public abstract static class Spliterators.AbstractDoubleSpliterator extends Object implements Spliterator.OfDouble
An abstract Spliterator.OfDouble
that implements trySplit
to permit limited parallelism.
To implement a spliterator an extending class need only implement Spliterator.OfDouble.tryAdvance(java.util.function.DoubleConsumer)
tryAdvance}. The extending class should override Spliterator.OfDouble.forEachRemaining(java.util.function.DoubleConsumer)
forEach} if it can provide a more performant implementation.
An alternative to using this class, that also permits limited parallelism, is to create a spliterator from an iterator (see Spliterators.spliterator(java.util.PrimitiveIterator.OfDouble, long, int)
. Depending on the circumstances using an iterator may be easier or more convenient than extending this class. For example, if there is already an iterator available to use then there is no need to extend this class.
Spliterators.spliterator(java.util.PrimitiveIterator.OfDouble, long, int)
Spliterator.OfDouble, Spliterator.OfInt, Spliterator.OfLong, Spliterator.OfPrimitive<T,T_CONS,T_SPLITR extends Spliterator.OfPrimitive<T,T_CONS,T_SPLITR>>
CONCURRENT, DISTINCT, IMMUTABLE, NONNULL, ORDERED, SIZED, SORTED, SUBSIZED
protected AbstractDoubleSpliterator(long est, int additionalCharacteristics)
Creates a spliterator reporting the given estimated size and characteristics.
est
- the estimated size of this spliterator if known, otherwise Long.MAX_VALUE
.additionalCharacteristics
- properties of this spliterator's source or elements. If SIZED
is reported then this spliterator will additionally report SUBSIZED
.public Spliterator.OfDouble 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.
If this Spliterator is Spliterator.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:
estimateSize()
before splitting, must, after splitting, be greater than or equal to estimateSize()
for this and the returned Spliterator; andSUBSIZED
, 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.
trySplit
in interface Spliterator<Double>
trySplit
in interface Spliterator.OfDouble
trySplit
in interface Spliterator.OfPrimitive<Double,DoubleConsumer,Spliterator.OfDouble>
Spliterator
covering some portion of the elements, or null
if this spliterator cannot be splitpublic long estimateSize()
Returns an estimate of the number of elements that would be encountered by a Spliterator.forEachRemaining(java.util.function.Consumer<? super T>)
traversal, or returns Long.MAX_VALUE
if infinite, unknown, or too expensive to compute.
If this Spliterator is Spliterator.SIZED
and has not yet been partially traversed or split, or this Spliterator is Spliterator.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 Spliterator.trySplit()
.
estimateSize
in interface Spliterator<Double>
Long.MAX_VALUE
if infinite, unknown, or too expensive to compute.public int characteristics()
Returns a set of characteristics of this Spliterator and its elements. The result is represented as ORed values from Spliterator.ORDERED
, Spliterator.DISTINCT
, Spliterator.SORTED
, Spliterator.SIZED
, Spliterator.NONNULL
, Spliterator.IMMUTABLE
, Spliterator.CONCURRENT
, Spliterator.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.
characteristics
in interface Spliterator<Double>
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