Module java.base
Package java.util

# Class Spliterators

java.lang.Object
java.util.Spliterators

public final class Spliterators extends Object
Static classes and methods for operating on or creating instances of `Spliterator` and its primitive specializations `Spliterator.OfInt`, `Spliterator.OfLong`, and `Spliterator.OfDouble`.

Since:
  1.8
See Also:
  - `Spliterator`

- ## Nested Class Summary

  Nested Classes
  Modifier and Type
  Class
  Description
  `static class`
  `Spliterators.AbstractDoubleSpliterator`
  An abstract `Spliterator.OfDouble` that implements `trySplit` to permit limited parallelism.
  `static class`
  `Spliterators.AbstractIntSpliterator`
  An abstract `Spliterator.OfInt` that implements `trySplit` to permit limited parallelism.
  `static class`
  `Spliterators.AbstractLongSpliterator`
  An abstract `Spliterator.OfLong` that implements `trySplit` to permit limited parallelism.
  `static class`
  `Spliterators.AbstractSpliterator<T>`
  An abstract `Spliterator` that implements `trySplit` to permit limited parallelism.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static Spliterator.OfDouble`
  `emptyDoubleSpliterator()`
  Creates an empty `Spliterator.OfDouble`
  `static Spliterator.OfInt`
  `emptyIntSpliterator()`
  Creates an empty `Spliterator.OfInt`
  `static Spliterator.OfLong`
  `emptyLongSpliterator()`
  Creates an empty `Spliterator.OfLong`
  `static <T> Spliterator<T>`
  `emptySpliterator()`
  Creates an empty `Spliterator`
  `static PrimitiveIterator.OfDouble`
  `iterator(Spliterator.OfDouble spliterator)`
  Creates an `PrimitiveIterator.OfDouble` from a `Spliterator.OfDouble`.
  `static PrimitiveIterator.OfInt`
  `iterator(Spliterator.OfInt spliterator)`
  Creates an `PrimitiveIterator.OfInt` from a `Spliterator.OfInt`.
  `static PrimitiveIterator.OfLong`
  `iterator(Spliterator.OfLong spliterator)`
  Creates an `PrimitiveIterator.OfLong` from a `Spliterator.OfLong`.
  `static <T> Iterator<T>`
  `iterator(Spliterator<? extends T> spliterator)`
  Creates an `Iterator` from a `Spliterator`.
  `static Spliterator.OfDouble`
  `spliterator(double[] array, int additionalCharacteristics)`
  Creates a `Spliterator.OfDouble` covering the elements of a given array, using a customized set of spliterator characteristics.
  `static Spliterator.OfDouble`
  `spliterator(double[] array, int fromIndex, int toIndex, int additionalCharacteristics)`
  Creates a `Spliterator.OfDouble` covering a range of elements of a given array, using a customized set of spliterator characteristics.
  `static Spliterator.OfInt`
  `spliterator(int[] array, int additionalCharacteristics)`
  Creates a `Spliterator.OfInt` covering the elements of a given array, using a customized set of spliterator characteristics.
  `static Spliterator.OfInt`
  `spliterator(int[] array, int fromIndex, int toIndex, int additionalCharacteristics)`
  Creates a `Spliterator.OfInt` covering a range of elements of a given array, using a customized set of spliterator characteristics.
  `static Spliterator.OfLong`
  `spliterator(long[] array, int additionalCharacteristics)`
  Creates a `Spliterator.OfLong` covering the elements of a given array, using a customized set of spliterator characteristics.
  `static Spliterator.OfLong`
  `spliterator(long[] array, int fromIndex, int toIndex, int additionalCharacteristics)`
  Creates a `Spliterator.OfLong` covering a range of elements of a given array, using a customized set of spliterator characteristics.
  `static <T> Spliterator<T>`
  `spliterator(Object[] array, int additionalCharacteristics)`
  Creates a `Spliterator` covering the elements of a given array, using a customized set of spliterator characteristics.
  `static <T> Spliterator<T>`
  `spliterator(Object[] array, int fromIndex, int toIndex, int additionalCharacteristics)`
  Creates a `Spliterator` covering a range of elements of a given array, using a customized set of spliterator characteristics.
  `static <T> Spliterator<T>`
  `spliterator(Collection<? extends T> c, int characteristics)`
  Creates a `Spliterator` using the given collection's `iterator` as the source of elements, and reporting its `size` as its initial size.
  `static <T> Spliterator<T>`
  `spliterator(Iterator<? extends T> iterator, long size, int characteristics)`
  Creates a `Spliterator` using a given `Iterator` as the source of elements, and with a given initially reported size.
  `static Spliterator.OfDouble`
  `spliterator(PrimitiveIterator.OfDouble iterator, long size, int characteristics)`
  Creates a `Spliterator.OfDouble` using a given `DoubleStream.DoubleIterator` as the source of elements, and with a given initially reported size.
  `static Spliterator.OfInt`
  `spliterator(PrimitiveIterator.OfInt iterator, long size, int characteristics)`
  Creates a `Spliterator.OfInt` using a given `IntStream.IntIterator` as the source of elements, and with a given initially reported size.
  `static Spliterator.OfLong`
  `spliterator(PrimitiveIterator.OfLong iterator, long size, int characteristics)`
  Creates a `Spliterator.OfLong` using a given `LongStream.LongIterator` as the source of elements, and with a given initially reported size.
  `static <T> Spliterator<T>`
  `spliteratorUnknownSize(Iterator<? extends T> iterator, int characteristics)`
  Creates a `Spliterator` using a given `Iterator` as the source of elements, with no initial size estimate.
  `static Spliterator.OfDouble`
  `spliteratorUnknownSize(PrimitiveIterator.OfDouble iterator, int characteristics)`
  Creates a `Spliterator.OfDouble` using a given `DoubleStream.DoubleIterator` as the source of elements, with no initial size estimate.
  `static Spliterator.OfInt`
  `spliteratorUnknownSize(PrimitiveIterator.OfInt iterator, int characteristics)`
  Creates a `Spliterator.OfInt` using a given `IntStream.IntIterator` as the source of elements, with no initial size estimate.
  `static Spliterator.OfLong`
  `spliteratorUnknownSize(PrimitiveIterator.OfLong iterator, int characteristics)`
  Creates a `Spliterator.OfLong` using a given `LongStream.LongIterator` as the source of elements, with no initial size estimate.

