92 lines
3.1 KiB
Scala
92 lines
3.1 KiB
Scala
/**
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* Copyright (C) 2015-2017 Lightbend Inc. <http://www.lightbend.com>
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*/
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package docs.stream
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import scala.concurrent.Await
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import akka.stream.ActorMaterializer
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import akka.stream.ActorMaterializerSettings
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import akka.stream.Supervision
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import akka.stream.scaladsl._
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import akka.testkit.AkkaSpec
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import akka.stream.Attributes
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import akka.stream.ActorAttributes
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import scala.concurrent.duration._
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class FlowErrorDocSpec extends AkkaSpec {
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"demonstrate fail stream" in {
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//#stop
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implicit val materializer = ActorMaterializer()
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val source = Source(0 to 5).map(100 / _)
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val result = source.runWith(Sink.fold(0)(_ + _))
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// division by zero will fail the stream and the
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// result here will be a Future completed with Failure(ArithmeticException)
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//#stop
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intercept[ArithmeticException] {
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Await.result(result, 3.seconds)
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}
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}
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"demonstrate resume stream" in {
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//#resume
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val decider: Supervision.Decider = {
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case _: ArithmeticException => Supervision.Resume
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case _ => Supervision.Stop
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}
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implicit val materializer = ActorMaterializer(
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ActorMaterializerSettings(system).withSupervisionStrategy(decider))
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val source = Source(0 to 5).map(100 / _)
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val result = source.runWith(Sink.fold(0)(_ + _))
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// the element causing division by zero will be dropped
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// result here will be a Future completed with Success(228)
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//#resume
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Await.result(result, 3.seconds) should be(228)
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}
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"demonstrate resume section" in {
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//#resume-section
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implicit val materializer = ActorMaterializer()
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val decider: Supervision.Decider = {
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case _: ArithmeticException => Supervision.Resume
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case _ => Supervision.Stop
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}
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val flow = Flow[Int]
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.filter(100 / _ < 50).map(elem => 100 / (5 - elem))
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.withAttributes(ActorAttributes.supervisionStrategy(decider))
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val source = Source(0 to 5).via(flow)
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val result = source.runWith(Sink.fold(0)(_ + _))
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// the elements causing division by zero will be dropped
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// result here will be a Future completed with Success(150)
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//#resume-section
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Await.result(result, 3.seconds) should be(150)
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}
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"demonstrate restart section" in {
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//#restart-section
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implicit val materializer = ActorMaterializer()
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val decider: Supervision.Decider = {
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case _: IllegalArgumentException => Supervision.Restart
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case _ => Supervision.Stop
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}
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val flow = Flow[Int]
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.scan(0) { (acc, elem) =>
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if (elem < 0) throw new IllegalArgumentException("negative not allowed")
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else acc + elem
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}
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.withAttributes(ActorAttributes.supervisionStrategy(decider))
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val source = Source(List(1, 3, -1, 5, 7)).via(flow)
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val result = source.limit(1000).runWith(Sink.seq)
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// the negative element cause the scan stage to be restarted,
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// i.e. start from 0 again
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// result here will be a Future completed with Success(Vector(0, 1, 4, 0, 5, 12))
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//#restart-section
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Await.result(result, 3.seconds) should be(Vector(0, 1, 4, 0, 5, 12))
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}
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}
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