Package org.apache.pekko.stream.scaladsl

Class Balance<T>

java.lang.Object

org.apache.pekko.stream.stage.GraphStageWithMaterializedValue<S,NotUsed>

org.apache.pekko.stream.stage.GraphStage<UniformFanOutShape<T,T>>

org.apache.pekko.stream.scaladsl.Balance<T>

All Implemented Interfaces:

Graph<UniformFanOutShape<T,T>,NotUsed>

public final class Balance<T>
extends GraphStage<UniformFanOutShape<T,T>>

Fan-out the stream to several streams. Each upstream element is emitted to the first available downstream consumer. It will not shut down until the subscriptions for at least two downstream subscribers have been established.

A Balance has one in port and 2 or more out ports.

'''Emits when''' any of the outputs stops backpressuring; emits the element to the first available output

'''Backpressures when''' all of the outputs backpressure

'''Completes when''' upstream completes

'''Cancels when''' If eagerCancel is enabled: when any downstream cancels; otherwise: when all downstreams cancel

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.pekko.stream.Graph

Graph.GraphMapMatVal<S extends Shape,M>

Constructor Summary

Constructors

Constructor	Description
Balance(int outputPorts, boolean waitForAllDownstreams, boolean eagerCancel)

Method Summary

Modifier and Type	Method	Description
static <T> Balance<T>	apply(int outputPorts, boolean waitForAllDownstreams)	Create a new Balance with the specified number of output ports.
static <T> boolean	apply$default$2()
GraphStageLogic	createLogic(Attributes inheritedAttributes)
boolean	eagerCancel()
Inlet<T>	in()
Attributes	initialAttributes()
scala.collection.immutable.IndexedSeq<Outlet<T>>	out()
int	outputPorts()
UniformFanOutShape<T,T>	shape()	The shape of a graph is all that is externally visible: its inlets and outlets.
String	toString()
boolean	waitForAllDownstreams()

Methods inherited from class org.apache.pekko.stream.stage.GraphStage

createLogicAndMaterializedValue

Methods inherited from class org.apache.pekko.stream.stage.GraphStageWithMaterializedValue

withAttributes

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.pekko.stream.Graph

addAttributes, async, async, async, getAttributes, named

Constructor Details

Balance

public Balance(int outputPorts,
 boolean waitForAllDownstreams,
 boolean eagerCancel)

Method Details

apply

public static <T> Balance<T> apply(int outputPorts,
 boolean waitForAllDownstreams)

Create a new Balance with the specified number of output ports. This method sets eagerCancel to false. To specify a different value for the eagerCancel parameter, then instantiate Balance using the constructor.

If eagerCancel is true, balance cancels upstream if any of its downstreams cancel, if false, when all have cancelled.

Parameters:

outputPorts - number of output ports

waitForAllDownstreams - if you use waitForAllDownstreams = true it will not start emitting elements to downstream outputs until all of them have requested at least one element, default value is false

apply$default$2

public static <T> boolean apply$default$2()

outputPorts

public int outputPorts()

waitForAllDownstreams

public boolean waitForAllDownstreams()

eagerCancel

public boolean eagerCancel()

in

public Inlet<T> in()

out

public scala.collection.immutable.IndexedSeq<Outlet<T>> out()

initialAttributes

public Attributes initialAttributes()

Overrides:

initialAttributes in class GraphStageWithMaterializedValue<UniformFanOutShape<T,T>,NotUsed>

shape

public UniformFanOutShape<T,T> shape()

Description copied from interface: Graph

The shape of a graph is all that is externally visible: its inlets and outlets.

createLogic

public GraphStageLogic createLogic(Attributes inheritedAttributes)

Specified by:

createLogic in class GraphStage<UniformFanOutShape<T,T>>

toString

public String toString()

Overrides:

toString in class Object