com.hazelcast.jet.stream

Interface DistributedStream<T>

Type Parameters:

T - the type of the stream elements

All Superinterfaces:

AutoCloseable, java.util.stream.BaseStream<T,java.util.stream.Stream<T>>, java.util.stream.Stream<T>

public interface DistributedStream<T>
extends java.util.stream.Stream<T>

An extension of Stream that supports distributed stream operations by replacing functional interfaces with their serializable equivalents.

Nested Class Summary

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

java.util.stream.Stream.Builder<T>

Method Summary

Modifier and Type	Method and Description
default boolean	allMatch(DistributedPredicate<? super T> predicate) Returns whether all elements of this stream match the provided predicate.
boolean	allMatch(java.util.function.Predicate<? super T> predicate)
default boolean	anyMatch(DistributedPredicate<? super T> predicate) Returns whether any elements of this stream match the provided predicate.
boolean	anyMatch(java.util.function.Predicate<? super T> predicate)
<R> R	collect(DistributedCollector.Reducer<? super T,R> reducer) Terminate the stream using a reduction performed by DistributedCollector.Reducer and return the resulting value.
default <R,A> R	collect(DistributedCollector<? super T,A,R> collector) Performs a mutable reduction operation on the elements of this stream using a DistributedCollector.
default <R> R	collect(DistributedSupplier<R> supplier, DistributedBiConsumer<R,? super T> accumulator, DistributedBiConsumer<R,R> combiner) Performs a mutable reduction operation on the elements of this stream.
<R> R	collect(java.util.function.Supplier<R> supplier, java.util.function.BiConsumer<R,? super T> accumulator, java.util.function.BiConsumer<R,R> combiner)
DistributedStream<T>	configure(JobConfig jobConfig)
DistributedStream<T>	distinct()
default DistributedStream<T>	filter(DistributedPredicate<? super T> predicate) Returns a stream consisting of the elements of this stream that match the given predicate.
DistributedStream<T>	filter(java.util.function.Predicate<? super T> predicate)
default <R> DistributedStream<R>	flatMap(DistributedFunction<? super T,? extends java.util.stream.Stream<? extends R>> mapper) Returns a stream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element.
<R> DistributedStream<R>	flatMap(java.util.function.Function<? super T,? extends java.util.stream.Stream<? extends R>> mapper)
default DistributedDoubleStream	flatMapToDouble(DistributedFunction<? super T,? extends java.util.stream.DoubleStream> mapper) Returns an DoubleStream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element.
DistributedDoubleStream	flatMapToDouble(java.util.function.Function<? super T,? extends java.util.stream.DoubleStream> mapper)
default DistributedIntStream	flatMapToInt(DistributedFunction<? super T,? extends java.util.stream.IntStream> mapper) Returns an IntStream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element.
DistributedIntStream	flatMapToInt(java.util.function.Function<? super T,? extends java.util.stream.IntStream> mapper)
default DistributedLongStream	flatMapToLong(DistributedFunction<? super T,? extends java.util.stream.LongStream> mapper) Returns an LongStream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element.
DistributedLongStream	flatMapToLong(java.util.function.Function<? super T,? extends java.util.stream.LongStream> mapper)
static <T> DistributedStream<T>	fromSource(JetInstance instance, ProcessorMetaSupplier metaSupplier) Returns a distributed Stream with given processors as its source.
DistributedStream<T>	limit(long maxSize)
default <R> DistributedStream<R>	map(DistributedFunction<? super T,? extends R> mapper) Returns a stream consisting of the results of applying the given function to the elements of this stream.
<R> DistributedStream<R>	map(java.util.function.Function<? super T,? extends R> mapper)
default DistributedDoubleStream	mapToDouble(DistributedToDoubleFunction<? super T> mapper) Returns a DistributedDoubleStream consisting of the results of applying the given function to the elements of this stream.
DistributedDoubleStream	mapToDouble(java.util.function.ToDoubleFunction<? super T> mapper)
default DistributedIntStream	mapToInt(DistributedToIntFunction<? super T> mapper) Returns an DistributedIntStream consisting of the results of applying the given function to the elements of this stream.
DistributedIntStream	mapToInt(java.util.function.ToIntFunction<? super T> mapper)
default DistributedLongStream	mapToLong(DistributedToLongFunction<? super T> mapper) Returns a DistributedLongStream consisting of the results of applying the given function to the elements of this stream.
DistributedLongStream	mapToLong(java.util.function.ToLongFunction<? super T> mapper)
Optional<T>	max(Comparator<? super T> comparator)
default Optional<T>	max(DistributedComparator<? super T> comparator) Returns the maximum element of this stream according to the provided DistributedComparator.
Optional<T>	min(Comparator<? super T> comparator)
default Optional<T>	min(DistributedComparator<? super T> comparator) Returns the minimum element of this stream according to the provided DistributedComparator.
default boolean	noneMatch(DistributedPredicate<? super T> predicate) Returns whether no elements of this stream match the provided predicate.
boolean	noneMatch(java.util.function.Predicate<? super T> predicate)
DistributedStream<T>	parallel()
DistributedStream<T>	peek(java.util.function.Consumer<? super T> action)
default DistributedStream<T>	peek(DistributedConsumer<? super T> action) Returns a stream consisting of the elements of this stream, additionally performing the provided action on each element as elements are consumed from the resulting stream.
Optional<T>	reduce(java.util.function.BinaryOperator<T> accumulator)
default Optional<T>	reduce(DistributedBinaryOperator<T> accumulator) Performs a reduction on the elements of this stream, using an associative accumulation function, and returns an Optional describing the reduced value, if any.
T	reduce(T identity, java.util.function.BinaryOperator<T> accumulator)
default T	reduce(T identity, DistributedBinaryOperator<T> accumulator) Performs a reduction on the elements of this stream, using the provided identity value and an associative accumulation function, and returns the reduced value.
<U> U	reduce(U identity, java.util.function.BiFunction<U,? super T,U> accumulator, java.util.function.BinaryOperator<U> combiner)
default <U> U	reduce(U identity, DistributedBiFunction<U,? super T,U> accumulator, DistributedBinaryOperator<U> combiner) Performs a reduction on the elements of this stream, using the provided identity, accumulation and combining functions.
DistributedStream<T>	sequential()
DistributedStream<T>	skip(long n)
DistributedStream<T>	sorted()
DistributedStream<T>	sorted(Comparator<? super T> comparator)
default DistributedStream<T>	sorted(DistributedComparator<? super T> comparator) Returns a stream consisting of the elements of this stream, sorted according to the provided Comparator.
DistributedStream<T>	unordered()