  ### Methods declared in class java.lang.Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Method Details

  - ### emptySpliterator

    public static <T> Spliterator<T> emptySpliterator()
    Creates an empty `Spliterator`

    The empty spliterator reports `Spliterator.SIZED` and `Spliterator.SUBSIZED`. Calls to `Spliterator.trySplit()` always return `null`.

    Type Parameters:
      `T` - Type of elements
    Returns:
      An empty spliterator

  - ### emptyIntSpliterator

    public static Spliterator.OfInt emptyIntSpliterator()
    Creates an empty `Spliterator.OfInt`

    The empty spliterator reports `Spliterator.SIZED` and `Spliterator.SUBSIZED`. Calls to `Spliterator.trySplit()` always return `null`.

    Returns:
      An empty spliterator

  - ### emptyLongSpliterator

    public static Spliterator.OfLong emptyLongSpliterator()
    Creates an empty `Spliterator.OfLong`

    The empty spliterator reports `Spliterator.SIZED` and `Spliterator.SUBSIZED`. Calls to `Spliterator.trySplit()` always return `null`.

    Returns:
      An empty spliterator

  - ### emptyDoubleSpliterator

    public static Spliterator.OfDouble emptyDoubleSpliterator()
    Creates an empty `Spliterator.OfDouble`

    The empty spliterator reports `Spliterator.SIZED` and `Spliterator.SUBSIZED`. Calls to `Spliterator.trySplit()` always return `null`.

    Returns:
      An empty spliterator

  - ### spliterator

    public static <T> Spliterator<T> spliterator(Object[] array, int additionalCharacteristics)
    Creates a `Spliterator` covering the elements of a given array, using a customized set of spliterator characteristics.

