diff --git a/akka-stream/src/main/scala/akka/stream/FlowMaterializer.scala b/akka-stream/src/main/scala/akka/stream/FlowMaterializer.scala
index 5272ca50d8..e877a89598 100644
--- a/akka-stream/src/main/scala/akka/stream/FlowMaterializer.scala
+++ b/akka-stream/src/main/scala/akka/stream/FlowMaterializer.scala
@@ -14,8 +14,7 @@ object FlowMaterializer {
    * Scala API: Creates a FlowMaterializer which will execute every step of a transformation
    * pipeline within its own [[akka.actor.Actor]]. The required [[akka.actor.ActorRefFactory]]
    * (which can be either an [[akka.actor.ActorSystem]] or an [[akka.actor.ActorContext]])
-   * will be used to create these actors, therefore it is *forbidden* to pass this object
-   * to another actor if the factory is an ActorContext.
+   * will be used to create one actor that in turn creates actors for the transformation steps.
    *
    * The materializer's [[akka.stream.MaterializerSettings]] will be obtained from the
    * configuration of the `context`'s underlying [[akka.actor.ActorSystem]].
@@ -83,8 +82,7 @@ object FlowMaterializer {
    * Java API: Creates a FlowMaterializer which will execute every step of a transformation
    * pipeline within its own [[akka.actor.Actor]]. The required [[akka.actor.ActorRefFactory]]
    * (which can be either an [[akka.actor.ActorSystem]] or an [[akka.actor.ActorContext]])
-   * will be used to create these actors, therefore it is *forbidden* to pass this object
-   * to another actor if the factory is an ActorContext.
+   * will be used to create one actor that in turn creates actors for the transformation steps.
    */
   def create(settings: MaterializerSettings, context: ActorRefFactory): FlowMaterializer =
     apply(Option(settings), None)(context)
diff --git a/akka-stream/src/main/scala/akka/stream/impl/Transfer.scala b/akka-stream/src/main/scala/akka/stream/impl/Transfer.scala
index 81c24b131f..6eb6390d57 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/Transfer.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/Transfer.scala
@@ -1,5 +1,5 @@
 /**
- * Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
+ * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
  */
 package akka.stream.impl
 
diff --git a/akka-stream/src/main/scala/akka/stream/impl2/ActorBasedFlowMaterializer.scala b/akka-stream/src/main/scala/akka/stream/impl2/ActorBasedFlowMaterializer.scala
index a6024b9f51..4bc842d927 100644
--- a/akka-stream/src/main/scala/akka/stream/impl2/ActorBasedFlowMaterializer.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl2/ActorBasedFlowMaterializer.scala
@@ -21,6 +21,9 @@ import akka.stream.impl.IterablePublisher
 import akka.stream.impl.TransformProcessorImpl
 import akka.stream.impl.ActorProcessor
 import akka.stream.impl.ExposedPublisher
+import akka.stream.scaladsl2.Source
+import akka.stream.scaladsl2.Sink
+import akka.stream.scaladsl2.MaterializedFlow
 
 /**
  * INTERNAL API
@@ -32,21 +35,6 @@ private[akka] object Ast {
 
   case class Transform(name: String, mkTransformer: () ⇒ Transformer[Any, Any]) extends AstNode
 
-  trait PublisherNode[I] {
-    private[akka] def createPublisher(materializer: ActorBasedFlowMaterializer, flowName: String): Publisher[I]
-  }
-
-  final case class ExistingPublisher[I](publisher: Publisher[I]) extends PublisherNode[I] {
-    def createPublisher(materializer: ActorBasedFlowMaterializer, flowName: String) = publisher
-  }
-
-  final case class IterablePublisherNode[I](iterable: immutable.Iterable[I]) extends PublisherNode[I] {
-    def createPublisher(materializer: ActorBasedFlowMaterializer, flowName: String): Publisher[I] =
-      if (iterable.isEmpty) EmptyPublisher.asInstanceOf[Publisher[I]]
-      else ActorPublisher[I](materializer.actorOf(IterablePublisher.props(iterable, materializer.settings),
-        name = s"$flowName-0-iterable"), Some(iterable))
-  }
-
 }
 