Methods inherited from interface java.util.stream.Stream

builder, collect, concat, count, empty, findAny, findFirst, forEach, forEachOrdered, generate, iterate, of, of, toArray, toArray

Methods inherited from interface java.util.stream.BaseStream

close, isParallel, iterator, onClose, spliterator

Method Detail

fromSource

static <T> DistributedStream<T> fromSource(JetInstance instance,
                                           ProcessorMetaSupplier metaSupplier)

Returns a distributed Stream with given processors as its source.

filter

default DistributedStream<T> filter(DistributedPredicate<? super T> predicate)

Returns a stream consisting of the elements of this stream that match the given predicate.

This is an intermediate operation.

Parameters:

predicate - a non-interfering, stateless predicate to apply to each element to determine if it should be included

Returns:

the new stream

map

default <R> DistributedStream<R> map(DistributedFunction<? super T,? extends R> mapper)

Returns a stream consisting of the results of applying the given function to the elements of this stream.

This is an intermediate operation.

Type Parameters:

R - The element type of the new stream

Parameters:

mapper - a non-interfering, stateless function to apply to each element

Returns:

the new stream

mapToInt

default DistributedIntStream mapToInt(DistributedToIntFunction<? super T> mapper)

Returns an DistributedIntStream consisting of the results of applying the given function to the elements of this stream.

