Added in API level 24

AbstractSpliterator

abstract class AbstractSpliterator<T : Any!> : Spliterator<T>

kotlin.Any
↳	java.util.Spliterators.AbstractSpliterator

An abstract Spliterator that implements trySplit to permit limited parallelism.

An extending class need only implement tryAdvance. The extending class should override forEachRemaining if it can provide a more performant implementation.

Summary

Inherited constants

From class Spliterator Int CONCURRENT Characteristic value signifying that the element source may be safely concurrently modified (allowing additions, replacements, and/or removals) by multiple threads without external synchronization. If so, the Spliterator is expected to have a documented policy concerning the impact of modifications during traversal. A top-level Spliterator should not report both CONCURRENT and SIZED, since the finite size, if known, may change if the source is concurrently modified during traversal. Such a Spliterator is inconsistent and no guarantees can be made about any computation using that Spliterator. Sub-spliterators may report SIZED if the sub-split size is known and additions or removals to the source are not reflected when traversing. A top-level Spliterator should not report both CONCURRENT and IMMUTABLE, since they are mutually exclusive. Such a Spliterator is inconsistent and no guarantees can be made about any computation using that Spliterator. Sub-spliterators may report IMMUTABLE if additions or removals to the source are not reflected when traversing. Int DISTINCT Characteristic value signifying that, for each pair of encountered elements x, y, !x.equals(y). This applies for example, to a Spliterator based on a Set. Int IMMUTABLE Characteristic value signifying that the element source cannot be structurally modified; that is, elements cannot be added, replaced, or removed, so such changes cannot occur during traversal. A Spliterator that does not report IMMUTABLE or CONCURRENT is expected to have a documented policy (for example throwing ConcurrentModificationException) concerning structural interference detected during traversal. Int NONNULL Characteristic value signifying that the source guarantees that encountered elements will not be null. (This applies, for example, to most concurrent collections, queues, and maps.) Int ORDERED Characteristic value signifying that an encounter order is defined for elements. If so, this Spliterator guarantees that method trySplit splits a strict prefix of elements, that method tryAdvance steps by one element in prefix order, and that forEachRemaining performs actions in encounter order. A Collection has an encounter order if the corresponding Collection.iterator documents an order. If so, the encounter order is the same as the documented order. Otherwise, a collection does not have an encounter order. Int SIZED Characteristic value signifying that the value returned from estimateSize() prior to traversal or splitting represents a finite size that, in the absence of structural source modification, represents an exact count of the number of elements that would be encountered by a complete traversal. Int SORTED Characteristic value signifying that encounter order follows a defined sort order. If so, method getComparator() returns the associated Comparator, or null if all elements are Comparable and are sorted by their natural ordering. A Spliterator that reports SORTED must also report ORDERED. Int SUBSIZED Characteristic value signifying that all Spliterators resulting from trySplit() will be both SIZED and SUBSIZED. (This means that all child Spliterators, whether direct or indirect, will be SIZED.) A Spliterator that does not report SIZED as required by SUBSIZED is inconsistent and no guarantees can be made about any computation using that Spliterator.

Protected constructors
AbstractSpliterator(est: Long, additionalCharacteristics: Int) Creates a spliterator reporting the given estimated size and additionalCharacteristics.

Public methods
open Int	characteristics() Returns a set of characteristics of this Spliterator and its elements.
open Long	estimateSize() Returns an estimate of the number of elements that would be encountered by a forEachRemaining traversal, or returns java.lang.Long#MAX_VALUE if infinite, unknown, or too expensive to compute.
open Spliterator<T>!	trySplit() If this spliterator can be partitioned, returns a Spliterator covering elements, that will, upon return from this method, not be covered by this Spliterator.

Inherited functions

From class Spliterator Unit forEachRemaining(action: Consumer<in T>!) Performs the given action for each remaining element, sequentially in the current thread, until all elements have been processed or the action throws an exception. If this Spliterator is ORDERED, actions are performed in encounter order. Exceptions thrown by the action are relayed to the caller. Subsequent behavior of a spliterator is unspecified if the action throws an exception. Comparator<in T>! getComparator() If this Spliterator's source is SORTED by a Comparator, returns that Comparator. If the source is SORTED in natural order, returns null. Otherwise, if the source is not SORTED, throws IllegalStateException. Long getExactSizeIfKnown() Convenience method that returns estimateSize() if this Spliterator is SIZED, else -1. Boolean hasCharacteristics(characteristics: Int) Returns true if this Spliterator's characteristics contain all of the given characteristics. Boolean tryAdvance(action: Consumer<in T>!) If a remaining element exists: performs the given action on it, returning true; else returns false. If this Spliterator is ORDERED the action is performed on the next element in encounter order. Exceptions thrown by the action are relayed to the caller. Subsequent behavior of a spliterator is unspecified if the action throws an exception.

Protected constructors

AbstractSpliterator

Added in API level 24

protected AbstractSpliterator(
    est: Long, 
    additionalCharacteristics: Int)

Creates a spliterator reporting the given estimated size and additionalCharacteristics.

Parameters
est	Long: the estimated size of this spliterator if known, otherwise Long.MAX_VALUE.
additionalCharacteristics	Int: properties of this spliterator's source or elements. If SIZED is reported then this spliterator will additionally report SUBSIZED.

Public methods

characteristics

Added in API level 24

open fun characteristics(): Int

Returns a set of characteristics of this Spliterator and its elements. The result is represented as ORed values from ORDERED, DISTINCT, SORTED, SIZED, NONNULL, IMMUTABLE, CONCURRENT, SUBSIZED. Repeated calls to characteristics() on a given spliterator, prior to or in-between calls to trySplit, should always return the same result.

If a Spliterator reports an inconsistent set of characteristics (either those returned from a single invocation or across multiple invocations), no guarantees can be made about any computation using this Spliterator.

Return
Int	a representation of characteristics

estimateSize

Added in API level 24

open fun estimateSize(): Long

Returns an estimate of the number of elements that would be encountered by a forEachRemaining traversal, or returns java.lang.Long#MAX_VALUE if infinite, unknown, or too expensive to compute.

If this Spliterator is SIZED and has not yet been partially traversed or split, or this Spliterator is SUBSIZED and has not yet been partially traversed, this estimate must be an accurate count of elements that would be encountered by a complete traversal. Otherwise, this estimate may be arbitrarily inaccurate, but must decrease as specified across invocations of trySplit.

Return
Long	the estimated size, or Long.MAX_VALUE if infinite, unknown, or too expensive to compute.

trySplit

Added in API level 24

open fun trySplit(): Spliterator<T>!

If this spliterator can be partitioned, returns a Spliterator covering elements, that will, upon return from this method, not be covered by this Spliterator.

If this Spliterator is ORDERED, the returned Spliterator must cover a strict prefix of the elements.

Unless this Spliterator covers an infinite number of elements, repeated calls to trySplit() must eventually return null. Upon non-null return:

• the value reported for estimateSize() before splitting, must, after splitting, be greater than or equal to estimateSize() for this and the returned Spliterator; and
• if this Spliterator is SUBSIZED, then estimateSize() for this spliterator before splitting must be equal to the sum of estimateSize() for this and the returned Spliterator after splitting.

This method may return null for any reason, including emptiness, inability to split after traversal has commenced, data structure constraints, and efficiency considerations. This implementation permits limited parallelism.

Return
Spliterator<T>!	a Spliterator covering some portion of the elements, or null if this spliterator cannot be split