 /**
@@ -78,29 +66,36 @@ private[akka] case class ActorBasedFlowMaterializer(
   }
 
   // Ops come in reverse order
-  override def toPublisher[I, O](publisherNode: PublisherNode[I], ops: List[AstNode]): Publisher[O] = {
+  override def materialize[In, Out](source: Source[In], sink: Sink[Out], ops: List[Ast.AstNode]): MaterializedFlow = {
     val flowName = createFlowName()
-    if (ops.isEmpty) publisherNode.createPublisher(this, flowName).asInstanceOf[Publisher[O]]
-    else {
-      val opsSize = ops.size
-      val opProcessor = processorForNode(ops.head, flowName, opsSize)
-      val topSubscriber = processorChain(opProcessor, ops.tail, flowName, opsSize - 1)
-      publisherNode.createPublisher(this, flowName).subscribe(topSubscriber.asInstanceOf[Subscriber[I]])
-      opProcessor.asInstanceOf[Publisher[O]]
-    }
+    val (sourcePublisher, sourceValue) = source.materialize(this, flowName)
+    val p =
+      if (ops.isEmpty) sourcePublisher.asInstanceOf[Publisher[Out]]
+      else {
+        val opsSize = ops.size
+        val opProcessor = processorForNode(ops.head, flowName, opsSize)
+        val topSubscriber = processorChain(opProcessor, ops.tail, flowName, opsSize - 1)
+        sourcePublisher.subscribe(topSubscriber.asInstanceOf[Subscriber[In]])
+        opProcessor.asInstanceOf[Publisher[Out]]
+      }
+    val sinkValue = sink.attach(p, this)
+    new MaterializedFlow(source, sourceValue, sink, sinkValue)
   }
 
+  override def identityProcessor[I](flowName: String): Processor[I, I] =
+    processorForNode(identityTransform, flowName, 1).asInstanceOf[Processor[I, I]]
+
   private val identityTransform = Transform("identity", () ⇒
     new Transformer[Any, Any] {
       override def onNext(element: Any) = List(element)
     })
 
-  def processorForNode(op: AstNode, flowName: String, n: Int): Processor[Any, Any] = {
+  private def processorForNode(op: AstNode, flowName: String, n: Int): Processor[Any, Any] = {
     val impl = actorOf(ActorProcessorFactory.props(settings, op), s"$flowName-$n-${op.name}")
     ActorProcessorFactory(impl)
   }
 
-  def actorOf(props: Props, name: String): ActorRef = supervisor match {
+  private def actorOf(props: Props, name: String): ActorRef = supervisor match {
     case ref: LocalActorRef ⇒
       ref.underlying.attachChild(props, name, systemService = false)
     case ref: RepointableActorRef ⇒
@@ -115,6 +110,9 @@ private[akka] case class ActorBasedFlowMaterializer(
       throw new IllegalStateException(s"Stream supervisor must be a local actor, was [${supervisor.getClass.getName}]")
   }
 
+  def actorPublisher[I](props: Props, name: String, equalityValue: Option[AnyRef]): Publisher[I] =
+    ActorPublisher[I](actorOf(props, name), equalityValue)
+
 }
 