This is an intermediate operation.

Parameters:

mapper - a non-interfering, stateless function to apply to each element

Returns:

the new stream

mapToLong

default DistributedLongStream mapToLong(DistributedToLongFunction<? super T> mapper)

Returns a DistributedLongStream consisting of the results of applying the given function to the elements of this stream.

This is an intermediate operation.

Parameters:

mapper - a non-interfering, stateless function to apply to each element

Returns:

the new stream

mapToDouble

default DistributedDoubleStream mapToDouble(DistributedToDoubleFunction<? super T> mapper)

Returns a DistributedDoubleStream consisting of the results of applying the given function to the elements of this stream.

This is an intermediate operation.

Parameters:

mapper - a non-interfering, stateless function to apply to each element

Returns:

the new stream

flatMap

default <R> DistributedStream<R> flatMap(DistributedFunction<? super T,? extends java.util.stream.Stream<? extends R>> mapper)

Returns a stream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element. Each mapped stream is closed after its contents have been placed into this stream. (If a mapped stream is null an empty stream is used, instead.)

This is an intermediate operation.

Type Parameters:

R - The element type of the new stream

Parameters:

mapper - a non-interfering, stateles function to apply to each element which produces a stream of new values

Returns:

the new stream

flatMapToInt

default DistributedIntStream flatMapToInt(DistributedFunction<? super T,? extends java.util.stream.IntStream> mapper)

Returns an IntStream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element. Each mapped stream is closed after its contents have been placed into this stream. (If a mapped stream is null an empty stream is used, instead.)

This is an intermediate operation.

Parameters:

mapper - a non-interfering, stateless function to apply to each element which produces a stream of new values

Returns:

the new stream

See Also:

flatMap(Function)

flatMapToLong

default DistributedLongStream flatMapToLong(DistributedFunction<? super T,? extends java.util.stream.LongStream> mapper)

Returns an LongStream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element. Each mapped stream is closed after its contents have been placed into this stream. (If a mapped stream is null an empty stream is used, instead.)

This is an intermediate operation.

Parameters:

mapper - a non-interfering, stateless function to apply to each element which produces a stream of new values

Returns:

the new stream

See Also:

flatMap(Function)

flatMapToDouble

default DistributedDoubleStream flatMapToDouble(DistributedFunction<? super T,? extends java.util.stream.DoubleStream> mapper)

Returns an DoubleStream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element. Each mapped stream is closed after its contents have placed been into this stream. (If a mapped stream is null an empty stream is used, instead.)

This is an intermediate operation.

Parameters:

mapper - a non-interfering, stateless function to apply to each element which produces a stream of new values

Returns:

the new stream

See Also:

flatMap(Function)

distinct

DistributedStream<T> distinct()

Specified by:

distinct in interface java.util.stream.Stream<T>

sorted

DistributedStream<T> sorted()

Specified by:

sorted in interface java.util.stream.Stream<T>

sorted

default DistributedStream<T> sorted(DistributedComparator<? super T> comparator)

Returns a stream consisting of the elements of this stream, sorted according to the provided Comparator.

For ordered streams, the sort is stable. For unordered streams, no stability guarantees are made.

This is a stateful intermediate operation.

Parameters:

comparator - a non-interfering, stateless DistributedComparator to be used to compare stream elements

Returns:

the new stream

peek

default DistributedStream<T> peek(DistributedConsumer<? super T> action)

Returns a stream consisting of the elements of this stream, additionally performing the provided action on each element as elements are consumed from the resulting stream.

This is an intermediate operation.

The action may be called at whatever time and in whatever thread the element is made available by the upstream operation. If the action modifies shared state, it is responsible for providing the required synchronization.

