migrating Doubler, KeepGoing to GraphStage

akka-docs/rst/scala/code/docs/http/scaladsl/HttpServerExampleSpec.scala

@@ -132,7 +132,7 @@ class HttpServerExampleSpec extends WordSpec with Matchers
   "connection-stream-failure-handling" in compileOnlySpec {
     import akka.actor.ActorSystem
     import akka.http.scaladsl.Http
-    import akka.http.scaladsl.model.{ContentTypes, HttpEntity}
+    import akka.http.scaladsl.model.{ ContentTypes, HttpEntity }
     import akka.stream.ActorMaterializer
 
     implicit val system = ActorSystem()

akka-stream-tests/src/test/scala/akka/stream/impl/fusing/InterpreterSpec.scala

@@ -8,7 +8,7 @@ import akka.stream.stage._
 import akka.testkit.AkkaSpec
 import akka.testkit.EventFilter
 
-import akka.stream.Supervision
+import akka.stream._
 
 class InterpreterSpec extends AkkaSpec with GraphInterpreterSpecKit {
   import Supervision.stoppingDecider
@@ -80,7 +80,7 @@ class InterpreterSpec extends AkkaSpec with GraphInterpreterSpecKit {
     }
 
     "implement one-to-many many-to-one chain correctly" in new OneBoundedSetup[Int](
-      Doubler().toGS,
+      Doubler(),
       Filter((x: Int) ⇒ x != 0)) {
 
       lastEvents() should be(Set.empty)
@@ -106,7 +106,7 @@ class InterpreterSpec extends AkkaSpec with GraphInterpreterSpecKit {
 
     "implement many-to-one one-to-many chain correctly" in new OneBoundedSetup[Int](
       Filter((x: Int) ⇒ x != 0),
-      Doubler().toGS) {
+      Doubler()) {
 
       lastEvents() should be(Set.empty)
 
@@ -412,7 +412,7 @@ class InterpreterSpec extends AkkaSpec with GraphInterpreterSpecKit {
     }
 
     "implement doubler-conflate (doubler-batch)" in new OneBoundedSetup[Int](
-      Doubler().toGS,
+      Doubler(),
       Batch(
         1L,
         ConstantFun.zeroLong,
@@ -432,12 +432,12 @@ class InterpreterSpec extends AkkaSpec with GraphInterpreterSpecKit {
     }
 
     // Note, the new interpreter has no jumpback table, still did not want to remove the test
-    "work with jumpback table and completed elements" in new OneBoundedSetup[Int](Seq(
+    "work with jumpback table and completed elements" in new OneBoundedSetup[Int](
-      Map((x: Int) ⇒ x, stoppingDecider),
+      Map((x: Int) ⇒ x, stoppingDecider).toGS,
-      Map((x: Int) ⇒ x, stoppingDecider),
+      Map((x: Int) ⇒ x, stoppingDecider).toGS,
       KeepGoing(),
-      Map((x: Int) ⇒ x, stoppingDecider),
+      Map((x: Int) ⇒ x, stoppingDecider).toGS,
-      Map((x: Int) ⇒ x, stoppingDecider))) {
+      Map((x: Int) ⇒ x, stoppingDecider).toGS) {
 
       lastEvents() should be(Set.empty)
 
@@ -569,39 +569,67 @@ class InterpreterSpec extends AkkaSpec with GraphInterpreterSpecKit {
 
   }
 
-  private[akka] case class Doubler[T]() extends PushPullStage[T, T] {
+  private[akka] final case class Doubler[T]() extends GraphStage[FlowShape[T, T]] {
-    var oneMore: Boolean = false
+    val out: Outlet[T] = Outlet("Doubler.out")
-    var lastElem: T = _
+    val in: Inlet[T] = Inlet("Doubler.in")
 
-    override def onPush(elem: T, ctx: Context[T]): SyncDirective = {
+    override def createLogic(inheritedAttributes: Attributes): GraphStageLogic =
-      lastElem = elem
+      new GraphStageLogic(shape) with InHandler with OutHandler {
-      oneMore = true
+        var latest: T = _
-      ctx.push(elem)
+        var oneMore = false
-    }
 
-    override def onPull(ctx: Context[T]): SyncDirective = {
+        override def onPush(): Unit = {
-      if (oneMore) {
+          latest = grab(in)
-        oneMore = false
+          oneMore = true
-        ctx.push(lastElem)
+          push(out, latest)
-      } else ctx.pull()
+        }
-    }
+
+        /**
+         * Called when the output port has received a pull, and therefore ready to emit an element, i.e. [[GraphStageLogic.push()]]
+         * is now allowed to be called on this port.
+         */
+        override def onPull(): Unit = {
+          if (oneMore) {
+            push(out, latest)
+            oneMore = false
+          } else {
+            pull(in)
+          }
+        }
+
+        setHandlers(in, out, this)
+      }
+
+    override val shape: FlowShape[T, T] =  FlowShape(in, out)
   }
 
-  private[akka] case class KeepGoing[T]() extends PushPullStage[T, T] {
+  private[akka] final case class KeepGoing[T]() extends GraphStage[FlowShape[T, T]] {
-    var lastElem: T = _
+    val in = Inlet[T]("KeepGoing.in")
+    val out = Outlet[T]("KeepGoing.out")
 
-    override def onPush(elem: T, ctx: Context[T]): SyncDirective = {
+    override def createLogic(inheritedAttributes: Attributes): GraphStageLogic =
-      lastElem = elem
+      new GraphStageLogic(shape) with InHandler with OutHandler {
-      ctx.push(elem)
+        var lastElem: T = _
-    }
 
-    override def onPull(ctx: Context[T]): SyncDirective = {
+        override def onPush(): Unit = {
-      if (ctx.isFinishing) {
+          lastElem = grab(in)
-        ctx.push(lastElem)
+          push(out, lastElem)
-      } else ctx.pull()
+        }
-    }
 
-    override def onUpstreamFinish(ctx: Context[T]): TerminationDirective = ctx.absorbTermination()
+        override def onPull(): Unit = {
+          if (isClosed(in)) {
+            push(out, lastElem)
+          } else {
+            pull(in)
+          }
+        }
+
+        override def onUpstreamFinish(): Unit = {}
+
+        setHandlers(in, out, this)
+      }
+
+    override val shape: FlowShape[T, T] = FlowShape(in, out)
   }
 
   // This test is related to issue #17351