akka.stream.javadsl

Class Sink$

java.lang.Object

akka.stream.javadsl.Sink$

public class Sink$
extends java.lang.Object

Java API

Field Summary

Fields

Modifier and Type	Field and Description
static Sink$	MODULE$ Static reference to the singleton instance of this Scala object.

Constructor Summary

Constructors

Constructor and Description
Sink$()

Method Summary

Modifier and Type	Method and Description
<In> Sink<In,NotUsed>	actorRef(ActorRef ref, java.lang.Object onCompleteMessage) Sends the elements of the stream to the given ActorRef.
<In> Sink<In,NotUsed>	actorRefWithAck(ActorRef ref, java.lang.Object onInitMessage, java.lang.Object ackMessage, java.lang.Object onCompleteMessage, Function<java.lang.Throwable,java.lang.Object> onFailureMessage) Sends the elements of the stream to the given ActorRef that sends back back-pressure signal.
<T> Sink<T,ActorRef>	actorSubscriber(Props props) Creates a Sink that is materialized to an ActorRef which points to an Actor created according to the passed in Props.
<T> Sink<T,org.reactivestreams.Publisher<T>>	asPublisher(AsPublisher fanout) A Sink that materializes into a Publisher.
<T> Sink<T,NotUsed>	cancelled() A Sink that immediately cancels its upstream after materialization.
<T,U> Sink<T,NotUsed>	combine(Sink<U,?> output1, Sink<U,?> output2, java.util.List<Sink<U,?>> rest, Function<java.lang.Integer,Graph<UniformFanOutShape<T,U>,NotUsed>> strategy) Combine several sinks with fan-out strategy like Broadcast or Balance and returns Sink.
<U,In> Sink<In,java.util.concurrent.CompletionStage<U>>	fold(U zero, Function2<U,In,U> f) A Sink that will invoke the given function for every received element, giving it its previous output (or the given zero value) and the element as input.
<U,In> Sink<In,java.util.concurrent.CompletionStage<U>>	foldAsync(U zero, Function2<U,In,java.util.concurrent.CompletionStage<U>> f) A Sink that will invoke the given asynchronous function for every received element, giving it its previous output (or the given zero value) and the element as input.
<T> Sink<T,java.util.concurrent.CompletionStage<Done>>	foreach(Procedure<T> f) A Sink that will invoke the given procedure for each received element.
<T> Sink<T,java.util.concurrent.CompletionStage<Done>>	foreachParallel(int parallel, Procedure<T> f, scala.concurrent.ExecutionContext ec) A Sink that will invoke the given procedure for each received element in parallel.
<T,M> Sink<T,M>	fromGraph(Graph<SinkShape<T>,M> g) A graph with the shape of a sink logically is a sink, this method makes it so also in type.
<In> Sink<In,NotUsed>	fromSubscriber(org.reactivestreams.Subscriber<In> subs) Helper to create Sink from Subscriber.
<In> Sink<In,java.util.concurrent.CompletionStage<In>>	head() A Sink that materializes into a CompletionStage of the first value received.
<In> Sink<In,java.util.concurrent.CompletionStage<java.util.Optional<In>>>	headOption() A Sink that materializes into a CompletionStage of the optional first value received.
<T> Sink<T,java.util.concurrent.CompletionStage<Done>>	ignore() A Sink that will consume the stream and discard the elements.
<In> Sink<In,java.util.concurrent.CompletionStage<In>>	last() A Sink that materializes into a CompletionStage of the last value received.
<In> Sink<In,java.util.concurrent.CompletionStage<java.util.Optional<In>>>	lastOption() A Sink that materializes into a CompletionStage of the optional last value received.
<T,M> Sink<T,java.util.concurrent.CompletionStage<M>>	lazyInit(Function<T,java.util.concurrent.CompletionStage<Sink<T,M>>> sinkFactory, Creator<M> fallback) Creates a real Sink upon receiving the first element.
<In> Sink<In,NotUsed>	onComplete(Procedure<scala.util.Try<Done>> callback) A Sink that when the flow is completed, either through a failure or normal completion, apply the provided function with Success or Failure.
<T> Sink<T,SinkQueueWithCancel<T>>	queue() Creates a Sink that is materialized as an SinkQueue.
<In> Sink<In,java.util.concurrent.CompletionStage<In>>	reduce(Function2<In,In,In> f) A Sink that will invoke the given function for every received element, giving it its previous output (from the second element) and the element as input.
<In> Sink<In,java.util.concurrent.CompletionStage<java.util.List<In>>>	seq() A Sink that keeps on collecting incoming elements until upstream terminates.

