- A Queue consisting of elements
f(0),f(1), ..., f(n - 1)
- Throws:
NullPointerException
- iff
is null
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fill
Returns a Queue containingn
values supplied by a given Suppliers
.- Type Parameters:
T
- Component type of the Queue- Parameters:
n
- The number of elements in the Queues
- The Supplier computing element values- Returns:
- An Queue of size
n
, where each element contains the result supplied bys
. - Throws:
NullPointerException
- ifs
is null
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fill
Returns a Queue containingn
times the givenelement
- Type Parameters:
T
- Component type of the Queue- Parameters:
n
- The number of elements in the Queueelement
- The element- Returns:
- An Queue of size
n
, where each element is the givenelement
.
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range
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rangeBy
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rangeBy
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range
Creates a Queue of int numbers starting fromfrom
, extending totoExclusive - 1
.Examples:
Queue.range(0, 0) // = Queue() Queue.range(2, 0) // = Queue() Queue.range(-2, 2) // = Queue(-2, -1, 0, 1)
- Parameters:
from
- the first numbertoExclusive
- the last number + 1- Returns:
- a range of int values as specified or
Nil
iffrom >= toExclusive
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rangeBy
Creates a Queue of int numbers starting fromfrom
, extending totoExclusive - 1
, withstep
.Examples:
Queue.rangeBy(1, 3, 1) // = Queue(1, 2) Queue.rangeBy(1, 4, 2) // = Queue(1, 3) Queue.rangeBy(4, 1, -2) // = Queue(4, 2) Queue.rangeBy(4, 1, 2) // = Queue()
- Parameters:
from
- the first numbertoExclusive
- the last number + 1step
- the step- Returns:
- a range of long values as specified or
Nil
if
from >= toInclusive
andstep > 0
or
from <= toInclusive
andstep < 0
- Throws:
IllegalArgumentException
- ifstep
is zero
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range
Creates a Queue of long numbers starting fromfrom
, extending totoExclusive - 1
.Examples:
Queue.range(0L, 0L) // = Queue() Queue.range(2L, 0L) // = Queue() Queue.range(-2L, 2L) // = Queue(-2L, -1L, 0L, 1L)
- Parameters:
from
- the first numbertoExclusive
- the last number + 1- Returns:
- a range of long values as specified or
Nil
iffrom >= toExclusive
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rangeBy
Creates a Queue of long numbers starting fromfrom
, extending totoExclusive - 1
, withstep
.Examples:
Queue.rangeBy(1L, 3L, 1L) // = Queue(1L, 2L) Queue.rangeBy(1L, 4L, 2L) // = Queue(1L, 3L) Queue.rangeBy(4L, 1L, -2L) // = Queue(4L, 2L) Queue.rangeBy(4L, 1L, 2L) // = Queue()
- Parameters:
from
- the first numbertoExclusive
- the last number + 1step
- the step- Returns:
- a range of long values as specified or
Nil
if
from >= toInclusive
andstep > 0
or
from <= toInclusive
andstep < 0
- Throws:
IllegalArgumentException
- ifstep
is zero
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rangeClosed
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rangeClosedBy
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rangeClosedBy
@GwtIncompatible public static Queue<Double> rangeClosedBy(double from, double toInclusive, double step) -
rangeClosed
Creates a Queue of int numbers starting fromfrom
, extending totoInclusive
.Examples:
Queue.rangeClosed(0, 0) // = Queue(0) Queue.rangeClosed(2, 0) // = Queue() Queue.rangeClosed(-2, 2) // = Queue(-2, -1, 0, 1, 2)
- Parameters:
from
- the first numbertoInclusive
- the last number- Returns:
- a range of int values as specified or
Nil
iffrom > toInclusive
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rangeClosedBy
Creates a Queue of int numbers starting fromfrom
, extending totoInclusive
, withstep
.Examples:
Queue.rangeClosedBy(1, 3, 1) // = Queue(1, 2, 3) Queue.rangeClosedBy(1, 4, 2) // = Queue(1, 3) Queue.rangeClosedBy(4, 1, -2) // = Queue(4, 2) Queue.rangeClosedBy(4, 1, 2) // = Queue()
- Parameters:
from
- the first numbertoInclusive
- the last numberstep
- the step- Returns:
- a range of int values as specified or
Nil
if
from > toInclusive
andstep > 0
or
from < toInclusive
andstep < 0
- Throws:
IllegalArgumentException
- ifstep
is zero
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rangeClosed
Creates a Queue of long numbers starting fromfrom
, extending totoInclusive
.Examples:
Queue.rangeClosed(0L, 0L) // = Queue(0L) Queue.rangeClosed(2L, 0L) // = Queue() Queue.rangeClosed(-2L, 2L) // = Queue(-2L, -1L, 0L, 1L, 2L)
- Parameters:
from
- the first numbertoInclusive
- the last number- Returns:
- a range of long values as specified or
Nil
iffrom > toInclusive
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transpose
Transposes the rows and columns of aQueue
matrix.- Type Parameters:
T
- matrix element type- Parameters:
matrix
- to be transposed.- Returns:
- a transposed
Queue
matrix. - Throws:
IllegalArgumentException
- if the row lengths ofmatrix
differ.ex:
Queue.transpose(Queue(Queue(1,2,3), Queue(4,5,6))) → Queue(Queue(1,4), Queue(2,5), Queue(3,6))
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rangeClosedBy
Creates a Queue of long numbers starting fromfrom
, extending totoInclusive
, withstep
.Examples:
Queue.rangeClosedBy(1L, 3L, 1L) // = Queue(1L, 2L, 3L) Queue.rangeClosedBy(1L, 4L, 2L) // = Queue(1L, 3L) Queue.rangeClosedBy(4L, 1L, -2L) // = Queue(4L, 2L) Queue.rangeClosedBy(4L, 1L, 2L) // = Queue()
- Parameters:
from
- the first numbertoInclusive
- the last numberstep
- the step- Returns:
- a range of int values as specified or
Nil
if
from > toInclusive
andstep > 0
or
from < toInclusive
andstep < 0
- Throws:
IllegalArgumentException
- ifstep
is zero
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unfoldRight
public static <T,U> Queue<U> unfoldRight(T seed, Function<? super T, Option<Tuple2<? extends U, ? extends T>>> f) Creates a Queue from a seed value and a function. The function takes the seed at first. The function should returnNone
when it's done generating the Queue, otherwiseSome
Tuple
of the element for the next call and the value to add to the resulting Queue.Example:
Queue.unfoldRight(10, x -> x == 0 ? Option.none() : Option.of(new Tuple2<>(x, x-1))); // Queue(10, 9, 8, 7, 6, 5, 4, 3, 2, 1))
- Type Parameters:
T
- type of seedsU
- type of unfolded values- Parameters:
seed
- the start value for the iterationf
- the function to get the next step of the iteration- Returns:
- a Queue with the values built up by the iteration
- Throws:
NullPointerException
- iff
is null
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unfoldLeft
public static <T,U> Queue<U> unfoldLeft(T seed, Function<? super T, Option<Tuple2<? extends T, ? extends U>>> f) Creates a Queue from a seed value and a function. The function takes the seed at first. The function should returnNone
when it's done generating the Queue, otherwiseSome
Tuple
of the value to add to the resulting Queue and the element for the next call.Example:
Queue.unfoldLeft(10, x -> x == 0 ? Option.none() : Option.of(new Tuple2<>(x-1, x))); // Queue(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))
- Type Parameters:
T
- type of seedsU
- type of unfolded values- Parameters:
seed
- the start value for the iterationf
- the function to get the next step of the iteration- Returns:
- a Queue with the values built up by the iteration
- Throws:
NullPointerException
- iff
is null
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unfold
public static <T> Queue<T> unfold(T seed, Function<? super T, Option<Tuple2<? extends T, ? extends T>>> f) Creates a Queue from a seed value and a function. The function takes the seed at first. The function should returnNone
when it's done generating the Queue, otherwiseSome
Tuple
of the value to add to the resulting Queue and the element for the next call.Example:
Queue.unfold(10, x -> x == 0 ? Option.none() : Option.of(new Tuple2<>(x-1, x))); // Queue(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))
- Type Parameters:
T
- type of seeds and unfolded values- Parameters:
seed
- the start value for the iterationf
- the function to get the next step of the iteration- Returns:
- a Queue with the values built up by the iteration
- Throws:
NullPointerException
- iff
is null
-
enqueue
Enqueues a new element.- Specified by:
enqueue
in classAbstractQueue<T,
Queue<T>> - Parameters:
element
- The new element- Returns:
- a new
Queue
instance, containing the new element
-
enqueueAll
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 classAbstractQueue<T,
Queue<T>> - Parameters:
elements
- An Iterable of elements, may be empty- Returns:
- a new
Queue
instance, containing the new elements - Throws:
NullPointerException
- if elements is null
-
append
Description copied from interface:Seq
Appends an element to this. -
appendAll
Description copied from interface:Seq
Appends all given elements to this. -
asJava
Description copied from interface:Seq
Creates an immutableList
view on top of thisSeq
, i.e. calling mutators will result inUnsupportedOperationException
at runtime.The difference to conversion methods
toJava*()
is that- A view is created in O(1) (constant time) whereas conversion takes O(n) (linear time), with n = collection size.