Parameters:

action - a non-interfering action to perform on the elements as they are consumed from the stream

Returns:

the new stream

limit

DistributedStream<T> limit(long maxSize)

Specified by:

limit in interface java.util.stream.Stream<T>

skip

DistributedStream<T> skip(long n)

Specified by:

skip in interface java.util.stream.Stream<T>

reduce

default T reduce(T identity,
                 DistributedBinaryOperator<T> accumulator)

Performs a reduction on the elements of this stream, using the provided identity value and an associative accumulation function, and returns the reduced value. This is equivalent to:

     T result = identity;
     for (T element : this stream)
         result = accumulator.apply(result, element)
     return result;
 

but is not constrained to execute sequentially.

The identity value must be an identity for the accumulator function. This means that for all t, accumulator.apply(identity, t) is equal to t. The accumulator function must be an associative function.

This is a terminal operation.

Parameters:

identity - the identity value for the accumulating function

accumulator - an associative, non-interfering, stateless function for combining two values

Returns:

the result of the reduction

reduce

default Optional<T> reduce(DistributedBinaryOperator<T> accumulator)

Performs a reduction on the elements of this stream, using an associative accumulation function, and returns an Optional describing the reduced value, if any. This is equivalent to:

     boolean foundAny = false;
     T result = null;
     for (T element : this stream) {
         if (!foundAny) {
             foundAny = true;
             result = element;
         }
         else
             result = accumulator.apply(result, element);
     }
     return foundAny ? Optional.of(result) : Optional.empty();
 

but is not constrained to execute sequentially.

The accumulator function must be an associative function.

This is a terminal operation.

Parameters:

accumulator - an associative, non-interfering, stateless function for combining two values

Returns:

an Optional describing the result of the reduction

Throws:

NullPointerException - if the result of the reduction is null

See Also:

reduce(Object, DistributedBinaryOperator), min(DistributedComparator), max(DistributedComparator)

reduce

default <U> U reduce(U identity,
                     DistributedBiFunction<U,? super T,U> accumulator,
                     DistributedBinaryOperator<U> combiner)

Performs a reduction on the elements of this stream, using the provided identity, accumulation and combining functions. This is equivalent to:

     U result = identity;
     for (T element : this stream)
         result = accumulator.apply(result, element)
     return result;
 

but is not constrained to execute sequentially.

The identity value must be an identity for the combiner function. This means that for all u, combiner(identity, u) is equal to u. Additionally, the combiner function must be compatible with the accumulator function; for all u and t, the following must hold:

     combiner.apply(u, accumulator.apply(identity, t)) == accumulator.apply(u, t)
 

This is a terminal operation.

Type Parameters:

U - The type of the result

Parameters:

identity - the identity value for the combiner function

accumulator - an associative, non-interfering, stateless function for incorporating an additional element into a result

combiner - an associative, non-interfering, stateless function for combining two values, which must be compatible with the accumulator function

Returns:

the result of the reduction

See Also:

reduce(DistributedBinaryOperator), reduce(Object, DistributedBinaryOperator)

collect

default <R> R collect(DistributedSupplier<R> supplier,
                      DistributedBiConsumer<R,? super T> accumulator,
                      DistributedBiConsumer<R,R> combiner)

Performs a mutable reduction operation on the elements of this stream. A mutable reduction is one in which the reduced value is a mutable result container, such as an ArrayList, and elements are incorporated by updating the state of the result rather than by replacing the result. This produces a result equivalent to:

     R result = supplier.get();
     for (T element : this stream)
         accumulator.accept(result, element);
     return result;
 

Like reduce(Object, DistributedBinaryOperator), collect operations can be parallelized without requiring additional synchronization.

This is a terminal operation.

