Package com.infilos.utils.stream

Class ParallelDoubleStream

java.lang.Object

com.infilos.utils.stream.ParallelDoubleStream

All Implemented Interfaces:

AutoCloseable, BaseStream<Double,DoubleStream>, DoubleStream

public class ParallelDoubleStream
extends Object
implements DoubleStream

An implementation of DoubleStream which uses a custom ForkJoinPool for parallel aggregate operations. This is the double primitive specialization of ParallelStream.

The following example illustrates an aggregate operation using ParallelStream and ParallelDoubleStream with a custom ForkJoinPool, computing the sum of the weights of the red widgets:

 ForkJoinPool pool = new ForkJoinPool();
 double sum = ParallelStreamSupport.parallelStream(widgets, pool)
     .filter(w -> w.getColor() == RED)
     .mapToDouble(w -> w.getWeight())
     .sum();
 

In case this stream is configured for parallel execution, i.e. BaseStream.isParallel() returns true, a terminal operation will be executed as ForkJoinTask in the custom ForkJoinPool. Otherwise it will be executed in the calling thread.

This implementation offers various factory methods which are based on:

• The static factory methods of DoubleStream, which are meaningful for parallel streams
• Arrays.stream(double[])
• StreamSupport.doubleStream(Spliterator.OfDouble, boolean)
• StreamSupport.doubleStream(Supplier, int, boolean)

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.stream.DoubleStream

DoubleStream.Builder

Method Summary

Modifier and Type	Method	Description
boolean	allMatch(DoublePredicate predicate)
boolean	anyMatch(DoublePredicate predicate)
OptionalDouble	average()
Stream<Double>	boxed()
void	close()
<R> R	collect(Supplier<R> supplier, ObjDoubleConsumer<R> accumulator, BiConsumer<R,R> combiner)
static DoubleStream	concat(DoubleStream a, DoubleStream b, ForkJoinPool workerPool)	Creates a lazily concatenated parallel double stream whose elements are all the elements of the first stream followed by all the elements of the second stream.
long	count()
DoubleStream	distinct()
protected void	execute(Runnable terminalOperation)
protected <R> R	execute(Callable<R> terminalOperation)
DoubleStream	filter(DoublePredicate predicate)
OptionalDouble	findAny()
OptionalDouble	findFirst()
DoubleStream	flatMap(DoubleFunction<? extends DoubleStream> mapper)
void	forEach(DoubleConsumer action)
void	forEachOrdered(DoubleConsumer action)
static DoubleStream	generate(DoubleSupplier supplier, ForkJoinPool workerPool)	Creates a parallel infinite sequential unordered double stream where each element is generated by the provided DoubleSupplier.
boolean	isParallel()
static DoubleStream	iterate(double seed, DoubleUnaryOperator operator, ForkJoinPool workerPool)	Creates a parallel infinite ordered double stream produced by iterative application of a function f to an initial element seed.
PrimitiveIterator.OfDouble	iterator()
DoubleStream	limit(long maxSize)
DoubleStream	map(DoubleUnaryOperator mapper)
IntStream	mapToInt(DoubleToIntFunction mapper)
LongStream	mapToLong(DoubleToLongFunction mapper)
<U> Stream<U>	mapToObj(DoubleFunction<? extends U> mapper)
OptionalDouble	max()
OptionalDouble	min()
boolean	noneMatch(DoublePredicate predicate)
S	onClose(Runnable closeHandler)
S	parallel()
DoubleStream	peek(DoubleConsumer action)
double	reduce(double identity, DoubleBinaryOperator op)
OptionalDouble	reduce(DoubleBinaryOperator op)
S	sequential()
DoubleStream	skip(long n)
DoubleStream	sorted()
Spliterator.OfDouble	spliterator()
static DoubleStream	submit(double[] array, ForkJoinPool workerPool)	Creates a parallel double stream from the given Array.
static DoubleStream	submit(Supplier<? extends Spliterator.OfDouble> supplier, int characteristics, ForkJoinPool workerPool)	Creates a parallel double stream from the given Spliterator supplier.
static DoubleStream	submit(Spliterator.OfDouble spliterator, ForkJoinPool workerPool)	Creates a parallel double stream from the given Spliterator.
static DoubleStream	submit(DoubleStream.Builder builder, ForkJoinPool workerPool)	Creates a parallel double stream from the given DoubleStream.Builder.
double	sum()
DoubleSummaryStatistics	summaryStatistics()
double[]	toArray()
S	unordered()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.stream.BaseStream

close, isParallel, onClose, unordered

Methods inherited from interface java.util.stream.DoubleStream

dropWhile, parallel, sequential, takeWhile

Method Detail

submit

public static DoubleStream submit(double[] array,
                                  ForkJoinPool workerPool)

Creates a parallel double stream from the given Array. This operation is similar to calling Arrays.stream(array).parallel() with the difference that a parallel terminal operation will be executed in the given ForkJoinPool.

