StreamSupport

AI-generated Key Takeaways

• StreamSupport provides low-level methods for creating and manipulating streams from Spliterators.

• It is primarily intended for library authors to create stream views of data structures.

• StreamSupport offers methods to create sequential or parallel streams of different types (IntStream, LongStream, DoubleStream, and Stream).

• It allows creating streams directly from a Spliterator or using a Supplier for deferred execution and reduced interference with the source.

• For most end-users, the static stream methods in the Stream classes are sufficient.

public final class StreamSupport extends Object

Low-level utility methods for creating and manipulating streams.

This class is mostly for library writers presenting stream views of data structures; most static stream methods intended for end users are in the various Stream classes.

Public Method Summary

static DoubleStream	doubleStream(Spliterator.OfDouble spliterator, boolean parallel) Creates a new sequential or parallel DoubleStream from a Spliterator.OfDouble.
static DoubleStream	doubleStream(Supplier<? extends Spliterator.OfDouble> supplier, int characteristics, boolean parallel) Creates a new sequential or parallel DoubleStream from a Supplier of Spliterator.OfDouble.
static IntStream	intStream(Spliterator.OfInt spliterator, boolean parallel) Creates a new sequential or parallel IntStream from a Spliterator.OfInt.
static IntStream	intStream(Supplier<? extends Spliterator.OfInt> supplier, int characteristics, boolean parallel) Creates a new sequential or parallel IntStream from a Supplier of Spliterator.OfInt.
static LongStream	longStream(Spliterator.OfLong spliterator, boolean parallel) Creates a new sequential or parallel LongStream from a Spliterator.OfLong.
static LongStream	longStream(Supplier<? extends Spliterator.OfLong> supplier, int characteristics, boolean parallel) Creates a new sequential or parallel LongStream from a Supplier of Spliterator.OfLong.
static <T> Stream<T>	stream(Spliterator<T> spliterator, boolean parallel) Creates a new sequential or parallel Stream from a Spliterator.
static <T> Stream<T>	stream(Supplier<? extends Spliterator<T>> supplier, int characteristics, boolean parallel) Creates a new sequential or parallel Stream from a Supplier of Spliterator.

Inherited Method Summary

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

Public Methods

public static DoubleStream doubleStream (Spliterator.OfDouble spliterator, boolean parallel)

Creates a new sequential or parallel DoubleStream from a Spliterator.OfDouble.

The spliterator is only traversed, split, or queried for estimated size after the terminal operation of the stream pipeline commences.

It is strongly recommended the spliterator report a characteristic of IMMUTABLE or CONCURRENT, or be late-binding. Otherwise, doubleStream(java.util.function.Supplier, int, boolean) should be used to reduce the scope of potential interference with the source. See Non-Interference for more details.

Parameters

spliterator	A Spliterator.OfDouble describing the stream elements
parallel	if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.

Returns

• a new sequential or parallel DoubleStream

public static DoubleStream doubleStream (Supplier<? extends Spliterator.OfDouble> supplier, int characteristics, boolean parallel)

Creates a new sequential or parallel DoubleStream from a Supplier of Spliterator.OfDouble.

The Supplier.get() method will be invoked on the supplier no more than once, and only after the terminal operation of the stream pipeline commences.

For spliterators that report a characteristic of IMMUTABLE or CONCURRENT, or that are late-binding, it is likely more efficient to use doubleStream(java.util.Spliterator.OfDouble, boolean) instead.

The use of a Supplier in this form provides a level of indirection that reduces the scope of potential interference with the source. Since the supplier is only invoked after the terminal operation commences, any modifications to the source up to the start of the terminal operation are reflected in the stream result. See Non-Interference for more details.

Parameters

supplier	A Supplier of a Spliterator.OfDouble
characteristics	Spliterator characteristics of the supplied Spliterator.OfDouble. The characteristics must be equal to supplier.get().characteristics(), otherwise undefined behavior may occur when terminal operation commences.
parallel	if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.

Returns

• a new sequential or parallel DoubleStream

See Also

• doubleStream(java.util.Spliterator.OfDouble, boolean)

public static IntStream intStream (Spliterator.OfInt spliterator, boolean parallel)

Creates a new sequential or parallel IntStream from a Spliterator.OfInt.

The spliterator is only traversed, split, or queried for estimated size after the terminal operation of the stream pipeline commences.

It is strongly recommended the spliterator report a characteristic of IMMUTABLE or CONCURRENT, or be late-binding. Otherwise, intStream(java.util.function.Supplier, int, boolean) should be used to reduce the scope of potential interference with the source. See Non-Interference for more details.

Parameters

spliterator	a Spliterator.OfInt describing the stream elements
parallel	if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.

