scala.compat.java8.collectionImpl

Interface Stepper<A>

All Superinterfaces:

StepperLike<A,Stepper<A>>

All Known Subinterfaces:

AnyStepper<A>, DoubleStepper, IntStepper, LongStepper, NextStepper<A>, NextStepper$mcD$sp, NextStepper$mcI$sp, NextStepper$mcJ$sp, Stepper$mcD$sp, Stepper$mcI$sp, Stepper$mcJ$sp, TryStepper<A>, TryStepper$mcD$sp, TryStepper$mcI$sp, TryStepper$mcJ$sp

All Known Implementing Classes:

AccumulatorStepper, AnyStepper.BoxedDoubleStepper, AnyStepper.BoxedIntStepper, AnyStepper.BoxedLongStepper, DoubleAccumulatorStepper, IncStepperA, IncStepperB, IntAccumulatorStepper, LongAccumulatorStepper, MappingStepper, MappingStepper$mcDD$sp, MappingStepper$mcDI$sp, MappingStepper$mcDJ$sp, MappingStepper$mcID$sp, MappingStepper$mcII$sp, MappingStepper$mcIJ$sp, MappingStepper$mcJD$sp, MappingStepper$mcJI$sp, MappingStepper$mcJJ$sp, Stepper.OfDoubleSpliterator, Stepper.OfIntSpliterator, Stepper.OfLongSpliterator, Stepper.OfSpliterator, Stepper.UnboxingByteStepper, Stepper.UnboxingCharStepper, Stepper.UnboxingDoubleStepper, Stepper.UnboxingFloatStepper, Stepper.UnboxingIntStepper, Stepper.UnboxingLongStepper, Stepper.UnboxingShortStepper, StepperStringChar, StepperStringCodePoint, StepsAnyDefaultHashTable, StepsAnyDefaultHashTableValue, StepsAnyFlatHashTable, StepsAnyHashTableKey, StepsAnyImmHashMap, StepsAnyImmHashMapKey, StepsAnyImmHashMapValue, StepsAnyImmHashSet, StepsAnyIndexedSeq, StepsAnyIterator, StepsAnyLinearSeq, StepsAnyLinkedHashTable, StepsAnyLinkedHashTableValue, StepsAnyNumericRange, StepsAnyVector, StepsBoxedBooleanArray, StepsDoubleArray, StepsDoubleDefaultHashTableValue, StepsDoubleFlatHashTable, StepsDoubleHashTableKey, StepsDoubleImmHashMapKey, StepsDoubleImmHashMapValue, StepsDoubleImmHashSet, StepsDoubleIndexedSeq, StepsDoubleIterator, StepsDoubleLikeGapped, StepsDoubleLikeImmHashMap, StepsDoubleLikeIndexed, StepsDoubleLikeIterator, StepsDoubleLikeSliced, StepsDoubleLikeTrieIterator, StepsDoubleLinearSeq, StepsDoubleLinkedHashTableValue, StepsDoubleVector, StepsDoubleWithTail, StepsIntArray, StepsIntBitSet, StepsIntDefaultHashTableValue, StepsIntFlatHashTable, StepsIntHashTableKey, StepsIntImmHashMapKey, StepsIntImmHashMapValue, StepsIntImmHashSet, StepsIntIndexedSeq, StepsIntIterator, StepsIntLikeGapped, StepsIntLikeImmHashMap, StepsIntLikeIndexed, StepsIntLikeIterator, StepsIntLikeSliced, StepsIntLikeTrieIterator, StepsIntLinearSeq, StepsIntLinkedHashTableValue, StepsIntNumericRange, StepsIntRange, StepsIntVector, StepsIntWithTail, StepsLikeGapped, StepsLikeImmHashMap, StepsLikeIndexed, StepsLikeIterator, StepsLikeSliced, StepsLikeTrieIterator, StepsLongArray, StepsLongDefaultHashTableValue, StepsLongFlatHashTable, StepsLongHashTableKey, StepsLongImmHashMapKey, StepsLongImmHashMapValue, StepsLongImmHashSet, StepsLongIndexedSeq, StepsLongIterator, StepsLongLikeGapped, StepsLongLikeImmHashMap, StepsLongLikeIndexed, StepsLongLikeIterator, StepsLongLikeSliced, StepsLongLikeTrieIterator, StepsLongLinearSeq, StepsLongLinkedHashTableValue, StepsLongNumericRange, StepsLongVector, StepsLongWithTail, StepsObjectArray, StepsWidenedByteArray, StepsWidenedCharArray, StepsWidenedFloatArray, StepsWidenedShortArray, StepsWithTail

public interface Stepper<A>
extends StepperLike<A,Stepper<A>>

A Stepper is a specialized collection that can step through its contents once. It provides the same test-and-get methods as does Iterator, named hasStep and nextStep so they can coexist with iterator methods. However, like Spliterator, steppers provide a tryStep method to call a closure if another element exists, a substep() method to split into pieces, and characteristics and size-reporting methods that implement the subdivision and report what is known about the remaining size of the Stepper. Stepper thus naturally implements both Iterator and Spliterator.

A Stepper can present itself as a Spliterator via the spliterator method, or as a Scala Iterator via the iterator method. The Stepper trait is compatible with both Spliterator and Java's generic and primitive iterators, so a Stepper may already be one or both.

Subtraits NextStepper and TryStepper fill in the basic capability by either implementing tryStep in terms of hasStep and nextStep, or vice versa.

Subtraits AnyStepper, DoubleStepper, IntStepper, and LongStepper implement both the Stepper trait and the corresponding Java Spliterator and Iterator/PrimitiveIterator.

Example:

 val s = Stepper.of(Vector(1,2,3,4))
 if (s.hasStep) println(s.nextStep)      //  Prints 1
 println(s.tryStep(i => println(i*i)))   //  Prints 4, then true
 s.substep.foreach(println)              //  Prints 3
 println(s.count(_ > 3))                 //  Prints 4
 println(s.hasStep)                      //  Prints `false`
 

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Stepper.OfDoubleSpliterator
static class	Stepper.OfIntSpliterator
static class	Stepper.OfLongSpliterator
static class	Stepper.OfSpliterator<A>
static class	Stepper.UnboxingByteStepper
static class	Stepper.UnboxingCharStepper
static class	Stepper.UnboxingDoubleStepper
static class	Stepper.UnboxingFloatStepper
static class	Stepper.UnboxingIntStepper
static class	Stepper.UnboxingLongStepper
static class	Stepper.UnboxingShortStepper

Method Summary

Modifier and Type	Method and Description
<Acc extends AccumulatorLike<A,Acc>> Acc	accumulate(AccumulatesFromStepper<A,Acc> accer) Drains the contents of this stepper into an Accumulator or specialized variant thereof as appropriate.

Methods inherited from interface scala.compat.java8.collectionImpl.StepperLike

anticipateParallelism, characteristics, count, count, exists, find, fold, foldTo, foreach, hasStep, iterator, knownSize, nextStep, reduce, spliterator, substep, to, tryStep

Method Detail

accumulate

<Acc extends AccumulatorLike<A,Acc>> Acc accumulate(AccumulatesFromStepper<A,Acc> accer)

Drains the contents of this stepper into an Accumulator or specialized variant thereof as appropriate. This is a terminal operation.

Note: accumulation will occur sequentially. To accumulate in parallel, use a Stream (i.e. .parStream.accumulate).

Parameters:

accer - (undocumented)

Returns:

(undocumented)