 /**
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl2/Flow.scala b/akka-stream/src/main/scala/akka/stream/scaladsl2/Flow.scala
index e6e4a90208..27a6c9b05e 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl2/Flow.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl2/Flow.scala
@@ -11,116 +11,190 @@ import org.reactivestreams.Subscriber
 import akka.stream.Transformer
 import akka.stream.impl.BlackholeSubscriber
 import akka.stream.impl2.Ast._
+import scala.annotation.unchecked.uncheckedVariance
+import akka.stream.impl.BlackholeSubscriber
+import scala.concurrent.Promise
+import akka.stream.impl.EmptyPublisher
+import akka.stream.impl.IterablePublisher
+import akka.stream.impl2.ActorBasedFlowMaterializer
 
 sealed trait Flow
 
 object FlowFrom {
   /**
-   * Helper to create `Flow` without [[Input]].
+   * Helper to create `Flow` without [[Source]].
    * Example usage: `FlowFrom[Int]`
    */
   def apply[T]: ProcessorFlow[T, T] = ProcessorFlow[T, T](Nil)
 
   /**
-   * Helper to create `Flow` with Input from `Iterable`.
+   * Helper to create `Flow` with [[Source]] from `Iterable`.
    * Example usage: `FlowFrom(Seq(1,2,3))`
    */
-  def apply[T](i: immutable.Iterable[T]): PublisherFlow[T, T] = FlowFrom[T].withInput(IterableIn(i))
+  def apply[T](i: immutable.Iterable[T]): FlowWithSource[T, T] = FlowFrom[T].withSource(IterableSource(i))
 
   /**
-   * Helper to create `Flow` with [[Input]] from `Publisher`.
+   * Helper to create `Flow` with [[Source]] from `Publisher`.
    */
-  def apply[T](p: Publisher[T]): PublisherFlow[T, T] = FlowFrom[T].withInput(PublisherIn(p))
+  def apply[T](p: Publisher[T]): FlowWithSource[T, T] = FlowFrom[T].withSource(PublisherSource(p))
 }
 
-trait Input[-In]
+trait Source[-In] {
+  def materialize(materializer: FlowMaterializer, flowName: String): (Publisher[In], AnyRef) @uncheckedVariance
+}
 
 /**
  * Default input.
  * Allows to materialize a Flow with this input to Subscriber.
  */
-final case class SubscriberIn[-In]() extends Input[In] {
-  def subscriber[I <: In]: Subscriber[I] = ???
+final case class SubscriberSource[In]() extends Source[In] {
+  override def materialize(materializer: FlowMaterializer, flowName: String): (Publisher[In], AnyRef) = {
+    val identityProcessor = materializer.identityProcessor[In](flowName)
+    (identityProcessor.asInstanceOf[Publisher[In]], identityProcessor.asInstanceOf[Subscriber[In]])
+  }
+
+  def subscriber[I <: In](m: MaterializedSource): Subscriber[I] =
+    m.getSourceFor(this).asInstanceOf[Subscriber[I]]
 }
 
 /**
- * Input from Publisher.
+ * [[Source]] from `Publisher`.
  */
-final case class PublisherIn[-In](p: Publisher[_ >: In]) extends Input[In]
+final case class PublisherSource[In](p: Publisher[_ >: In]) extends Source[In] {
+  override def materialize(materializer: FlowMaterializer, flowName: String): (Publisher[In], AnyRef) =
+    (p.asInstanceOf[Publisher[In]], p)
+}
 
 /**
- * Input from Iterable
+ * [[Source]] from `Iterable`
  *
  * Changing In from Contravariant to Covariant is needed because Iterable[+A].
- * But this brakes IterableIn variance and we get IterableIn(Seq(1,2,3)): IterableIn[Any]
+ * But this brakes IterableSource variance and we get IterableSource(Seq(1,2,3)): IterableSource[Any]
  */
-final case class IterableIn[-In](i: immutable.Iterable[_ >: In]) extends Input[In]
+final case class IterableSource[In](iterable: immutable.Iterable[_ >: In]) extends Source[In] {
+  override def materialize(materializer: FlowMaterializer, flowName: String): (Publisher[In], AnyRef) = {
+    val p =
+      if (iterable.isEmpty) EmptyPublisher.asInstanceOf[Publisher[In]]
+      else materializer match {
+        case m: ActorBasedFlowMaterializer ⇒
+          m.actorPublisher(IterablePublisher.props(iterable, materializer.settings),
+            name = s"$flowName-0-iterable", Some(iterable))
+        case other ⇒
+          throw new IllegalArgumentException(s"IterableSource requires ActorBasedFlowMaterializer, got [${other.getClass.getName}]")
+      }
+    (p.asInstanceOf[Publisher[In]], iterable)
+  }
+}
 