    This method is provided as an implementation convenience for Spliterators which store portions of their elements in arrays, and need fine control over Spliterator characteristics. Most other situations in which a Spliterator for an array is needed should use `Arrays.spliterator(Object[])`.

    The returned spliterator always reports the characteristics `SIZED` and `SUBSIZED`. The caller may provide additional characteristics for the spliterator to report; it is common to additionally specify `IMMUTABLE` and `ORDERED`.

    Type Parameters:
      `T` - Type of elements
    Parameters:
      `array` - The array, assumed to be unmodified during use
      `additionalCharacteristics` - Additional spliterator characteristics of this spliterator's source or elements beyond `SIZED` and `SUBSIZED` which are always reported
    Returns:
      A spliterator for an array
    Throws:
      `NullPointerException` - if the given array is `null`
    See Also:
      - `Arrays.spliterator(Object[])`

  - ### spliterator

    public static <T> Spliterator<T> spliterator(Object[] array, int fromIndex, int toIndex, int additionalCharacteristics)
    Creates a `Spliterator` covering a range of elements of a given array, using a customized set of spliterator characteristics.

    This method is provided as an implementation convenience for Spliterators which store portions of their elements in arrays, and need fine control over Spliterator characteristics. Most other situations in which a Spliterator for an array is needed should use `Arrays.spliterator(Object[])`.

    The returned spliterator always reports the characteristics `SIZED` and `SUBSIZED`. The caller may provide additional characteristics for the spliterator to report; it is common to additionally specify `IMMUTABLE` and `ORDERED`.

    Type Parameters:
      `T` - Type of elements
    Parameters:
      `array` - The array, assumed to be unmodified during use
      `fromIndex` - The least index (inclusive) to cover
      `toIndex` - One past the greatest index to cover
      `additionalCharacteristics` - Additional spliterator characteristics of this spliterator's source or elements beyond `SIZED` and `SUBSIZED` which are always reported
    Returns:
      A spliterator for an array
    Throws:
      `NullPointerException` - if the given array is `null`
      `ArrayIndexOutOfBoundsException` - if `fromIndex` is negative, `toIndex` is less than `fromIndex`, or `toIndex` is greater than the array size
    See Also:
      - `Arrays.spliterator(Object[], int, int)`

  - ### spliterator

    public static Spliterator.OfInt spliterator(int[] array, int additionalCharacteristics)
    Creates a `Spliterator.OfInt` covering the elements of a given array, using a customized set of spliterator characteristics.

    This method is provided as an implementation convenience for Spliterators which store portions of their elements in arrays, and need fine control over Spliterator characteristics. Most other situations in which a Spliterator for an array is needed should use `Arrays.spliterator(int[])`.

    The returned spliterator always reports the characteristics `SIZED` and `SUBSIZED`. The caller may provide additional characteristics for the spliterator to report; it is common to additionally specify `IMMUTABLE` and `ORDERED`.

    Parameters:
      `array` - The array, assumed to be unmodified during use
      `additionalCharacteristics` - Additional spliterator characteristics of this spliterator's source or elements beyond `SIZED` and `SUBSIZED` which are always reported
    Returns:
      A spliterator for an array
    Throws:
      `NullPointerException` - if the given array is `null`
    See Also:
      - `Arrays.spliterator(int[])`

  - ### spliterator

    public static Spliterator.OfInt spliterator(int[] array, int fromIndex, int toIndex, int additionalCharacteristics)
    Creates a `Spliterator.OfInt` covering a range of elements of a given array, using a customized set of spliterator characteristics.

    This method is provided as an implementation convenience for Spliterators which store portions of their elements in arrays, and need fine control over Spliterator characteristics. Most other situations in which a Spliterator for an array is needed should use `Arrays.spliterator(int[], int, int)`.

    The returned spliterator always reports the characteristics `SIZED` and `SUBSIZED`. The caller may provide additional characteristics for the spliterator to report; it is common to additionally specify `IMMUTABLE` and `ORDERED`.