Returns

• a new sequential or parallel IntStream

public static IntStream intStream (Supplier<? extends Spliterator.OfInt> supplier, int characteristics, boolean parallel)

Creates a new sequential or parallel IntStream from a Supplier of Spliterator.OfInt.

The Supplier.get() method will be invoked on the supplier no more than once, and only after the terminal operation of the stream pipeline commences.

For spliterators that report a characteristic of IMMUTABLE or CONCURRENT, or that are late-binding, it is likely more efficient to use intStream(java.util.Spliterator.OfInt, boolean) instead.

The use of a Supplier in this form provides a level of indirection that reduces the scope of potential interference with the source. Since the supplier is only invoked after the terminal operation commences, any modifications to the source up to the start of the terminal operation are reflected in the stream result. See Non-Interference for more details.

Parameters

supplier	a Supplier of a Spliterator.OfInt
characteristics	Spliterator characteristics of the supplied Spliterator.OfInt. The characteristics must be equal to supplier.get().characteristics(), otherwise undefined behavior may occur when terminal operation commences.
parallel	if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.

Returns

• a new sequential or parallel IntStream

See Also

• intStream(java.util.Spliterator.OfInt, boolean)

public static LongStream longStream (Spliterator.OfLong spliterator, boolean parallel)

Creates a new sequential or parallel LongStream from a Spliterator.OfLong.

The spliterator is only traversed, split, or queried for estimated size after the terminal operation of the stream pipeline commences.

It is strongly recommended the spliterator report a characteristic of IMMUTABLE or CONCURRENT, or be late-binding. Otherwise, longStream(java.util.function.Supplier, int, boolean) should be used to reduce the scope of potential interference with the source. See Non-Interference for more details.

Parameters

spliterator	a Spliterator.OfLong describing the stream elements
parallel	if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.

Returns

• a new sequential or parallel LongStream

public static LongStream longStream (Supplier<? extends Spliterator.OfLong> supplier, int characteristics, boolean parallel)

Creates a new sequential or parallel LongStream from a Supplier of Spliterator.OfLong.

The Supplier.get() method will be invoked on the supplier no more than once, and only after the terminal operation of the stream pipeline commences.

For spliterators that report a characteristic of IMMUTABLE or CONCURRENT, or that are late-binding, it is likely more efficient to use longStream(java.util.Spliterator.OfLong, boolean) instead.

The use of a Supplier in this form provides a level of indirection that reduces the scope of potential interference with the source. Since the supplier is only invoked after the terminal operation commences, any modifications to the source up to the start of the terminal operation are reflected in the stream result. See Non-Interference for more details.

Parameters

supplier	a Supplier of a Spliterator.OfLong
characteristics	Spliterator characteristics of the supplied Spliterator.OfLong. The characteristics must be equal to supplier.get().characteristics(), otherwise undefined behavior may occur when terminal operation commences.
parallel	if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.

Returns

• a new sequential or parallel LongStream

See Also

• longStream(java.util.Spliterator.OfLong, boolean)

public static Stream<T> stream (Spliterator<T> spliterator, boolean parallel)

Creates a new sequential or parallel Stream from a Spliterator.

The spliterator is only traversed, split, or queried for estimated size after the terminal operation of the stream pipeline commences.

It is strongly recommended the spliterator report a characteristic of IMMUTABLE or CONCURRENT, or be late-binding. Otherwise, stream(java.util.function.Supplier, int, boolean) should be used to reduce the scope of potential interference with the source. See Non-Interference for more details.

Parameters

spliterator	a Spliterator describing the stream elements
parallel	if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.

Returns

• a new sequential or parallel Stream

public static Stream<T> stream (Supplier<? extends Spliterator<T>> supplier, int characteristics, boolean parallel)

Creates a new sequential or parallel Stream from a Supplier of Spliterator.

The Supplier.get() method will be invoked on the supplier no more than once, and only after the terminal operation of the stream pipeline commences.

For spliterators that report a characteristic of IMMUTABLE or CONCURRENT, or that are late-binding, it is likely more efficient to use stream(java.util.Spliterator, boolean) instead.

The use of a Supplier in this form provides a level of indirection that reduces the scope of potential interference with the source. Since the supplier is only invoked after the terminal operation commences, any modifications to the source up to the start of the terminal operation are reflected in the stream result. See Non-Interference for more details.

Parameters

supplier	a Supplier of a Spliterator
characteristics	Spliterator characteristics of the supplied Spliterator. The characteristics must be equal to supplier.get().characteristics(), otherwise undefined behavior may occur when terminal operation commences.
parallel	if true then the returned stream is a parallel stream; if false the returned stream is a sequential stream.

Returns

• a new sequential or parallel Stream

See Also

• stream(java.util.Spliterator, boolean)