 /**
- * Input from Future
+ * [[Source]] from `Future`
  *
  * Changing In from Contravariant to Covariant is needed because Future[+A].
- * But this brakes FutureIn variance and we get FutureIn(Future{1}): FutureIn[Any]
+ * But this brakes FutureSource variance and we get FutureSource(Future{1}): FutureSource[Any]
  */
-final case class FutureIn[-In](f: Future[_ >: In]) extends Input[In]
+final case class FutureSource[In](f: Future[_ >: In]) extends Source[In] {
+  override def materialize(materializer: FlowMaterializer, flowName: String): (Publisher[In], AnyRef) = ???
+}
 
-trait Output[+Out]
+trait Sink[+Out] {
+  def attach(flowPublisher: Publisher[Out] @uncheckedVariance, materializer: FlowMaterializer): AnyRef
+}
 
 /**
  * Default output.
  * Allows to materialize a Flow with this output to Publisher.
  */
-final case class PublisherOut[+Out]() extends Output[Out] {
-  def publisher[O >: Out]: Publisher[O] = ???
+final case class PublisherSink[+Out]() extends Sink[Out] {
+  def attach(flowPublisher: Publisher[Out] @uncheckedVariance, materializer: FlowMaterializer): AnyRef = flowPublisher
+  def publisher[O >: Out](m: MaterializedSink): Publisher[O] = m.getSinkFor(this).asInstanceOf[Publisher[O]]
 }
 
-final case class BlackholeOut[+Out]() extends Output[Out] {
-  def publisher[O >: Out]: Publisher[O] = ???
+final case class BlackholeSink[+Out]() extends Sink[Out] {
+  override def attach(flowPublisher: Publisher[Out] @uncheckedVariance, materializer: FlowMaterializer): AnyRef = {
+    val s = new BlackholeSubscriber[Out](materializer.settings.maxInputBufferSize)
+    flowPublisher.subscribe(s)
+    s
+  }
 }
 
 /**
- * Output to a Subscriber.
+ * [[Sink]] to a Subscriber.
  */
-final case class SubscriberOut[+Out](s: Subscriber[_ <: Out]) extends Output[Out]
+final case class SubscriberSink[+Out](subscriber: Subscriber[_ <: Out]) extends Sink[Out] {
+  override def attach(flowPublisher: Publisher[Out] @uncheckedVariance, materializer: FlowMaterializer): AnyRef = {
+    flowPublisher.subscribe(subscriber.asInstanceOf[Subscriber[Out]])
+    subscriber
+  }
+}
+
+/**
+ * INTERNAL API
+ */
+private[akka] object ForeachSink {
+  private val ListOfUnit = List(())
+}
+
+/**
+ * Foreach output. Invokes the given function for each element. Completes the [[#future]] when
+ * all elements processed, or stream failed.
+ */
+final case class ForeachSink[Out](f: Out ⇒ Unit) extends Sink[Out] { // FIXME variance?
+  override def attach(flowPublisher: Publisher[Out] @uncheckedVariance, materializer: FlowMaterializer): AnyRef = {
+    val promise = Promise[Unit]()
+    FlowFrom(flowPublisher).transform("foreach", () ⇒ new Transformer[Out, Unit] {
+      override def onNext(in: Out) = { f(in); Nil }
+      override def onTermination(e: Option[Throwable]) = {
+        e match {
+          case None    ⇒ promise.success(())
+          case Some(e) ⇒ promise.failure(e)
+        }
+        Nil
+      }
+    }).consume()(materializer)
+    promise.future
+  }
+  def future(m: MaterializedSink): Future[Unit] = m.getSinkFor(this).asInstanceOf[Future[Unit]]
+}
 