    Parameters:
      `array` - The array, assumed to be unmodified during use
      `fromIndex` - The least index (inclusive) to cover
      `toIndex` - One past the greatest index to cover
      `additionalCharacteristics` - Additional spliterator characteristics of this spliterator's source or elements beyond `SIZED` and `SUBSIZED` which are always reported
    Returns:
      A spliterator for an array
    Throws:
      `NullPointerException` - if the given array is `null`
      `ArrayIndexOutOfBoundsException` - if `fromIndex` is negative, `toIndex` is less than `fromIndex`, or `toIndex` is greater than the array size
    See Also:
      - `Arrays.spliterator(int[], int, int)`

  - ### spliterator

    public static Spliterator.OfLong spliterator(long[] array, int additionalCharacteristics)
    Creates a `Spliterator.OfLong` covering the elements of a given array, using a customized set of spliterator characteristics.

    This method is provided as an implementation convenience for Spliterators which store portions of their elements in arrays, and need fine control over Spliterator characteristics. Most other situations in which a Spliterator for an array is needed should use `Arrays.spliterator(long[])`.

    The returned spliterator always reports the characteristics `SIZED` and `SUBSIZED`. The caller may provide additional characteristics for the spliterator to report; it is common to additionally specify `IMMUTABLE` and `ORDERED`.

    Parameters:
      `array` - The array, assumed to be unmodified during use
      `additionalCharacteristics` - Additional spliterator characteristics of this spliterator's source or elements beyond `SIZED` and `SUBSIZED` which are always reported
    Returns:
      A spliterator for an array
    Throws:
      `NullPointerException` - if the given array is `null`
    See Also:
      - `Arrays.spliterator(long[])`

  - ### spliterator

    public static Spliterator.OfLong spliterator(long[] array, int fromIndex, int toIndex, int additionalCharacteristics)
    Creates a `Spliterator.OfLong` covering a range of elements of a given array, using a customized set of spliterator characteristics.

    This method is provided as an implementation convenience for Spliterators which store portions of their elements in arrays, and need fine control over Spliterator characteristics. Most other situations in which a Spliterator for an array is needed should use `Arrays.spliterator(long[], int, int)`.

    The returned spliterator always reports the characteristics `SIZED` and `SUBSIZED`. The caller may provide additional characteristics for the spliterator to report. (For example, if it is known the array will not be further modified, specify `IMMUTABLE`; if the array data is considered to have an encounter order, specify `ORDERED`). The method `Arrays.spliterator(long[], int, int)` can often be used instead, which returns a spliterator that reports `SIZED`, `SUBSIZED`, `IMMUTABLE`, and `ORDERED`.

    Parameters:
      `array` - The array, assumed to be unmodified during use
      `fromIndex` - The least index (inclusive) to cover
      `toIndex` - One past the greatest index to cover
      `additionalCharacteristics` - Additional spliterator characteristics of this spliterator's source or elements beyond `SIZED` and `SUBSIZED` which are always reported
    Returns:
      A spliterator for an array
    Throws:
      `NullPointerException` - if the given array is `null`
      `ArrayIndexOutOfBoundsException` - if `fromIndex` is negative, `toIndex` is less than `fromIndex`, or `toIndex` is greater than the array size
    See Also:
      - `Arrays.spliterator(long[], int, int)`

  - ### spliterator

    public static Spliterator.OfDouble spliterator(double[] array, int additionalCharacteristics)
    Creates a `Spliterator.OfDouble` covering the elements of a given array, using a customized set of spliterator characteristics.

    This method is provided as an implementation convenience for Spliterators which store portions of their elements in arrays, and need fine control over Spliterator characteristics. Most other situations in which a Spliterator for an array is needed should use `Arrays.spliterator(double[])`.

    The returned spliterator always reports the characteristics `SIZED` and `SUBSIZED`. The caller may provide additional characteristics for the spliterator to report; it is common to additionally specify `IMMUTABLE` and `ORDERED`.

