akka.stream.Graph.scala Maven / Gradle / Ivy
/*
* Copyright (C) 2015-2020 Lightbend Inc.
*/
package akka.stream
import akka.annotation.InternalApi
import akka.stream.impl.TraversalBuilder
import scala.annotation.unchecked.uncheckedVariance
/**
* Not intended to be directly extended by user classes
*
* @see [[akka.stream.stage.GraphStage]]
*/
trait Graph[+S <: Shape, +M] {
/**
* Type-level accessor for the shape parameter of this graph.
*/
type Shape = S @uncheckedVariance
/**
* The shape of a graph is all that is externally visible: its inlets and outlets.
*/
def shape: S
/**
* INTERNAL API.
*
* Every materializable element must be backed by a stream layout module
*/
private[stream] def traversalBuilder: TraversalBuilder
def withAttributes(attr: Attributes): Graph[S, M]
def named(name: String): Graph[S, M] = addAttributes(Attributes.name(name))
/**
* Put an asynchronous boundary around this `Graph`
*/
def async: Graph[S, M] = addAttributes(Attributes.asyncBoundary)
/**
* Put an asynchronous boundary around this `Graph`
*
* @param dispatcher Run the graph on this dispatcher
*/
def async(dispatcher: String) =
addAttributes(Attributes.asyncBoundary and ActorAttributes.dispatcher(dispatcher))
/**
* Put an asynchronous boundary around this `Graph`
*
* @param dispatcher Run the graph on this dispatcher
* @param inputBufferSize Set the input buffer to this size for the graph
*/
def async(dispatcher: String, inputBufferSize: Int) =
addAttributes(
Attributes.asyncBoundary and ActorAttributes.dispatcher(dispatcher)
and Attributes.inputBuffer(inputBufferSize, inputBufferSize))
/**
* Add the given attributes to this [[Graph]]. If the specific attribute was already present
* on this graph this means the added attribute will be more specific than the existing one.
* If this Source is a composite of multiple graphs, new attributes on the composite will be
* less specific than attributes set directly on the individual graphs of the composite.
*/
def addAttributes(attr: Attributes): Graph[S, M] = withAttributes(traversalBuilder.attributes and attr)
}
/**
* INTERNAL API
*
* Allows creating additional API on top of an existing Graph by extending from this class and
* accessing the delegate
*/
@InternalApi
private[stream] abstract class GraphDelegate[+S <: Shape, +Mat](delegate: Graph[S, Mat]) extends Graph[S, Mat] {
final override def shape: S = delegate.shape
final override private[stream] def traversalBuilder: TraversalBuilder = delegate.traversalBuilder
}