 /**
  * Fold output. Reduces output stream according to the given fold function.
  */
-final case class FoldOut[T, +Out](zero: T)(f: (T, Out) ⇒ T) extends Output[Out] {
+final case class FoldSink[T, +Out](zero: T)(f: (T, Out) ⇒ T) extends Sink[Out] {
+  override def attach(flowPublisher: Publisher[Out] @uncheckedVariance, materializer: FlowMaterializer): AnyRef = ???
   def future: Future[T] = ???
 }
 
 /**
- * Operations with a Flow which has open (no attached) Input.
+ * Operations with a Flow which has no attached [[Source]].
  *
  * No Out type parameter would be useful for Graph signatures, but we need it here
- * for `withInput` and `prependTransform` methods.
+ * for `withSource` and `prependTransform` methods.
  */
-sealed trait HasOpenInput[-In, +Out] extends Flow {
-  type Repr[-In, +Out] <: HasOpenInput[In, Out]
-  type AfterCloseInput[-In, +Out] <: Flow
+sealed trait HasNoSource[-In, +Out] extends Flow {
+  type Repr[-In, +Out] <: HasNoSource[In, Out]
+  type AfterAttachingSource[-In, +Out] <: Flow
 
-  def withInput[I <: In](in: Input[I]): AfterCloseInput[I, Out]
+  def withSource[I <: In](in: Source[I]): AfterAttachingSource[I, Out]
 
   def prepend[T](f: ProcessorFlow[T, In]): Repr[T, Out]
-  def prepend[T](f: PublisherFlow[T, In]): Repr[T, Out]#AfterCloseInput[T, Out]
+  def prepend[T](f: FlowWithSource[T, In]): Repr[T, Out]#AfterAttachingSource[T, Out]
 
 }
 
 /**
- * Operations with a Flow which has open (no attached) Output.
+ * Operations with a Flow which has no attached [[Sink]].
  *
  * No In type parameter would be useful for Graph signatures, but we need it here
- * for `withOutput`.
+ * for `withSink`.
  */
-trait HasOpenOutput[-In, +Out] extends Flow {
-  type Repr[-In, +Out] <: HasOpenOutput[In, Out]
-  type AfterCloseOutput[-In, +Out] <: Flow
+trait HasNoSink[-In, +Out] extends Flow {
+  type Repr[-In, +Out] <: HasNoSink[In, Out]
+  type AfterAttachingSink[-In, +Out] <: Flow
 
   // Storing ops in reverse order
   protected def andThen[U](op: AstNode): Repr[In, U]
 
-  def withOutput[O >: Out](out: Output[O]): AfterCloseOutput[In, O]
+  def withSink[O >: Out](out: Sink[O]): AfterAttachingSink[In, O]
 
   def map[T](f: Out ⇒ T): Repr[In, T] =
     transform("map", () ⇒ new Transformer[Out, T] {
@@ -132,87 +206,110 @@ trait HasOpenOutput[-In, +Out] extends Flow {
   }
 
   def append[T](f: ProcessorFlow[Out, T]): Repr[In, T]
-  def append[T](f: SubscriberFlow[Out, T]): Repr[In, T]#AfterCloseOutput[In, T]
+  def append[T](f: FlowWithSink[Out, T]): Repr[In, T]#AfterAttachingSink[In, T]
+
 }
 