- The operations on a view have the same performance characteristics than the underlying persistent Vavr collection whereas the performance characteristics of a converted collection are those of the Java standard collections.
java.util.List
view throwsUnsupportedOperationException
before checking method arguments. Java does handle this case inconsistently.- Specified by:
asJava
in interfaceSeq<T>
- Returns:
- A new immutable
Collection
view on thisTraversable
.
-
asJava
Description copied from interface:Seq
-
asJavaMutable
Description copied from interface:Seq
Creates a mutableList
view on top of thisSeq
, i.e. all mutator methods of theList
are implemented.- Specified by:
asJavaMutable
in interfaceSeq<T>
- Returns:
- A new mutable
Collection
view on thisTraversable
. - See Also:
-
asJavaMutable
Description copied from interface:Seq
- Specified by:
asJavaMutable
in interfaceLinearSeq<T>
- Specified by:
asJavaMutable
in interfaceSeq<T>
- Parameters:
action
- A side-effecting unit of work that operates on a mutablejava.util.List
view.- Returns:
- this instance, if only read operations are performed on the
java.util.List
view or a new instance of this type, if write operations are performed on thejava.util.List
view. - See Also:
-
collect
Description copied from interface:Traversable
Collects all elements that are in the domain of the givenpartialFunction
by mapping the elements to typeR
.More specifically, for each of this elements in iteration order first it is checked
If the elements makes it through that filter, the mapped instance is added to the result collectionpartialFunction.isDefinedAt(element)
Note:If thisR newElement = partialFunction.apply(element)
Traversable
is ordered (i.e. extendsOrdered
, the caller ofcollect
has to ensure that the elements are comparable (i.e. extendComparable
).- Specified by:
collect
in interfaceLinearSeq<T>
- Specified by:
collect
in interfaceSeq<T>
- Specified by:
collect
in interfaceTraversable<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 typeR
-
combinations
Description copied from interface:Seq
Returns the union of all combinations from k = 0 to length().Examples:
[].combinations() = [[]] [1,2,3].combinations() = [ [], // k = 0 [1], [2], [3], // k = 1 [1,2], [1,3], [2,3], // k = 2 [1,2,3] // k = 3 ]
- Specified by:
combinations
in interfaceLinearSeq<T>
- Specified by:
combinations
in interfaceSeq<T>
- Returns:
- the combinations of this
-
combinations
Description copied from interface:Seq
Returns the k-combination of this traversable, i.e. all subset of this of k distinct elements.- Specified by:
combinations
in interfaceLinearSeq<T>
- Specified by:
combinations
in interfaceSeq<T>
- Parameters:
k
- Size of subsets- Returns:
- the k-combination of this elements
- See Also:
-
crossProduct
Description copied from interface:Seq
Calculates the n-ary cartesian power (or cross product or simply product) of this.Example:
// = ((A,A), (A,B), (A,C), ..., (B,A), (B,B), ..., (Z,Y), (Z,Z)) CharSeq.rangeClosed('A', 'Z').crossProduct(2);
Cartesian power of negative value will return empty iterator.
Example:
// = () CharSeq.rangeClosed('A', 'Z').crossProduct(-1);
- Specified by:
crossProduct
in interfaceLinearSeq<T>
- Specified by:
crossProduct
in interfaceSeq<T>
- Parameters:
power
- the number of cartesian multiplications- Returns:
- A new Iterator representing the n-ary cartesian power of this
-
distinct
Description copied from interface:Traversable
Returns a new version of this which contains no duplicates. Elements are compared usingequals
. -
distinctBy
Description copied from interface:Traversable
Returns a new version of this which contains no duplicates. Elements are compared using the givencomparator
.- Specified by:
distinctBy
in interfaceLinearSeq<T>
- Specified by:
distinctBy
in interfaceSeq<T>
- Specified by:
distinctBy
in interfaceTraversable<T>
- Parameters:
comparator
- A comparator- Returns:
- a new
Traversable
containing this elements without duplicates
-
distinctBy
Description copied from interface:Traversable
Returns a new version of this which contains no duplicates. Elements mapped to keys which are compared usingequals
.The elements of the result are determined in the order of their occurrence - first match wins.