Parameters:

array - Array to create the parallel stream from. Must not be null.

workerPool - Thread pool for parallel execution of a terminal operation. Must not be null.

Returns:

A parallel double stream that executes a terminal operation in the given ForkJoinPool.

See Also:

Arrays.stream(int[])

submit

public static DoubleStream submit(Spliterator.OfDouble spliterator,
                                  ForkJoinPool workerPool)

Creates a parallel double stream from the given Spliterator. This operation is similar to calling StreamSupport.doubleStream(spliterator, true) with the difference that a parallel terminal operation will be executed in the given ForkJoinPool.

Parameters:

spliterator - A Spliterator.OfDouble describing the stream elements. Must not be null.

workerPool - Thread pool for parallel execution of a terminal operation. Must not be null.

Returns:

A parallel double stream that executes a terminal operation in the given ForkJoinPool.

See Also:

StreamSupport.doubleStream(Spliterator.OfDouble, boolean)

submit

public static DoubleStream submit(Supplier<? extends Spliterator.OfDouble> supplier,
                                  int characteristics,
                                  ForkJoinPool workerPool)

Creates a parallel double stream from the given Spliterator supplier. This operation is similar to calling StreamSupport.doubleStream(supplier, characteristics, true) with the difference that a parallel terminal operation will be executed in the given ForkJoinPool.

Parameters:

supplier - A Supplier of a Spliterator.OfDouble. Must not be null.

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.

workerPool - Thread pool for parallel execution of a terminal operation. Must not be null.

Returns:

A parallel double stream that executes a terminal operation in the given ForkJoinPool.

See Also:

StreamSupport.doubleStream(Supplier, int, boolean)

submit

public static DoubleStream submit(DoubleStream.Builder builder,
                                  ForkJoinPool workerPool)

Creates a parallel double stream from the given DoubleStream.Builder. This operation is similar to calling builder.build().parallel() with the difference that a parallel terminal operation will be executed in the given ForkJoinPool.

Parameters:

builder - The builder to create the stream from. Must not be null.

workerPool - Thread pool for parallel execution of a terminal operation. Must not be null.

Returns:

A parallel double stream that executes a terminal operation in the given ForkJoinPool.

See Also:

DoubleStream.builder()

iterate

public static DoubleStream iterate(double seed,
                                   DoubleUnaryOperator operator,
                                   ForkJoinPool workerPool)

Creates a parallel infinite ordered double stream produced by iterative application of a function f to an initial element seed. This operation is similar to calling DoubleStream.iterate(seed, operator).parallel() with the difference that a parallel terminal operation will be executed in the given ForkJoinPool.

Parameters:

seed - The initial element.

operator - A function to be applied to to the previous element to produce a new element. Must not be null.

workerPool - Thread pool for parallel execution of a terminal operation. Must not be null.

Returns:

A parallel double stream that executes a terminal operation in the given ForkJoinPool.

See Also:

DoubleStream.iterate(double, DoubleUnaryOperator)

generate

public static DoubleStream generate(DoubleSupplier supplier,
                                    ForkJoinPool workerPool)

Creates a parallel infinite sequential unordered double stream where each element is generated by the provided DoubleSupplier. This operation is similar to calling DoubleStream.generate(supplier).parallel() with the difference that a parallel terminal operation will be executed in the given ForkJoinPool.

Parameters:

supplier - The DoubleSupplier of generated elements. Must not be null.

workerPool - Thread pool for parallel execution of a terminal operation. Must not be null.

Returns:

A parallel double stream that executes a terminal operation in the given ForkJoinPool.

See Also:

DoubleStream.generate(DoubleSupplier)

concat

public static DoubleStream concat(DoubleStream a,
                                  DoubleStream b,
                                  ForkJoinPool workerPool)

Creates a lazily concatenated parallel double stream whose elements are all the elements of the first stream followed by all the elements of the second stream. This operation is similar to calling DoubleStream.concat(a, b).parallel() with the difference that a parallel terminal operation will be executed in the given ForkJoinPool.

Parameters:

a - The first stream. Must not be null.

b - The second stream. Must not be null.

workerPool - Thread pool for parallel execution of a terminal operation. Must not be null.