 /**
  * Flow without attached input and without attached output, can be used as a `Processor`.
  */
-final case class ProcessorFlow[-In, +Out](ops: List[AstNode]) extends HasOpenOutput[In, Out] with HasOpenInput[In, Out] {
+final case class ProcessorFlow[-In, +Out](ops: List[AstNode]) extends HasNoSink[In, Out] with HasNoSource[In, Out] {
   override type Repr[-In, +Out] = ProcessorFlow[In, Out]
-  type AfterCloseOutput[-In, +Out] = SubscriberFlow[In, Out]
-  type AfterCloseInput[-In, +Out] = PublisherFlow[In, Out]
+  type AfterAttachingSink[-In, +Out] = FlowWithSink[In, Out]
+  type AfterAttachingSource[-In, +Out] = FlowWithSource[In, Out]
 
   override protected def andThen[U](op: AstNode): Repr[In, U] = this.copy(ops = op :: ops)
 
-  def withOutput[O >: Out](out: Output[O]): AfterCloseOutput[In, O] = SubscriberFlow(out, ops)
-  def withInput[I <: In](in: Input[I]): AfterCloseInput[I, Out] = PublisherFlow(in, ops)
+  override def withSink[O >: Out](out: Sink[O]): AfterAttachingSink[In, O] = FlowWithSink(out, ops)
+  override def withSource[I <: In](in: Source[I]): AfterAttachingSource[I, Out] = FlowWithSource(in, ops)
 
   override def prepend[T](f: ProcessorFlow[T, In]): Repr[T, Out] =
     ProcessorFlow(ops ::: f.ops)
-  override def prepend[T](f: PublisherFlow[T, In]): Repr[T, Out]#AfterCloseInput[T, Out] =
-    PublisherFlow(f.input, ops ::: f.ops)
+  override def prepend[T](f: FlowWithSource[T, In]): Repr[T, Out]#AfterAttachingSource[T, Out] =
+    FlowWithSource(f.input, ops ::: f.ops)
 
   override def append[T](f: ProcessorFlow[Out, T]): Repr[In, T] = ProcessorFlow(f.ops ++: ops)
-  override def append[T](f: SubscriberFlow[Out, T]): Repr[In, T]#AfterCloseOutput[In, T] =
-    SubscriberFlow(f.output, f.ops ++: ops)
+  override def append[T](f: FlowWithSink[Out, T]): Repr[In, T]#AfterAttachingSink[In, T] =
+    FlowWithSink(f.output, f.ops ++: ops)
 }
 
 /**
  *  Flow with attached output, can be used as a `Subscriber`.
  */
-final case class SubscriberFlow[-In, +Out](output: Output[Out], ops: List[AstNode]) extends HasOpenInput[In, Out] {
-  type Repr[-In, +Out] = SubscriberFlow[In, Out]
-  type AfterCloseInput[-In, +Out] = RunnableFlow[In, Out]
+final case class FlowWithSink[-In, +Out](output: Sink[Out], ops: List[AstNode]) extends HasNoSource[In, Out] {
+  type Repr[-In, +Out] = FlowWithSink[In, Out]
+  type AfterAttachingSource[-In, +Out] = RunnableFlow[In, Out]
 
-  def withInput[I <: In](in: Input[I]): AfterCloseInput[I, Out] = RunnableFlow(in, output, ops)
-  def withoutOutput: ProcessorFlow[In, Out] = ProcessorFlow(ops)
+  override def withSource[I <: In](in: Source[I]): AfterAttachingSource[I, Out] = RunnableFlow(in, output, ops)
+  def withoutSink: ProcessorFlow[In, Out] = ProcessorFlow(ops)
 
   override def prepend[T](f: ProcessorFlow[T, In]): Repr[T, Out] =
-    SubscriberFlow(output, ops ::: f.ops)
-  override def prepend[T](f: PublisherFlow[T, In]): Repr[T, Out]#AfterCloseInput[T, Out] =
+    FlowWithSink(output, ops ::: f.ops)
+  override def prepend[T](f: FlowWithSource[T, In]): Repr[T, Out]#AfterAttachingSource[T, Out] =
     RunnableFlow(f.input, output, ops ::: f.ops)
+
+  def toSubscriber[I <: In]()(implicit materializer: FlowMaterializer): Subscriber[I] = {
+    val subIn = SubscriberSource[I]()
+    val mf = withSource(subIn).run()
+    subIn.subscriber(mf)
+  }
 }
 