- Specified by:
distinctBy
in interfaceLinearSeq<T>
- Specified by:
distinctBy
in interfaceSeq<T>
- Specified by:
distinctBy
in interfaceTraversable<T>
- Type Parameters:
U
- key type- Parameters:
keyExtractor
- A key extractor- Returns:
- a new
Traversable
containing this elements without duplicates
-
drop
Description copied from interface:Traversable
Drops the first n elements of this or all elements, if this length < n.- Specified by:
drop
in interfaceLinearSeq<T>
- Specified by:
drop
in interfaceSeq<T>
- Specified by:
drop
in interfaceTraversable<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.
-
dropWhile
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 interfaceLinearSeq<T>
- Specified by:
dropWhile
in interfaceSeq<T>
- Specified by:
dropWhile
in interfaceTraversable<T>
- Specified by:
dropWhile
in classAbstractQueue<T,
Queue<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.
-
dropRight
Description copied from interface:Traversable
Drops the last n elements of this or all elements, if this length < n.- Specified by:
dropRight
in interfaceLinearSeq<T>
- Specified by:
dropRight
in interfaceSeq<T>
- Specified by:
dropRight
in interfaceTraversable<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.
-
dropRightUntil
Description copied from interface:Seq
Drops elements until the predicate holds for the current element, starting from the end.- Specified by:
dropRightUntil
in interfaceLinearSeq<T>
- Specified by:
dropRightUntil
in interfaceSeq<T>
- Parameters:
predicate
- A condition tested subsequently for this elements, starting from the end.- Returns:
- a new instance consisting of all elements until and including the last one which does satisfy the given predicate.
-
dropRightWhile
Description copied from interface:Seq
Drops elements while the predicate holds for the current element, starting from the end.Note: This is essentially the same as
dropRightUntil(predicate.negate())
. It is intended to be used with method references, which cannot be negated directly.- Specified by:
dropRightWhile
in interfaceLinearSeq<T>
- Specified by:
dropRightWhile
in interfaceSeq<T>
- Parameters:
predicate
- A condition tested subsequently for this elements, starting from the end.- Returns:
- a new instance consisting of all elements until and including the last one which does not satisfy the given predicate.
-
filter
Description copied from interface:Traversable
Returns a new traversable consisting of all elements which satisfy the given predicate. -
flatMap
Description copied from interface:Traversable
FlatMaps this Traversable. -
get
Description copied from interface:Seq
Returns the element at the specified index. -
groupBy
Description copied from interface:Traversable
Groups this elements by classifying the elements.- Specified by:
groupBy
in interfaceLinearSeq<T>
- Specified by:
groupBy
in interfaceSeq<T>
- Specified by:
groupBy
in interfaceTraversable<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:
-
grouped
Description copied from interface:Traversable
Groups thisTraversable
into fixed size blocks.Let length be the length of this Iterable. Then grouped is defined as follows:
- If
this.isEmpty()
, the resultingIterator
is empty. - If
size <= length
, the resultingIterator
will containlength / size
blocks of sizesize
and maybe a non-empty block of sizelength % size
, if there are remaining elements. - If
size > length
, the resultingIterator
will contain one block of sizelength
.
[].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]]
grouped(int)
is a special case of Traversable.sliding(int, int), i.e.grouped(size)
is the same assliding(size, size)
. - If
-
hasDefiniteSize
public boolean hasDefiniteSize()Description copied from interface:Traversable
Checks if this Traversable is known to have a finite size.This method should be implemented by classes only, i.e. not by interfaces.
- Specified by:
hasDefiniteSize
in interfaceTraversable<T>
- Returns:
- true, if this Traversable is known to have a finite size, false otherwise.
-
head
Description copied from interface:Traversable
Returns the first element of a non-empty Traversable.- Specified by:
head
in interfaceTraversable<T>
- Returns:
- The first element of this Traversable.
