Class Spliterators.AbstractSpliterator<T>
- Type Parameters:
- T- the type of elements returned by this Spliterator
- All Implemented Interfaces:
- Spliterator<T>
- Enclosing class:
- Spliterators
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.
- API Note:
- This class is a useful aid for creating a spliterator when it is not
 possible or difficult to efficiently partition elements in a manner
 allowing balanced parallel computation.
 An alternative to using this class, that also permits limited parallelism, is to create a spliterator from an iterator (see Spliterators.spliterator(Iterator, long, int). Depending on the circumstances using an iterator may be easier or more convenient than extending this class, such as when there is already an iterator available to use.
- Since:
- 1.8
- See Also:
- 
Nested Class SummaryNested classes/interfaces declared in interface java.util.SpliteratorSpliterator.OfDouble, Spliterator.OfInt, Spliterator.OfLong, Spliterator.OfPrimitive<T, T_CONS, T_SPLITR extends Spliterator.OfPrimitive<T,T_CONS, T_SPLITR>> 
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Field SummaryFields declared in interface java.util.SpliteratorCONCURRENT, DISTINCT, IMMUTABLE, NONNULL, ORDERED, SIZED, SORTED, SUBSIZED
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Constructor SummaryConstructorsModifierConstructorDescriptionprotectedAbstractSpliterator(long est, int additionalCharacteristics) Creates a spliterator reporting the given estimated size and additionalCharacteristics.
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Method SummaryModifier and TypeMethodDescriptionintReturns a set of characteristics of this Spliterator and its elements.longReturns an estimate of the number of elements that would be encountered by aSpliterator.forEachRemaining(java.util.function.Consumer<? super T>)traversal, or returnsLong.MAX_VALUEif infinite, unknown, or too expensive to compute.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.Methods declared in class java.lang.Objectclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitMethods declared in interface java.util.SpliteratorforEachRemaining, getComparator, getExactSizeIfKnown, hasCharacteristics, tryAdvance
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Constructor Details- 
AbstractSpliteratorprotected AbstractSpliterator(long est, int additionalCharacteristics) Creates a spliterator reporting the given estimated size and additionalCharacteristics.- Parameters:
- est- the estimated size of this spliterator if known, otherwise- Long.MAX_VALUE.
- additionalCharacteristics- properties of this spliterator's source or elements. If- SIZEDis reported then this spliterator will additionally report- SUBSIZED.
 
 
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Method Details- 
trySplitIf 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 returnnull. Upon non-null return:- the value reported for estimateSize()before splitting, must, after splitting, be greater than or equal toestimateSize()for this and the returned Spliterator; and
- if this Spliterator is SUBSIZED, thenestimateSize()for this spliterator before splitting must be equal to the sum ofestimateSize()for this and the returned Spliterator after splitting.
 This method may return nullfor any reason, including emptiness, inability to split after traversal has commenced, data structure constraints, and efficiency considerations. This implementation permits limited parallelism.- Specified by:
- trySplitin interface- Spliterator<T>
- Returns:
- a Spliteratorcovering some portion of the elements, ornullif this spliterator cannot be split
 
- the value reported for 
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estimateSizepublic long estimateSize()Returns an estimate of the number of elements that would be encountered by aSpliterator.forEachRemaining(java.util.function.Consumer<? super T>)traversal, or returnsLong.MAX_VALUEif infinite, unknown, or too expensive to compute.If this Spliterator is Spliterator.SIZEDand has not yet been partially traversed or split, or this Spliterator isSpliterator.SUBSIZEDand 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 ofSpliterator.trySplit().- Specified by:
- estimateSizein interface- Spliterator<T>
- Implementation Requirements:
- This implementation returns the estimated size as reported when created and, if the estimate size is known, decreases in size when split.
- Returns:
- the estimated size, or Long.MAX_VALUEif infinite, unknown, or too expensive to compute.
 
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characteristicspublic int characteristics()Returns a set of characteristics of this Spliterator and its elements. The result is represented as ORed values fromSpliterator.ORDERED,Spliterator.DISTINCT,Spliterator.SORTED,Spliterator.SIZED,Spliterator.NONNULL,Spliterator.IMMUTABLE,Spliterator.CONCURRENT,Spliterator.SUBSIZED. Repeated calls tocharacteristics()on a given spliterator, prior to or in-between calls totrySplit, 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. - Specified by:
- characteristicsin interface- Spliterator<T>
- Implementation Requirements:
- This implementation returns the characteristics as reported when created.
- Returns:
- a representation of characteristics
 
 
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