    Parameters:
      `array` - The array, assumed to be unmodified during use
      `additionalCharacteristics` - Additional spliterator characteristics of this spliterator's source or elements beyond `SIZED` and `SUBSIZED` which are always reported
    Returns:
      A spliterator for an array
    Throws:
      `NullPointerException` - if the given array is `null`
    See Also:
      - `Arrays.spliterator(double[])`

  - ### spliterator

    public static Spliterator.OfDouble spliterator(double[] array, int fromIndex, int toIndex, int additionalCharacteristics)
    Creates a `Spliterator.OfDouble` covering a range of elements of a given array, using a customized set of spliterator characteristics.

    This method is provided as an implementation convenience for Spliterators which store portions of their elements in arrays, and need fine control over Spliterator characteristics. Most other situations in which a Spliterator for an array is needed should use `Arrays.spliterator(double[], int, int)`.

    The returned spliterator always reports the characteristics `SIZED` and `SUBSIZED`. The caller may provide additional characteristics for the spliterator to report. (For example, if it is known the array will not be further modified, specify `IMMUTABLE`; if the array data is considered to have an encounter order, specify `ORDERED`). The method `Arrays.spliterator(long[], int, int)` can often be used instead, which returns a spliterator that reports `SIZED`, `SUBSIZED`, `IMMUTABLE`, and `ORDERED`.

    Parameters:
      `array` - The array, assumed to be unmodified during use
      `fromIndex` - The least index (inclusive) to cover
      `toIndex` - One past the greatest index to cover
      `additionalCharacteristics` - Additional spliterator characteristics of this spliterator's source or elements beyond `SIZED` and `SUBSIZED` which are always reported
    Returns:
      A spliterator for an array
    Throws:
      `NullPointerException` - if the given array is `null`
      `ArrayIndexOutOfBoundsException` - if `fromIndex` is negative, `toIndex` is less than `fromIndex`, or `toIndex` is greater than the array size
    See Also:
      - `Arrays.spliterator(double[], int, int)`

  - ### spliterator

    public static <T> Spliterator<T> spliterator(Collection<? extends T> c, int characteristics)
    Creates a `Spliterator` using the given collection's `iterator` as the source of elements, and reporting its `size` as its initial size.

    The spliterator is late-binding, inherits the fail-fast properties of the collection's iterator, and implements `trySplit` to permit limited parallelism.

    Type Parameters:
      `T` - Type of elements
    Parameters:
      `c` - The collection
      `characteristics` - Characteristics of this spliterator's source or elements. The characteristics `SIZED` and `SUBSIZED` are additionally reported unless `CONCURRENT` is supplied.
    Returns:
      A spliterator from an iterator
    Throws:
      `NullPointerException` - if the given collection is `null`

  - ### spliterator

    public static <T> Spliterator<T> spliterator(Iterator<? extends T> iterator, long size, int characteristics)
    Creates a `Spliterator` using a given `Iterator` as the source of elements, and with a given initially reported size.

    The spliterator is not late-binding, inherits the fail-fast properties of the iterator, and implements `trySplit` to permit limited parallelism.

    Traversal of elements should be accomplished through the spliterator. The behaviour of splitting and traversal is undefined if the iterator is operated on after the spliterator is returned, or the initially reported size is not equal to the actual number of elements in the source.

    Type Parameters:
      `T` - Type of elements
    Parameters:
      `iterator` - The iterator for the source
      `size` - The number of elements in the source, to be reported as initial `estimateSize`
      `characteristics` - Characteristics of this spliterator's source or elements. The characteristics `SIZED` and `SUBSIZED` are additionally reported unless `CONCURRENT` is supplied.
    Returns:
      A spliterator from an iterator
    Throws:
      `NullPointerException` - if the given iterator is `null`

  - ### spliteratorUnknownSize

    public static <T> Spliterator<T> spliteratorUnknownSize(Iterator<? extends T> iterator, int characteristics)
    Creates a `Spliterator` using a given `Iterator` as the source of elements, with no initial size estimate.

    The spliterator is not late-binding, inherits the fail-fast properties of the iterator, and implements `trySplit` to permit limited parallelism.

    Traversal of elements should be accomplished through the spliterator. The behaviour of splitting and traversal is undefined if the iterator is operated on after the spliterator is returned.