-
indexOf
Description copied from interface:Seq
Returns the index of the first occurrence of the given element after or at some start index or -1 if this does not contain the given element. -
init
Description copied from class:AbstractQueue
Dual of AbstractQueue.tail(), returning all elements except the last. -
insert
Description copied from interface:Seq
Inserts the given element at the specified index. -
insertAll
Description copied from interface:Seq
Inserts the given elements at the specified index. -
intersperse
Description copied from interface:Seq
Inserts an element between all elements of this Traversable.- Specified by:
intersperse
in interfaceLinearSeq<T>
- Specified by:
intersperse
in interfaceSeq<T>
- Parameters:
element
- An element.- Returns:
- an interspersed version of this
-
isAsync
public boolean isAsync()AQueue
is computed synchronously. -
isEmpty
public boolean isEmpty()Description copied from interface:Traversable
Checks if this Traversable is empty. -
isLazy
public boolean isLazy()AQueue
is computed eagerly. -
isTraversableAgain
public boolean isTraversableAgain()Description copied from interface:Traversable
Checks if this Traversable can be repeatedly traversed.This method should be implemented by classes only, i.e. not by interfaces.
- Specified by:
isTraversableAgain
in interfaceTraversable<T>
- Returns:
- true, if this Traversable is known to be traversable repeatedly, false otherwise.
-
last
Description copied from interface:Traversable
Dual of Traversable.head(), returning the last element.- Specified by:
last
in interfaceTraversable<T>
- Returns:
- the last element.
-
lastIndexOf
Description copied from interface:Seq
Returns the index of the last occurrence of the given element before or at a given end index or -1 if this does not contain the given element.- Specified by:
lastIndexOf
in interfaceSeq<T>
- Parameters:
element
- an elementend
- the end index- Returns:
- the index of the last occurrence of the given element
-
length
public int length()Description copied from interface:Traversable
Computes the number of elements of this Traversable.Same as
Traversable.size()
.- Specified by:
length
in interfaceTraversable<T>
- Returns:
- the number of elements
-
map
Description copied from interface:Traversable
Maps the elements of thisTraversable
to elements of a new type preserving their order, if any. -
orElse
Description copied from interface:Traversable
Returns thisTraversable
if it is nonempty, otherwise return the alternative. -
orElse
Description copied from interface:Traversable
Returns thisTraversable
if it is nonempty, otherwise return the result of evaluating supplier. -
padTo
Description copied from interface:Seq
A copy of this sequence with an element appended until a given target length is reached.Note: lazily-evaluated Seq implementations need to process all elements in order to gather the overall length.
- Specified by:
padTo
in interfaceLinearSeq<T>
- Specified by:
padTo
in interfaceSeq<T>
- Parameters:
length
- the target lengthelement
- the padding element- Returns:
- a new sequence consisting of all elements of this sequence followed by the minimal number
of occurrences of
element
so that the resulting sequence has a length of at leastlength
.
-
leftPadTo
Description copied from interface:Seq
A copy of this sequence with an element prepended until a given target length is reached.Note: lazily-evaluated Seq implementations need to process all elements in order to gather the overall length.
- Specified by:
leftPadTo
in interfaceSeq<T>
- Parameters:
length
- the target lengthelement
- the padding element- Returns:
- a new sequence consisting of all elements of this sequence prepended by the minimal number
of occurrences of
element
so that the resulting sequence has a length of at leastlength
.
-
patch
Description copied from interface:Seq
Produces a new list where a slice of elements in this list is replaced by another sequence. -
partition
Description copied from interface:Traversable
Creates a partition of thisTraversable
by splitting this elements in two in distinct traversables according to a predicate.- Specified by:
partition
in interfaceLinearSeq<T>
- Specified by:
partition
in interfaceSeq<T>
- Specified by:
partition
in interfaceTraversable<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 givenpredicate
, the secondTraversable
contains all elements that don't. The original order of elements is preserved.