Methods inherited from class java.lang.Object

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

Field Detail

MODULE$

public static final Sink$ MODULE$

Static reference to the singleton instance of this Scala object.

Constructor Detail

Sink$

public Sink$()

Method Detail

fold

public <U,In> Sink<In,java.util.concurrent.CompletionStage<U>> fold(U zero,
                                                                    Function2<U,In,U> f)

A Sink that will invoke the given function for every received element, giving it its previous output (or the given zero value) and the element as input. The returned CompletionStage will be completed with value of the final function evaluation when the input stream ends, or completed with Failure if there is a failure is signaled in the stream.

Parameters:

zero - (undocumented)

f - (undocumented)

Returns:

(undocumented)

foldAsync

public <U,In> Sink<In,java.util.concurrent.CompletionStage<U>> foldAsync(U zero,
                                                                         Function2<U,In,java.util.concurrent.CompletionStage<U>> f)

A Sink that will invoke the given asynchronous function for every received element, giving it its previous output (or the given zero value) and the element as input. The returned CompletionStage will be completed with value of the final function evaluation when the input stream ends, or completed with Failure if there is a failure is signaled in the stream.

Parameters:

zero - (undocumented)

f - (undocumented)

Returns:

(undocumented)

reduce

public <In> Sink<In,java.util.concurrent.CompletionStage<In>> reduce(Function2<In,In,In> f)

A Sink that will invoke the given function for every received element, giving it its previous output (from the second element) and the element as input. The returned CompletionStage will be completed with value of the final function evaluation when the input stream ends, or completed with Failure if there is a failure signaled in the stream.

If the stream is empty (i.e. completes before signalling any elements), the reduce stage will fail its downstream with a NoSuchElementException, which is semantically in-line with that Scala's standard library collections do in such situations.

Parameters:

f - (undocumented)

Returns:

(undocumented)

fromSubscriber

public <In> Sink<In,NotUsed> fromSubscriber(org.reactivestreams.Subscriber<In> subs)

Helper to create Sink from Subscriber.

Parameters:

subs - (undocumented)

Returns:

(undocumented)

cancelled

public <T> Sink<T,NotUsed> cancelled()

A Sink that immediately cancels its upstream after materialization.

Returns:

(undocumented)

ignore

public <T> Sink<T,java.util.concurrent.CompletionStage<Done>> ignore()

A Sink that will consume the stream and discard the elements.

Returns:

(undocumented)

asPublisher

public <T> Sink<T,org.reactivestreams.Publisher<T>> asPublisher(AsPublisher fanout)

A Sink that materializes into a Publisher.

If fanout is true, the materialized Publisher will support multiple Subscribers and the size of the inputBuffer configured for this stage becomes the maximum number of elements that the fastest Subscriber can be ahead of the slowest one before slowing the processing down due to back pressure.

If fanout is false then the materialized Publisher will only support a single Subscriber and reject any additional Subscribers.

Parameters:

fanout - (undocumented)

Returns:

(undocumented)

foreach

public <T> Sink<T,java.util.concurrent.CompletionStage<Done>> foreach(Procedure<T> f)

A Sink that will invoke the given procedure for each received element. The sink is materialized into a CompletionStage will be completed with Success when reaching the normal end of the stream, or completed with Failure if there is a failure is signaled in the stream..