    Type Parameters:
      `T` - Type of elements
    Parameters:
      `iterator` - The iterator for the source
      `characteristics` - Characteristics of this spliterator's source or elements (`SIZED` and `SUBSIZED`, if supplied, are ignored and are not reported.)
    Returns:
      A spliterator from an iterator
    Throws:
      `NullPointerException` - if the given iterator is `null`

  - ### spliterator

    public static Spliterator.OfInt spliterator(PrimitiveIterator.OfInt iterator, long size, int characteristics)
    Creates a `Spliterator.OfInt` using a given `IntStream.IntIterator` as the source of elements, and with a given initially reported size.

    The spliterator is not late-binding, inherits the fail-fast properties of the iterator, and implements `trySplit` to permit limited parallelism.

    Traversal of elements should be accomplished through the spliterator. The behaviour of splitting and traversal is undefined if the iterator is operated on after the spliterator is returned, or the initially reported size is not equal to the actual number of elements in the source.

    Parameters:
      `iterator` - The iterator for the source
      `size` - The number of elements in the source, to be reported as initial `estimateSize`.
      `characteristics` - Characteristics of this spliterator's source or elements. The characteristics `SIZED` and `SUBSIZED` are additionally reported unless `CONCURRENT` is supplied.
    Returns:
      A spliterator from an iterator
    Throws:
      `NullPointerException` - if the given iterator is `null`

  - ### spliteratorUnknownSize

    public static Spliterator.OfInt spliteratorUnknownSize(PrimitiveIterator.OfInt iterator, int characteristics)
    Creates a `Spliterator.OfInt` using a given `IntStream.IntIterator` as the source of elements, with no initial size estimate.

    The spliterator is not late-binding, inherits the fail-fast properties of the iterator, and implements `trySplit` to permit limited parallelism.

    Traversal of elements should be accomplished through the spliterator. The behaviour of splitting and traversal is undefined if the iterator is operated on after the spliterator is returned.

    Parameters:
      `iterator` - The iterator for the source
      `characteristics` - Characteristics of this spliterator's source or elements (`SIZED` and `SUBSIZED`, if supplied, are ignored and are not reported.)
    Returns:
      A spliterator from an iterator
    Throws:
      `NullPointerException` - if the given iterator is `null`

  - ### spliterator

    public static Spliterator.OfLong spliterator(PrimitiveIterator.OfLong iterator, long size, int characteristics)
    Creates a `Spliterator.OfLong` using a given `LongStream.LongIterator` as the source of elements, and with a given initially reported size.

    The spliterator is not late-binding, inherits the fail-fast properties of the iterator, and implements `trySplit` to permit limited parallelism.

    Traversal of elements should be accomplished through the spliterator. The behaviour of splitting and traversal is undefined if the iterator is operated on after the spliterator is returned, or the initially reported size is not equal to the actual number of elements in the source.

    Parameters:
      `iterator` - The iterator for the source
      `size` - The number of elements in the source, to be reported as initial `estimateSize`.
      `characteristics` - Characteristics of this spliterator's source or elements. The characteristics `SIZED` and `SUBSIZED` are additionally reported unless `CONCURRENT` is supplied.
    Returns:
      A spliterator from an iterator
    Throws:
      `NullPointerException` - if the given iterator is `null`

  - ### spliteratorUnknownSize

    public static Spliterator.OfLong spliteratorUnknownSize(PrimitiveIterator.OfLong iterator, int characteristics)
    Creates a `Spliterator.OfLong` using a given `LongStream.LongIterator` as the source of elements, with no initial size estimate.

    The spliterator is not late-binding, inherits the fail-fast properties of the iterator, and implements `trySplit` to permit limited parallelism.

    Traversal of elements should be accomplished through the spliterator. The behaviour of splitting and traversal is undefined if the iterator is operated on after the spliterator is returned.