-
permutations
Description copied from interface:Seq
Computes all unique permutations.Example:
[].permutations() = [] [1,2,3].permutations() = [ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1] ]
- Specified by:
permutations
in interfaceLinearSeq<T>
- Specified by:
permutations
in interfaceSeq<T>
- Returns:
- this unique permutations
-
prepend
Description copied from interface:Seq
Prepends an element to this. -
prependAll
Description copied from interface:Seq
Prepends all given elements to this.- Specified by:
prependAll
in interfaceLinearSeq<T>
- Specified by:
prependAll
in interfaceSeq<T>
- Parameters:
elements
- An Iterable of elements- Returns:
- A new Seq containing the given elements prepended to this elements
-
remove
Description copied from interface:Seq
Removes the first occurrence of the given element. -
removeFirst
Description copied from interface:Seq
Removes the first occurrence that satisfy predicate- Specified by:
removeFirst
in interfaceLinearSeq<T>
- Specified by:
removeFirst
in interfaceSeq<T>
- Parameters:
predicate
- an predicate- Returns:
- a new Seq
-
removeLast
Description copied from interface:Seq
Removes the last occurrence that satisfy predicate- Specified by:
removeLast
in interfaceLinearSeq<T>
- Specified by:
removeLast
in interfaceSeq<T>
- Parameters:
predicate
- an predicate- Returns:
- a new Seq
-
removeAt
Description copied from interface:Seq
Removes the element at the specified position in this sequence. Shifts any subsequent elements to the left (subtracts one from their indices). -
removeAll
Description copied from interface:Seq
Removes all occurrences of the given element. -
replace
Description copied from interface:Traversable
Replaces the first occurrence (if exists) of the given currentElement with newElement.- Specified by:
replace
in interfaceLinearSeq<T>
- Specified by:
replace
in interfaceSeq<T>
- Specified by:
replace
in interfaceTraversable<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
Description copied from interface:Traversable
Replaces all occurrences of the given currentElement with newElement.- Specified by:
replaceAll
in interfaceLinearSeq<T>
- Specified by:
replaceAll
in interfaceSeq<T>
- Specified by:
replaceAll
in interfaceTraversable<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.
-
reverse
Description copied from interface:Seq
Reverses the order of elements. -
rotateLeft
Description copied from interface:Seq
Circular rotates the elements by the specified distance to the left direction.// = List(3, 4, 5, 1, 2) List.of(1, 2, 3, 4, 5).rotateLeft(2);
- Specified by:
rotateLeft
in interfaceLinearSeq<T>
- Specified by:
rotateLeft
in interfaceSeq<T>
- Parameters:
n
- distance of left rotation- Returns:
- the rotated elements.
-
rotateRight
Description copied from interface:Seq
Circular rotates the elements by the specified distance to the right direction.// = List(4, 5, 1, 2, 3) List.of(1, 2, 3, 4, 5).rotateRight(2);
- Specified by:
rotateRight
in interfaceLinearSeq<T>
- Specified by:
rotateRight
in interfaceSeq<T>
- Parameters:
n
- distance of right rotation- Returns:
- the rotated elements.
-
scan
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 interfaceLinearSeq<T>
- Specified by:
scan
in interfaceSeq<T>
- Specified by:
scan
in interfaceTraversable<T>
- Parameters:
zero
- neutral element for the operator opoperation
- the associative operator for the scan- Returns:
- a new traversable collection containing the prefix scan of the elements in this traversable collection
-
scanLeft
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 interfaceLinearSeq<T>
- Specified by:
scanLeft
in interfaceSeq<T>
- Specified by:
scanLeft
in interfaceTraversable<T>
- Type Parameters:
U
- the type of the elements in the resulting collection- Parameters:
zero
- the initial valueoperation
- the binary operator applied to the intermediate result and the element- Returns:
- collection with intermediate results
-
scanRight
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 interfaceLinearSeq<T>
- Specified by:
scanRight
in interfaceSeq<T>
- Specified by:
scanRight
in interfaceTraversable<T>
- Type Parameters:
U
- the type of the elements in the resulting collection- Parameters:
zero
- the initial valueoperation
- the binary operator applied to the intermediate result and the element- Returns:
- collection with intermediate results
-
shuffle
Description copied from interface:Seq
Randomize the order of the elements in the current sequence. -
slice
Description copied from interface:Seq
Returns a Seq that is a slice of this. The slice begins with the element at the specifiedbeginIndex
and extends to the element at indexendIndex - 1
.Examples:
List.of(1, 2, 3, 4).slice(1, 3); // = (2, 3) List.of(1, 2, 3, 4).slice(0, 4); // = (1, 2, 3, 4) List.of(1, 2, 3, 4).slice(2, 2); // = () List.of(1, 2).slice(1, 0); // = () List.of(1, 2).slice(-10, 10); // = (1, 2)
Seq.subSequence(int, int)
which throws in some cases instead of returning a sequence. -
