akka.stream.scaladsl

Class OrElse<T>

java.lang.Object

akka.stream.stage.GraphStageWithMaterializedValue<S,NotUsed>

akka.stream.stage.GraphStage<UniformFanInShape<T,T>>

akka.stream.scaladsl.OrElse<T>

All Implemented Interfaces:

Graph<UniformFanInShape<T,T>,NotUsed>

public final class OrElse<T>
extends GraphStage<UniformFanInShape<T,T>>

Takes two streams and passes the first through, the secondary stream is only passed through if the primary stream completes without passing any elements through. When the first element is passed through from the primary the secondary is cancelled. Both incoming streams are materialized when the stage is materialized.

On errors the stage is failed regardless of source of the error.

'''Emits when''' element is available from primary stream or the primary stream closed without emitting any elements and an element is available from the secondary stream

'''Backpressures when''' downstream backpressures

'''Completes when''' the primary stream completes after emitting at least one element, when the primary stream completes without emitting and the secondary stream already has completed or when the secondary stream completes

'''Cancels when''' downstream cancels

Constructor Summary

Constructors

Constructor and Description
OrElse()

Method Summary

Modifier and Type	Method and Description
static Graph<S,M>	addAttributes(Attributes attr)
static <T> OrElse<T>	apply()
static Graph<S,M>	async()
GraphStageLogic	createLogic(Attributes inheritedAttributes)
static scala.Tuple2<GraphStageLogic,NotUsed>	createLogicAndMaterializedValue(Attributes inheritedAttributes)
protected Attributes	initialAttributes()
static StreamLayout.Module	module()
static Graph<S,M>	named(java.lang.String name)
Outlet<T>	out()
Inlet<T>	primary()
Inlet<T>	secondary()
UniformFanInShape<T,T>	shape() The shape of a graph is all that is externally visible: its inlets and outlets.
java.lang.String	toString()
static Graph<S,M>	withAttributes(Attributes attr)

Methods inherited from class akka.stream.stage.GraphStage

createLogicAndMaterializedValue

Methods inherited from class akka.stream.stage.GraphStageWithMaterializedValue

module, withAttributes

Methods inherited from class java.lang.Object

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

Methods inherited from interface akka.stream.Graph

addAttributes, async, named

Constructor Detail

OrElse

public OrElse()

Method Detail

apply

public static <T> OrElse<T> apply()

named

public static Graph<S,M> named(java.lang.String name)

async

public static Graph<S,M> async()

addAttributes

public static Graph<S,M> addAttributes(Attributes attr)

module

public static final StreamLayout.Module module()

withAttributes

public static final Graph<S,M> withAttributes(Attributes attr)

createLogicAndMaterializedValue

public static final scala.Tuple2<GraphStageLogic,NotUsed> createLogicAndMaterializedValue(Attributes inheritedAttributes)

primary

public Inlet<T> primary()

secondary

public Inlet<T> secondary()

out

public Outlet<T> out()

shape

public UniformFanInShape<T,T> shape()

Description copied from interface: Graph

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

Returns:

(undocumented)

initialAttributes

protected Attributes initialAttributes()

Overrides:

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

createLogic

public GraphStageLogic createLogic(Attributes inheritedAttributes)

Specified by:

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

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object