 /**
  * Flow with attached input, can be used as a `Publisher`.
  */
-final case class PublisherFlow[-In, +Out](input: Input[In], ops: List[AstNode]) extends HasOpenOutput[In, Out] {
-  override type Repr[-In, +Out] = PublisherFlow[In, Out]
-  type AfterCloseOutput[-In, +Out] = RunnableFlow[In, Out]
+final case class FlowWithSource[-In, +Out](input: Source[In], ops: List[AstNode]) extends HasNoSink[In, Out] {
+  override type Repr[-In, +Out] = FlowWithSource[In, Out]
+  type AfterAttachingSink[-In, +Out] = RunnableFlow[In, Out]
 
   override protected def andThen[U](op: AstNode): Repr[In, U] = this.copy(ops = op :: ops)
 
-  def withOutput[O >: Out](out: Output[O]): AfterCloseOutput[In, O] = RunnableFlow(input, out, ops)
-  def withoutInput: ProcessorFlow[In, Out] = ProcessorFlow(ops)
+  override def withSink[O >: Out](out: Sink[O]): AfterAttachingSink[In, O] = RunnableFlow(input, out, ops)
+  def withoutSource: ProcessorFlow[In, Out] = ProcessorFlow(ops)
 
-  override def append[T](f: ProcessorFlow[Out, T]): Repr[In, T] = PublisherFlow(input, f.ops ++: ops)
-  override def append[T](f: SubscriberFlow[Out, T]): Repr[In, T]#AfterCloseOutput[In, T] =
+  override def append[T](f: ProcessorFlow[Out, T]): Repr[In, T] = FlowWithSource(input, f.ops ++: ops)
+  override def append[T](f: FlowWithSink[Out, T]): Repr[In, T]#AfterAttachingSink[In, T] =
     RunnableFlow(input, f.output, f.ops ++: ops)
 
+  def toPublisher[U >: Out]()(implicit materializer: FlowMaterializer): Publisher[U] = {
+    val pubOut = PublisherSink[Out]()
+    val mf = withSink(pubOut).run()
+    pubOut.publisher(mf)
+  }
+
+  def publishTo(subscriber: Subscriber[_ >: Out])(implicit materializer: FlowMaterializer): Unit =
+    toPublisher().subscribe(subscriber.asInstanceOf[Subscriber[Out]])
+
+  def consume()(implicit materializer: FlowMaterializer): Unit =
+    withSink(BlackholeSink()).run()
+
 }
 
 /**
  * Flow with attached input and output, can be executed.
  */
-final case class RunnableFlow[-In, +Out](input: Input[In], output: Output[Out], ops: List[AstNode]) extends Flow {
-  def withoutOutput: PublisherFlow[In, Out] = PublisherFlow(input, ops)
-  def withoutInput: SubscriberFlow[In, Out] = SubscriberFlow(output, ops)
-
-  // FIXME
-  def run()(implicit materializer: FlowMaterializer): Unit =
-    produceTo(new BlackholeSubscriber[Any](materializer.settings.maxInputBufferSize))
-
-  // FIXME replace with run and input/output factories
-  def toPublisher[U >: Out]()(implicit materializer: FlowMaterializer): Publisher[U] =
-    input match {
-      case PublisherIn(p)   ⇒ materializer.toPublisher(ExistingPublisher(p), ops)
-      case IterableIn(iter) ⇒ materializer.toPublisher(IterablePublisherNode(iter), ops)
-      case _                ⇒ ???
-    }
-
-  def produceTo(subscriber: Subscriber[_ >: Out])(implicit materializer: FlowMaterializer): Unit =
-    toPublisher().subscribe(subscriber.asInstanceOf[Subscriber[Out]])
+final case class RunnableFlow[-In, +Out](input: Source[In], output: Sink[Out], ops: List[AstNode]) extends Flow {
+  def withoutSink: FlowWithSource[In, Out] = FlowWithSource(input, ops)
+  def withoutSource: FlowWithSink[In, Out] = FlowWithSink(output, ops)
 