slideBy
Description copied from interface:Traversable
Slides a non-overlapping window of a variable size over thisTraversable
.Each window contains elements with the same class, as determined by
classifier
. Two consecutive values in thisTraversable
will be in the same window only ifclassifier
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]]
-
sliding
Description copied from interface:Traversable
Slides a window of a specificsize
and step size 1 over thisTraversable
by callingTraversable.sliding(int, int)
. -
sliding
Description copied from interface:Traversable
Slides a window of a specificsize
andstep
size over thisTraversable
.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]]
-
sorted
Description copied from interface:Seq
Sorts this elements according to their natural order. If this elements are notComparable
, ajava.lang.ClassCastException
may be thrown. -
sorted
Description copied from interface:Seq
Sorts this elements according to the providedComparator
. If this elements are notComparable
, ajava.lang.ClassCastException
may be thrown. -
sortBy
Description copied from interface:Seq
Sorts this elements by comparing the elements in a different domain, using the givenmapper
. -
sortBy
public <U> Queue<T> sortBy(Comparator<? super U> comparator, Function<? super T, ? extends U> mapper) Description copied from interface:Seq
Sorts this elements by comparing the elements in a different domain, using the givenmapper
. -
span
Description copied from interface:Traversable
Returns a tuple where the first element is the longest prefix of elements that satisfy the givenpredicate
and the second element is the remainder. -
splitAt
Description copied from interface:Seq
Splits a Seq at the specified index. The result ofsplitAt(n)
is equivalent toTuple.of(take(n), drop(n))
. -
splitAt
Description copied from interface:Seq
Splits a sequence at the first element which satisfies thePredicate
, e.g. Tuple(init, element+tail). -
splitAtInclusive
Description copied from interface:Seq
Splits a sequence at the first element which satisfies thePredicate
, e.g. Tuple(init+element, tail).- Specified by:
splitAtInclusive
in interfaceSeq<T>
- Parameters:
predicate
- An predicate- Returns:
- A
Tuple
containing divided sequences
-
startsWith
Description copied from interface:Seq
Tests whether this list contains the given sequence at a given index.Note: If the both the receiver object this and the argument that are infinite sequences this method may not terminate.
- Specified by:
startsWith
in interfaceSeq<T>
- Parameters:
that
- the sequence to testoffset
- the index where the sequence is searched.- Returns:
- true if that is empty or that is prefix of this collection starting from the given offset, false otherwise.
-
subSequence
Description copied from interface:Seq
Returns a Seq that is a subsequence of this. The subsequence begins with the element at the specifiedbeginIndex
and extends to the end of this Seq.Examples:
List.of(1, 2).subSequence(0); // = (1, 2) List.of(1, 2).subSequence(1); // = (2) List.of(1, 2).subSequence(2); // = () List.of(1, 2).subSequence(10); // throws IndexOutOfBoundsException List.of(1, 2).subSequence(-10); // throws IndexOutOfBoundsException
Seq.drop(int)
which is similar but does not throw.- Specified by:
subSequence
in interfaceLinearSeq<T>
- Specified by:
subSequence
in interfaceSeq<T>
- Parameters:
beginIndex
- the beginning index, inclusive- Returns:
- the specified subsequence
-
subSequence
Description copied from interface:Seq
Returns a Seq that is a subsequence of this. The subsequence begins with the element at the specifiedbeginIndex
and extends to the element at indexendIndex - 1
.Examples:
List.of(1, 2, 3, 4).subSequence(1, 3); // = (2, 3) List.of(1, 2, 3, 4).subSequence(0, 4); // = (1, 2, 3, 4) List.of(1, 2, 3, 4).subSequence(2, 2); // = () List.of(1, 2).subSequence(1, 0); // throws IndexOutOfBoundsException List.of(1, 2).subSequence(-10, 1); // throws IndexOutOfBoundsException List.of(1, 2).subSequence(0, 10); // throws IndexOutOfBoundsException
Seq.slice(int, int)
which returns an empty sequence instead of throwing.- Specified by:
subSequence
in interfaceLinearSeq<T>
- Specified by:
subSequence
in interfaceSeq<T>
- Parameters:
beginIndex
- the beginning index, inclusiveendIndex
- the end index, exclusive- Returns:
- the specified subsequence
-
tail
Description copied from class:AbstractQueue
Drops the first element of a non-empty Traversable. -
take
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 ifn < 0
orn > length()
.In the case of
n < 0
the empty instance is returned, in the case ofn > length()
this is returned. -
takeUntil
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 interfaceLinearSeq<T>
- Specified by:
takeUntil
in interfaceSeq<T>
- Specified by:
takeUntil
in interfaceTraversable<T>
- Specified by:
takeUntil
in classAbstractQueue<T,
Queue<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.