Parameters:

f - (undocumented)

Returns:

(undocumented)

foreachParallel

public <T> Sink<T,java.util.concurrent.CompletionStage<Done>> foreachParallel(int parallel,
                                                                              Procedure<T> f,
                                                                              scala.concurrent.ExecutionContext ec)

A Sink that will invoke the given procedure for each received element in parallel. The sink is materialized into a CompletionStage.

If f throws an exception and the supervision decision is akka.stream.Supervision.Stop the CompletionStage will be completed with failure.

If f throws an exception and the supervision decision is akka.stream.Supervision.Resume or akka.stream.Supervision.Restart the element is dropped and the stream continues.

Parameters:

parallel - (undocumented)

f - (undocumented)

ec - (undocumented)

Returns:

(undocumented)

onComplete

public <In> Sink<In,NotUsed> onComplete(Procedure<scala.util.Try<Done>> callback)

A Sink that when the flow is completed, either through a failure or normal completion, apply the provided function with Success or Failure.

Parameters:

callback - (undocumented)

Returns:

(undocumented)

head

public <In> Sink<In,java.util.concurrent.CompletionStage<In>> head()

A Sink that materializes into a CompletionStage of the first value received. If the stream completes before signaling at least a single element, the CompletionStage will be failed with a NoSuchElementException. If the stream signals an error before signaling at least a single element, the CompletionStage will be failed with the streams exception.

See also headOption.

Returns:

(undocumented)

headOption

public <In> Sink<In,java.util.concurrent.CompletionStage<java.util.Optional<In>>> headOption()

A Sink that materializes into a CompletionStage of the optional first value received. If the stream completes before signaling at least a single element, the value of the CompletionStage will be an empty Optional. If the stream signals an error errors before signaling at least a single element, the CompletionStage will be failed with the streams exception.

See also head.

Returns:

(undocumented)

last

public <In> Sink<In,java.util.concurrent.CompletionStage<In>> last()

A Sink that materializes into a CompletionStage of the last value received. If the stream completes before signaling at least a single element, the CompletionStage will be failed with a NoSuchElementException. If the stream signals an error errors before signaling at least a single element, the CompletionStage will be failed with the streams exception.

See also lastOption.

Returns:

(undocumented)

lastOption

public <In> Sink<In,java.util.concurrent.CompletionStage<java.util.Optional<In>>> lastOption()

A Sink that materializes into a CompletionStage of the optional last value received. If the stream completes before signaling at least a single element, the value of the CompletionStage will be an empty Optional. If the stream signals an error errors before signaling at least a single element, the CompletionStage will be failed with the streams exception.

See also head.

Returns:

(undocumented)

seq

public <In> Sink<In,java.util.concurrent.CompletionStage<java.util.List<In>>> seq()

A Sink that keeps on collecting incoming elements until upstream terminates. As upstream may be unbounded, Flow[T].take or the stricter Flow[T].limit (and their variants) may be used to ensure boundedness. Materializes into a CompletionStage of Seq[T] containing all the collected elements. List is limited to Integer.MAX_VALUE elements, this Sink will cancel the stream after having received that many elements.

See also Flow.limit, Flow.limitWeighted, Flow.take, Flow.takeWithin, Flow.takeWhile

Returns:

(undocumented)

actorRef

public <In> Sink<In,NotUsed> actorRef(ActorRef ref,
                                      java.lang.Object onCompleteMessage)

Sends the elements of the stream to the given ActorRef. If the target actor terminates the stream will be canceled. When the stream is completed successfully the given onCompleteMessage will be sent to the destination actor. When the stream is completed with failure a Status.Failure message will be sent to the destination actor.

