50 lines
2 KiB
Scala
50 lines
2 KiB
Scala
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/**
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* Copyright (C) 2018 Lightbend Inc. <http://www.lightbend.com>
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*/
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package akka.stream.impl.streamref
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import akka.NotUsed
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import akka.annotation.InternalApi
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import akka.stream.scaladsl.Source
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import akka.stream.{ SourceRef, javadsl }
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import scala.concurrent.{ ExecutionContext, Future }
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import scala.util.{ Failure, Success }
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/**
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* INTERNAL API
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* Allows users to directly use the SourceRef, even though we do have to go through the Future in order to be able
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* to materialize it. Since we initialize the ref from within the GraphStageLogic. See [[SourceRefStageImpl]] for usage.
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*/
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@InternalApi
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private[akka] final case class MaterializedSourceRef[Out](futureSource: Future[SourceRefImpl[Out]]) extends SourceRef[Out] {
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override def source: Source[Out, NotUsed] =
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futureSource.value match {
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case Some(Success(ready)) ⇒
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// the normal case, since once materialization finishes, the future is guaranteed to have been completed
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ready.source
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case Some(Failure(cause)) ⇒
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// materialization failed
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Source.failed(cause).named("SourceRef")
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case None ⇒
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throw new Exception(s"This should not be possible! We guarantee to complete the materialized Future value when materialization finishes! Source was: $futureSource")
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// // not yet materialized -- in reality this case should not happen, since once materialization is finished, this Future is already completed
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// // this impl is kept in case materialization semantics would change for some reason
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// Source.fromFutureSource(futureSource.map(ref => ref.source)(ex)).mapMaterializedValue(_ ⇒ NotUsed)
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}
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override def getSource: javadsl.Source[Out, NotUsed] = source.asJava
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override def toString: String =
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futureSource.value match {
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case None ⇒ s"SourceRef(<materializing-source-ref>)"
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case Some(Success(ready)) ⇒ ready.toString
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case Some(Failure(ex)) ⇒ s"SourceRef(<failed:${ex.getMessage}>)"
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}
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}
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