-
takeRight
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 ifn < 0
orn > length()
.In the case of
n < 0
the empty instance is returned, in the case ofn > length()
this is returned.- Specified by:
takeRight
in interfaceLinearSeq<T>
- Specified by:
takeRight
in interfaceSeq<T>
- Specified by:
takeRight
in interfaceTraversable<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.
-
takeRightUntil
Description copied from interface:Seq
Takes elements until the predicate holds for the current element, starting from the end.- Specified by:
takeRightUntil
in interfaceLinearSeq<T>
- Specified by:
takeRightUntil
in interfaceSeq<T>
- Parameters:
predicate
- A condition tested subsequently for this elements, starting from the end.- Returns:
- a new instance consisting of all elements after the last one which does satisfy the given predicate.
-
takeRightWhile
Description copied from interface:Seq
Takes elements while the predicate holds for the current element, starting from the end.Note: This is essentially the same as
takeRightUntil(predicate.negate())
. It is intended to be used with method references, which cannot be negated directly.- Specified by:
takeRightWhile
in interfaceLinearSeq<T>
- Specified by:
takeRightWhile
in interfaceSeq<T>
- Parameters:
predicate
- A condition tested subsequently for this elements, starting from the end.- Returns:
- a new instance consisting of all elements after the last one which does not satisfy the given predicate.
-
transform
Transforms thisQueue
.- Type Parameters:
U
- Type of transformation result- Parameters:
f
- A transformation- Returns:
- An instance of type
U
- Throws:
NullPointerException
- iff
is null
-
unzip
public <T1,T2> Tuple2<Queue<T1>,Queue<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 interfaceLinearSeq<T>
- Specified by:
unzip
in interfaceSeq<T>
- Specified by:
unzip
in interfaceTraversable<T>
- Type Parameters:
T1
- 1st element type of a pair returned by unzipperT2
- 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, Tuple3<Queue<T1>,T3> Queue<T2>, unzip3Queue<T3>> (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 interfaceSeq<T>
- Specified by:
unzip3
in interfaceTraversable<T>
- Type Parameters:
T1
- 1st element type of a triplet returned by unzipperT2
- 2nd element type of a triplet returned by unzipperT3
- 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
-
update
Description copied from interface:Seq
Updates the given element at the specified index. -
update
Description copied from interface:Seq
Updates the given element at the specified index using the specified function. -
zip
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 interfaceLinearSeq<T>
- Specified by:
zip
in interfaceSeq<T>
- Specified by:
zip
in interfaceTraversable<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> Queue<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 interfaceLinearSeq<T>
- Specified by:
zipWith
in interfaceSeq<T>
- Specified by:
zipWith
in interfaceTraversable<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
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 interfaceLinearSeq<T>
- Specified by:
zipAll
in interfaceSeq<T>
- Specified by:
zipAll
in interfaceTraversable<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
Description copied from interface:Traversable
Zips this traversable with its indices.- Specified by:
zipWithIndex
in interfaceLinearSeq<T>
- Specified by:
zipWithIndex
in interfaceSeq<T>
- Specified by:
zipWithIndex
in interfaceTraversable<T>
- Returns:
- A new traversable containing all elements of this traversable paired with their index, starting with 0.
-
zipWithIndex
Description copied from interface:Traversable
Zips this traversable with its indices by applying mapper provided.- Specified by:
zipWithIndex
in interfaceLinearSeq<T>
- Specified by:
zipWithIndex
in interfaceSeq<T>
- Specified by:
zipWithIndex
in interfaceTraversable<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.
-
readResolve
-
stringPrefix
Description copied from interface:Value
Returns the name of this Value type, which is used by toString().- Specified by:
stringPrefix
in interfaceValue<T>
- Returns:
- This type name.
-
equals
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)
- 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
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.
-
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:
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 = hash * 31 + Objects.hashCode(t); }
Please note that the particular hashing algorithms may change in a future version of Vavr.int hash = 1; for (T t : this) { hash += Objects.hashCode(t); }
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; } @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; } } @Override public int hashCode() { return hashCode.get(); } @Override public String toString() { return "Hashed(" + (key == null ? "null" : key.toString()) + ")"; } }
-