Type Parameters:

R - type of the result

Parameters:

supplier - a function that creates a new result container. For a parallel execution, this function may be called multiple times and must return a fresh value each time.

accumulator - an associative, non-interfering, stateless function for incorporating an additional element into a result

combiner - an associative, non-interfering, stateless function for combining two values, which must be compatible with the accumulator function

Returns:

the result of the reduction

collect

default <R,A> R collect(DistributedCollector<? super T,A,R> collector)

Performs a mutable reduction operation on the elements of this stream using a DistributedCollector. A DistributedCollector encapsulates the functions used as arguments to collect(DistributedSupplier, DistributedBiConsumer, DistributedBiConsumer), allowing for reuse of collection strategies and composition of collect operations such as multiple-level grouping or partitioning.

This is a terminal operation.

When executed in parallel, multiple intermediate results may be instantiated, populated, and merged so as to maintain isolation of mutable data structures. Therefore, even when executed in parallel with non-thread-safe data structures (such as ArrayList), no additional synchronization is needed for a parallel reduction.

Type Parameters:

R - the type of the result

A - the intermediate accumulation type of the DistributedCollector

Parameters:

collector - the DistributedCollector describing the reduction

Returns:

the result of the reduction

See Also:

collect(Supplier, BiConsumer, BiConsumer), Collectors

collect

<R> R collect(DistributedCollector.Reducer<? super T,R> reducer)

Terminate the stream using a reduction performed by DistributedCollector.Reducer and return the resulting value. A DistributedCollector.Reducer is specific to Jet, and is responsible for building and executing the underlying DAG. It can't be used as a downstream collector in a collector cascade.

Type Parameters:

R - type of the return value

Parameters:

reducer - the reducer

Returns:

the result of the reduction operation

min

default Optional<T> min(DistributedComparator<? super T> comparator)

Returns the minimum element of this stream according to the provided DistributedComparator. This is a special case of a reduction.

This is a terminal operation.

Parameters:

comparator - a non-interfering, stateless DistributedComparator to compare elements of this stream

Returns:

an Optional describing the minimum element of this stream, or an empty Optional if the stream is empty

Throws:

NullPointerException - if the minimum element is null

max

default Optional<T> max(DistributedComparator<? super T> comparator)

Returns the maximum element of this stream according to the provided DistributedComparator. This is a special case of a reduction.

This is a terminal operation.

Parameters:

comparator - a non-interfering, stateless DistributedComparator to compare elements of this stream

Returns:

an Optional describing the maximum element of this stream, or an empty Optional if the stream is empty

Throws:

NullPointerException - if the maximum element is null

anyMatch

default boolean anyMatch(DistributedPredicate<? super T> predicate)

Returns whether any elements of this stream match the provided predicate. May not evaluate the predicate on all elements if not necessary for determining the result. If the stream is empty then false is returned and the predicate is not evaluated.

This is a short-circuiting terminal operation.

Parameters:

predicate - a non-interfering, stateless predicate to apply to elements of this stream

Returns:

true if any elements of the stream match the provided predicate, otherwise false

allMatch

default boolean allMatch(DistributedPredicate<? super T> predicate)

Returns whether all elements of this stream match the provided predicate. May not evaluate the predicate on all elements if not necessary for determining the result. If the stream is empty then true is returned and the predicate is not evaluated.

This is a short-circuiting terminal operation.

Parameters:

predicate - a non-interfering, stateless predicate to apply to elements of this stream

Returns:

true if either all elements of the stream match the provided predicate or the stream is empty, otherwise false

noneMatch

default boolean noneMatch(DistributedPredicate<? super T> predicate)

Returns whether no elements of this stream match the provided predicate. May not evaluate the predicate on all elements if not necessary for determining the result. If the stream is empty then true is returned and the predicate is not evaluated.

This is a short-circuiting terminal operation.