    Parameters:
      `iterator` - The iterator for the source
      `characteristics` - Characteristics of this spliterator's source or elements (`SIZED` and `SUBSIZED`, if supplied, are ignored and are not reported.)
    Returns:
      A spliterator from an iterator
    Throws:
      `NullPointerException` - if the given iterator is `null`

  - ### spliterator

    public static Spliterator.OfDouble spliterator(PrimitiveIterator.OfDouble iterator, long size, int characteristics)
    Creates a `Spliterator.OfDouble` using a given `DoubleStream.DoubleIterator` as the source of elements, and with a given initially reported size.

    The spliterator is not late-binding, inherits the fail-fast properties of the iterator, and implements `trySplit` to permit limited parallelism.

    Traversal of elements should be accomplished through the spliterator. The behaviour of splitting and traversal is undefined if the iterator is operated on after the spliterator is returned, or the initially reported size is not equal to the actual number of elements in the source.

    Parameters:
      `iterator` - The iterator for the source
      `size` - The number of elements in the source, to be reported as initial `estimateSize`
      `characteristics` - Characteristics of this spliterator's source or elements. The characteristics `SIZED` and `SUBSIZED` are additionally reported unless `CONCURRENT` is supplied.
    Returns:
      A spliterator from an iterator
    Throws:
      `NullPointerException` - if the given iterator is `null`

  - ### spliteratorUnknownSize

    public static Spliterator.OfDouble spliteratorUnknownSize(PrimitiveIterator.OfDouble iterator, int characteristics)
    Creates a `Spliterator.OfDouble` using a given `DoubleStream.DoubleIterator` as the source of elements, with no initial size estimate.

    The spliterator is not late-binding, inherits the fail-fast properties of the iterator, and implements `trySplit` to permit limited parallelism.

    Traversal of elements should be accomplished through the spliterator. The behaviour of splitting and traversal is undefined if the iterator is operated on after the spliterator is returned.

    Parameters:
      `iterator` - The iterator for the source
      `characteristics` - Characteristics of this spliterator's source or elements (`SIZED` and `SUBSIZED`, if supplied, are ignored and are not reported.)
    Returns:
      A spliterator from an iterator
    Throws:
      `NullPointerException` - if the given iterator is `null`

  - ### iterator

    public static <T> Iterator<T> iterator(Spliterator<? extends T> spliterator)
    Creates an `Iterator` from a `Spliterator`.

    Traversal of elements should be accomplished through the iterator. The behaviour of traversal is undefined if the spliterator is operated after the iterator is returned.

    Type Parameters:
      `T` - Type of elements
    Parameters:
      `spliterator` - The spliterator
    Returns:
      An iterator
    Throws:
      `NullPointerException` - if the given spliterator is `null`

  - ### iterator

    public static PrimitiveIterator.OfInt iterator(Spliterator.OfInt spliterator)
    Creates an `PrimitiveIterator.OfInt` from a `Spliterator.OfInt`.

    Traversal of elements should be accomplished through the iterator. The behaviour of traversal is undefined if the spliterator is operated after the iterator is returned.

    Parameters:
      `spliterator` - The spliterator
    Returns:
      An iterator
    Throws:
      `NullPointerException` - if the given spliterator is `null`

  - ### iterator

    public static PrimitiveIterator.OfLong iterator(Spliterator.OfLong spliterator)
    Creates an `PrimitiveIterator.OfLong` from a `Spliterator.OfLong`.

    Traversal of elements should be accomplished through the iterator. The behaviour of traversal is undefined if the spliterator is operated after the iterator is returned.

    Parameters:
      `spliterator` - The spliterator
    Returns:
      An iterator
    Throws:
      `NullPointerException` - if the given spliterator is `null`

  - ### iterator

    public static PrimitiveIterator.OfDouble iterator(Spliterator.OfDouble spliterator)
    Creates an `PrimitiveIterator.OfDouble` from a `Spliterator.OfDouble`.

    Traversal of elements should be accomplished through the iterator. The behaviour of traversal is undefined if the spliterator is operated after the iterator is returned.

    Parameters:
      `spliterator` - The spliterator
    Returns:
      An iterator
    Throws:
      `NullPointerException` - if the given spliterator is `null`