=str Reduce some Inhandler and Outhandler allocation. (#31278)

akka-stream/src/main/scala/akka/stream/impl/io/OutputStreamSourceStage.scala

@@ -56,9 +56,7 @@ final private[stream] class OutputStreamSourceStage(writeTimeout: FiniteDuration
         }
       }
 
-      setHandler(out, new OutHandler {
+      setHandler(out, GraphStageLogic.EagerTerminateOutput)
-        override def onPull(): Unit = {}
-      })
     }
 
     val logic = new OutputStreamSourceLogic

akka-stream/src/main/scala/akka/stream/impl/io/TcpStages.scala

@@ -272,9 +272,7 @@ private[stream] object ConnectionSourceStage {
     private var previousWriteBufferSize = 0
 
     // No reading until role have been decided
-    setHandler(bytesOut, new OutHandler {
+    setHandler(bytesOut, GraphStageLogic.EagerTerminateOutput)
-      override def onPull(): Unit = ()
-    })
 
     override def preStart(): Unit = {
       setKeepGoing(true)

akka-stream/src/main/scala/akka/stream/scaladsl/RestartFlow.scala

@@ -215,12 +215,8 @@ private final class RestartWithBackoffFlow[In, Out](
       }
 
       override protected def backoff() = {
-        setHandler(in, new InHandler {
+        setHandler(in, GraphStageLogic.EagerTerminateInput)
-          override def onPush() = ()
+        setHandler(out, GraphStageLogic.EagerTerminateOutput)
-        })
-        setHandler(out, new OutHandler {
-          override def onPull() = ()
-        })
 
         // We need to ensure that the other end of the sub flow is also completed, so that we don't
         // receive any callbacks from it.
@@ -462,9 +458,7 @@ object RestartWithBackoffFlow {
         override def onDownstreamFinish(cause: Throwable): Unit = {
           this.cause = OptionVal.Some(cause)
           scheduleOnce("CompleteState", delay)
-          setHandler(in, new InHandler {
+          setHandler(in, GraphStageLogic.EagerTerminateInput)
-            def onPush(): Unit = {}
-          })
         }
 
         override protected def onTimer(timerKey: Any): Unit = {

akka-stream/src/main/scala/akka/stream/scaladsl/RestartSink.scala

@@ -4,11 +4,11 @@
 
 package akka.stream.scaladsl
 
-import scala.concurrent.duration.FiniteDuration
-
 import akka.NotUsed
+import akka.stream.stage.{ GraphStage, GraphStageLogic }
 import akka.stream.{ Attributes, Inlet, RestartSettings, SinkShape }
-import akka.stream.stage.{ GraphStage, InHandler }
+
+import scala.concurrent.duration.FiniteDuration
 
 /**
  * A RestartSink wraps a [[Sink]] that gets restarted when it completes or fails.
@@ -124,9 +124,7 @@ private final class RestartWithBackoffSink[T](sinkFactory: () => Sink[T, _], res
       }
 
       override protected def backoff() = {
-        setHandler(in, new InHandler {
+        setHandler(in, GraphStageLogic.EagerTerminateInput)
-          override def onPush() = ()
-        })
       }
 
       backoff()

akka-stream/src/main/scala/akka/stream/scaladsl/RestartSource.scala

@@ -4,11 +4,11 @@
 
 package akka.stream.scaladsl
 
-import scala.concurrent.duration.FiniteDuration
-
 import akka.NotUsed
+import akka.stream.stage.{ GraphStage, GraphStageLogic }
 import akka.stream.{ Attributes, Outlet, RestartSettings, SourceShape }
-import akka.stream.stage.{ GraphStage, OutHandler }
+
+import scala.concurrent.duration.FiniteDuration
 
 /**
  * A RestartSource wraps a [[Source]] that gets restarted when it completes or fails.
@@ -203,9 +203,7 @@ private final class RestartWithBackoffSource[T](
       }
 
       override protected def backoff() = {
-        setHandler(out, new OutHandler {
+        setHandler(out, GraphStageLogic.EagerTerminateOutput)
-          override def onPull() = ()
-        })
       }
 
       backoff()

akka-stream/src/main/scala/akka/stream/stage/GraphStage.scala

@@ -533,12 +533,10 @@ abstract class GraphStageLogic private[stream] (val inCount: Int, val outCount:
   private def cancel[T](connection: Connection, cause: Throwable): Unit =
     attributes.mandatoryAttribute[Attributes.CancellationStrategy].strategy match {
       case Attributes.CancellationStrategy.AfterDelay(delay, _) =>
-        // since the port is not actually cancelled, we install a handler to ignore upcoming elements
+        // since the port is not actually cancelled, we install a handler to ignore upcoming
-        connection.inHandler = new InHandler {
         // ignore pushs now, since the stage wanted it cancelled already
-          override def onPush(): Unit = ()
         // do not ignore termination signals
-        }
+        connection.inHandler = EagerTerminateInput
         val callback = getAsyncCallback[(Connection, Throwable)] {
           case (connection, cause) => doCancel(connection, cause)
         }