Parameters:

predicate - a non-interfering, stateless predicate to apply to elements of this stream

Returns:

true if either no elements of the stream match the provided predicate or the stream is empty, otherwise false

sequential

DistributedStream<T> sequential()

Specified by:

sequential in interface java.util.stream.BaseStream<T,java.util.stream.Stream<T>>

parallel

DistributedStream<T> parallel()

Specified by:

parallel in interface java.util.stream.BaseStream<T,java.util.stream.Stream<T>>

unordered

DistributedStream<T> unordered()

Specified by:

unordered in interface java.util.stream.BaseStream<T,java.util.stream.Stream<T>>

filter

DistributedStream<T> filter(java.util.function.Predicate<? super T> predicate)

Specified by:

filter in interface java.util.stream.Stream<T>

map

<R> DistributedStream<R> map(java.util.function.Function<? super T,? extends R> mapper)

Specified by:

map in interface java.util.stream.Stream<T>

mapToInt

DistributedIntStream mapToInt(java.util.function.ToIntFunction<? super T> mapper)

Specified by:

mapToInt in interface java.util.stream.Stream<T>

mapToLong

DistributedLongStream mapToLong(java.util.function.ToLongFunction<? super T> mapper)

Specified by:

mapToLong in interface java.util.stream.Stream<T>

mapToDouble

DistributedDoubleStream mapToDouble(java.util.function.ToDoubleFunction<? super T> mapper)

Specified by:

mapToDouble in interface java.util.stream.Stream<T>

flatMap

<R> DistributedStream<R> flatMap(java.util.function.Function<? super T,? extends java.util.stream.Stream<? extends R>> mapper)

Specified by:

flatMap in interface java.util.stream.Stream<T>

flatMapToInt

DistributedIntStream flatMapToInt(java.util.function.Function<? super T,? extends java.util.stream.IntStream> mapper)

Specified by:

flatMapToInt in interface java.util.stream.Stream<T>

flatMapToLong

DistributedLongStream flatMapToLong(java.util.function.Function<? super T,? extends java.util.stream.LongStream> mapper)

Specified by:

flatMapToLong in interface java.util.stream.Stream<T>

flatMapToDouble

DistributedDoubleStream flatMapToDouble(java.util.function.Function<? super T,? extends java.util.stream.DoubleStream> mapper)

Specified by:

flatMapToDouble in interface java.util.stream.Stream<T>

sorted

DistributedStream<T> sorted(Comparator<? super T> comparator)

Specified by:

sorted in interface java.util.stream.Stream<T>

peek

DistributedStream<T> peek(java.util.function.Consumer<? super T> action)

Specified by:

peek in interface java.util.stream.Stream<T>

reduce

T reduce(T identity,
         java.util.function.BinaryOperator<T> accumulator)

Specified by:

reduce in interface java.util.stream.Stream<T>

reduce

Optional<T> reduce(java.util.function.BinaryOperator<T> accumulator)

Specified by:

reduce in interface java.util.stream.Stream<T>

reduce

<U> U reduce(U identity,
             java.util.function.BiFunction<U,? super T,U> accumulator,
             java.util.function.BinaryOperator<U> combiner)

Specified by:

reduce in interface java.util.stream.Stream<T>

collect

<R> R collect(java.util.function.Supplier<R> supplier,
              java.util.function.BiConsumer<R,? super T> accumulator,
              java.util.function.BiConsumer<R,R> combiner)

Specified by:

collect in interface java.util.stream.Stream<T>

min

Optional<T> min(Comparator<? super T> comparator)

Specified by:

min in interface java.util.stream.Stream<T>

max

Optional<T> max(Comparator<? super T> comparator)

Specified by:

max in interface java.util.stream.Stream<T>

anyMatch

boolean anyMatch(java.util.function.Predicate<? super T> predicate)

Specified by:

anyMatch in interface java.util.stream.Stream<T>

allMatch

boolean allMatch(java.util.function.Predicate<? super T> predicate)

Specified by:

allMatch in interface java.util.stream.Stream<T>

noneMatch

boolean noneMatch(java.util.function.Predicate<? super T> predicate)

Specified by:

noneMatch in interface java.util.stream.Stream<T>

configure

DistributedStream<T> configure(JobConfig jobConfig)

Parameters:

jobConfig - Job configuration which will be used while executing underlying DAG

Returns:

the new stream