It will request at most maxInputBufferSize number of elements from upstream, but there is no back-pressure signal from the destination actor, i.e. if the actor is not consuming the messages fast enough the mailbox of the actor will grow. For potentially slow consumer actors it is recommended to use a bounded mailbox with zero mailbox-push-timeout-time or use a rate limiting stage in front of this Sink.

Parameters:

ref - (undocumented)

onCompleteMessage - (undocumented)

Returns:

(undocumented)

actorRefWithAck

public <In> Sink<In,NotUsed> actorRefWithAck(ActorRef ref,
                                             java.lang.Object onInitMessage,
                                             java.lang.Object ackMessage,
                                             java.lang.Object onCompleteMessage,
                                             Function<java.lang.Throwable,java.lang.Object> onFailureMessage)

Sends the elements of the stream to the given ActorRef that sends back back-pressure signal. First element is always onInitMessage, then stream is waiting for acknowledgement message ackMessage from the given actor which means that it is ready to process elements. It also requires ackMessage message after each stream element to make backpressure work.

If the target actor terminates the stream will be canceled. When the stream is completed successfully the given onCompleteMessage will be sent to the destination actor. When the stream is completed with failure - result of onFailureMessage(throwable) message will be sent to the destination actor.

Parameters:

ref - (undocumented)

onInitMessage - (undocumented)

ackMessage - (undocumented)

onCompleteMessage - (undocumented)

onFailureMessage - (undocumented)

Returns:

(undocumented)

actorSubscriber

public <T> Sink<T,ActorRef> actorSubscriber(Props props)

Creates a Sink that is materialized to an ActorRef which points to an Actor created according to the passed in Props. Actor created by the props should be ActorSubscriber.

Parameters:

props - (undocumented)

Returns:

(undocumented)

fromGraph

public <T,M> Sink<T,M> fromGraph(Graph<SinkShape<T>,M> g)

A graph with the shape of a sink logically is a sink, this method makes it so also in type.

Parameters:

g - (undocumented)

Returns:

(undocumented)

combine

public <T,U> Sink<T,NotUsed> combine(Sink<U,?> output1,
                                     Sink<U,?> output2,
                                     java.util.List<Sink<U,?>> rest,
                                     Function<java.lang.Integer,Graph<UniformFanOutShape<T,U>,NotUsed>> strategy)

Combine several sinks with fan-out strategy like Broadcast or Balance and returns Sink.

Parameters:

output1 - (undocumented)

output2 - (undocumented)

rest - (undocumented)

strategy - (undocumented)

Returns:

(undocumented)

queue

public <T> Sink<T,SinkQueueWithCancel<T>> queue()

Creates a Sink that is materialized as an SinkQueue. akka.stream.javadsl.SinkQueue.pull method is pulling element from the stream and returns CompletionStage[Option[T}. CompletionStage completes when element is available.

Before calling pull method second time you need to wait until previous CompletionStage completes. Pull returns Failed future with ''IllegalStateException'' if previous future has not yet completed.

Sink will request at most number of elements equal to size of inputBuffer from upstream and then stop back pressure. You can configure size of input buffer by using Sink.withAttributes method.

For stream completion you need to pull all elements from SinkQueue including last None as completion marker

Returns:

(undocumented)

See Also:

SinkQueueWithCancel

lazyInit

public <T,M> Sink<T,java.util.concurrent.CompletionStage<M>> lazyInit(Function<T,java.util.concurrent.CompletionStage<Sink<T,M>>> sinkFactory,
                                                                      Creator<M> fallback)

Creates a real Sink upon receiving the first element. Internal Sink will not be created if there are no elements, because of completion or error.

If sinkFactory throws an exception and the supervision decision is akka.stream.Supervision.Stop the Future will be completed with failure. For all other supervision options it will try to create sink with next element

fallback will be executed when there was no elements and completed is received from upstream.

Parameters:

sinkFactory - (undocumented)

fallback - (undocumented)

Returns:

(undocumented)