Returns:

A parallel stream that executes a terminal operation in the given ForkJoinPool.

See Also:

DoubleStream.concat(DoubleStream, DoubleStream)

filter

public DoubleStream filter(DoublePredicate predicate)

Specified by:

filter in interface DoubleStream

map

public DoubleStream map(DoubleUnaryOperator mapper)

Specified by:

map in interface DoubleStream

mapToObj

public <U> Stream<U> mapToObj(DoubleFunction<? extends U> mapper)

Specified by:

mapToObj in interface DoubleStream

mapToInt

public IntStream mapToInt(DoubleToIntFunction mapper)

Specified by:

mapToInt in interface DoubleStream

mapToLong

public LongStream mapToLong(DoubleToLongFunction mapper)

Specified by:

mapToLong in interface DoubleStream

flatMap

public DoubleStream flatMap(DoubleFunction<? extends DoubleStream> mapper)

Specified by:

flatMap in interface DoubleStream

distinct

public DoubleStream distinct()

Specified by:

distinct in interface DoubleStream

sorted

public DoubleStream sorted()

Specified by:

sorted in interface DoubleStream

peek

public DoubleStream peek(DoubleConsumer action)

Specified by:

peek in interface DoubleStream

limit

public DoubleStream limit(long maxSize)

Specified by:

limit in interface DoubleStream

skip

public DoubleStream skip(long n)

Specified by:

skip in interface DoubleStream

forEach

public void forEach(DoubleConsumer action)

Specified by:

forEach in interface DoubleStream

forEachOrdered

public void forEachOrdered(DoubleConsumer action)

Specified by:

forEachOrdered in interface DoubleStream

toArray

public double[] toArray()

Specified by:

toArray in interface DoubleStream

reduce

public double reduce(double identity,
                     DoubleBinaryOperator op)

Specified by:

reduce in interface DoubleStream

reduce

public OptionalDouble reduce(DoubleBinaryOperator op)

Specified by:

reduce in interface DoubleStream

collect

public <R> R collect(Supplier<R> supplier,
                     ObjDoubleConsumer<R> accumulator,
                     BiConsumer<R,R> combiner)

Specified by:

collect in interface DoubleStream

sum

public double sum()

Specified by:

sum in interface DoubleStream

min

public OptionalDouble min()

Specified by:

min in interface DoubleStream

max

public OptionalDouble max()

Specified by:

max in interface DoubleStream

count

public long count()

Specified by:

count in interface DoubleStream

average

public OptionalDouble average()

Specified by:

average in interface DoubleStream

summaryStatistics

public DoubleSummaryStatistics summaryStatistics()

Specified by:

summaryStatistics in interface DoubleStream

anyMatch

public boolean anyMatch(DoublePredicate predicate)

Specified by:

anyMatch in interface DoubleStream

allMatch

public boolean allMatch(DoublePredicate predicate)

Specified by:

allMatch in interface DoubleStream

noneMatch

public boolean noneMatch(DoublePredicate predicate)

Specified by:

noneMatch in interface DoubleStream

findFirst

public OptionalDouble findFirst()

Specified by:

findFirst in interface DoubleStream

findAny

public OptionalDouble findAny()

Specified by:

findAny in interface DoubleStream

boxed

public Stream<Double> boxed()

Specified by:

boxed in interface DoubleStream

iterator

public PrimitiveIterator.OfDouble iterator()

Specified by:

iterator in interface BaseStream<Double,DoubleStream>

Specified by:

iterator in interface DoubleStream

spliterator

public Spliterator.OfDouble spliterator()

Specified by:

spliterator in interface BaseStream<Double,DoubleStream>

Specified by:

spliterator in interface DoubleStream

isParallel

public boolean isParallel()

Specified by:

isParallel in interface BaseStream<T,S extends BaseStream<T,S>>

sequential

public S sequential()

Specified by:

sequential in interface BaseStream<T,S extends BaseStream<T,S>>

parallel

public S parallel()

Specified by:

parallel in interface BaseStream<T,S extends BaseStream<T,S>>

unordered

public S unordered()

Specified by:

unordered in interface BaseStream<T,S extends BaseStream<T,S>>

onClose

public S onClose(Runnable closeHandler)

Specified by:

onClose in interface BaseStream<T,S extends BaseStream<T,S>>

close

public void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface BaseStream<T,S extends BaseStream<T,S>>

execute

protected void execute(Runnable terminalOperation)

execute

protected <R> R execute(Callable<R> terminalOperation)