Stepper

scala.collection.Stepper
See theStepper companion object
trait Stepper[+A]

Steppers exist to enable creating Java streams over Scala collections, see scala.jdk.StreamConverters. Besides that use case, they allow iterating over collections holding unboxed primitives (e.g., Array[Int]) without boxing the elements.

Steppers have an iterator-like interface with methods hasStep and nextStep(). The difference to iterators - and the reason Stepper is not a subtype of Iterator - is that there are hand-specialized variants of Stepper for Int, Long and Double (IntStepper, etc.). These enable iterating over collections holding unboxed primitives (e.g., Arrays, scala.jdk.Accumulators) without boxing the elements.

The selection of primitive types (Int, Long and Double) matches the hand-specialized variants of Java Streams (java.util.stream.Stream, java.util.stream.IntStream, etc.) and the corresponding Java Spliterators (java.util.Spliterator, java.util.Spliterator.OfInt, etc.).

Steppers can be converted to Scala Iterators, Java Iterators and Java Spliterators. Primitive Steppers are converted to the corresponding primitive Java Iterators and Spliterators.

Attributes

A

the element type of the Stepper

Companion:
object
Source:
Stepper.scala
Graph
Supertypes
class Object
trait Matchable
class Any
Known subtypes

Members list

Concise view

Value members

Abstract methods

Returns a set of characteristics of this Stepper and its elements.

Returns a set of characteristics of this Stepper and its elements. See method characteristics in java.util.Spliterator.

Attributes

Source:
Stepper.scala

Returns an estimate of the number of elements of this Stepper, or Long.MaxValue.

Returns an estimate of the number of elements of this Stepper, or Long.MaxValue. See method estimateSize in java.util.Spliterator.

Attributes

Source:
Stepper.scala

Check if there's an element available.

Check if there's an element available.

Attributes

Source:
Stepper.scala
def javaIterator[B >: A]: Iterator[_]

Returns a Java java.util.Iterator corresponding to this Stepper.

Returns a Java java.util.Iterator corresponding to this Stepper.

Note that the return type is Iterator[_] instead of Iterator[A] to allow returning a java.util.PrimitiveIterator.OfInt (which is a Iterator[Integer]) in the subclass IntStepper (which is a Stepper[Int]).

Attributes

Source:
Stepper.scala
def nextStep(): A

Return the next element and advance the stepper

Return the next element and advance the stepper

Attributes

Source:
Stepper.scala
def spliterator[B >: A]: Spliterator[_]

Returns a java.util.Spliterator corresponding to this Stepper.

Returns a java.util.Spliterator corresponding to this Stepper.

Note that the return type is Spliterator[_] instead of Spliterator[A] to allow returning a java.util.Spliterator.OfInt (which is a Spliterator[Integer]) in the subclass IntStepper (which is a Stepper[Int]).

Attributes

Source:
Stepper.scala
def trySplit(): Stepper[A]

Split this stepper, if applicable.

Split this stepper, if applicable. The elements of the current Stepper are split up between the resulting Stepper and the current stepper.

May return null, in which case the current Stepper yields the same elements as before.

See method trySplit in java.util.Spliterator.

Attributes

Source:
Stepper.scala

Concrete methods

Returns an Iterator corresponding to this Stepper.

Returns an Iterator corresponding to this Stepper. Note that Iterators corresponding to primitive Steppers box the elements.

Attributes

Source:
Stepper.scala