+  def run()(implicit materializer: FlowMaterializer): MaterializedFlow =
+    materializer.materialize(input, output, ops)
 }
 
+class MaterializedFlow(sourceKey: AnyRef, matSource: AnyRef, sinkKey: AnyRef, matSink: AnyRef) extends MaterializedSource with MaterializedSink {
+  override def getSourceFor(key: AnyRef): AnyRef =
+    if (key == sourceKey) matSource
+    else throw new IllegalArgumentException(s"Source key [$key] doesn't match the source [$sourceKey] of this flow")
+
+  def getSinkFor(key: AnyRef): AnyRef =
+    if (key == sinkKey) matSink
+    else throw new IllegalArgumentException(s"Sink key [$key] doesn't match the sink [$sinkKey] of this flow")
+}
+
+trait MaterializedSource {
+  def getSourceFor(sourceKey: AnyRef): AnyRef
+}
+
+trait MaterializedSink {
+  def getSinkFor(sinkKey: AnyRef): AnyRef
+}
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl2/FlowMaterializer.scala b/akka-stream/src/main/scala/akka/stream/scaladsl2/FlowMaterializer.scala
index 8bb91e81d5..9f97c947b9 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl2/FlowMaterializer.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl2/FlowMaterializer.scala
@@ -15,6 +15,7 @@ import akka.actor.ActorContext
 import akka.stream.impl2.StreamSupervisor
 import akka.stream.impl2.FlowNameCounter
 import akka.stream.MaterializerSettings
+import org.reactivestreams.Processor
 
 object FlowMaterializer {
 
@@ -22,8 +23,7 @@ object FlowMaterializer {
    * Scala API: Creates a FlowMaterializer which will execute every step of a transformation
    * pipeline within its own [[akka.actor.Actor]]. The required [[akka.actor.ActorRefFactory]]
    * (which can be either an [[akka.actor.ActorSystem]] or an [[akka.actor.ActorContext]])
-   * will be used to create these actors, therefore it is *forbidden* to pass this object
-   * to another actor if the factory is an ActorContext.
+   * will be used to create one actor that in turn creates actors for the transformation steps.
    *
    * The `namePrefix` is used as the first part of the names of the actors running
    * the processing steps. The default `namePrefix` is `"flow"`. The actor names are built up of
@@ -49,8 +49,7 @@ object FlowMaterializer {
    * Java API: Creates a FlowMaterializer which will execute every step of a transformation
    * pipeline within its own [[akka.actor.Actor]]. The required [[akka.actor.ActorRefFactory]]
    * (which can be either an [[akka.actor.ActorSystem]] or an [[akka.actor.ActorContext]])
-   * will be used to create these actors, therefore it is *forbidden* to pass this object
-   * to another actor if the factory is an ActorContext.
+   * will be used to create one actor that in turn creates actors for the transformation steps.
    */
   def create(settings: MaterializerSettings, context: ActorRefFactory): FlowMaterializer =
     apply(settings)(context)
@@ -75,7 +74,12 @@ abstract class FlowMaterializer(val settings: MaterializerSettings) {
    * INTERNAL API
    * ops are stored in reverse order
    */
-  private[akka] def toPublisher[I, O](publisherNode: Ast.PublisherNode[I], ops: List[Ast.AstNode]): Publisher[O]
+  private[akka] def materialize[In, Out](source: Source[In], sink: Sink[Out], ops: List[Ast.AstNode]): MaterializedFlow
+
+  /**
+   * INTERNAL API
+   */
+  private[akka] def identityProcessor[I](flowName: String): Processor[I, I]
 
 }
 
diff --git a/akka-stream/src/test/scala/akka/stream/FlowGroupBySpec.scala b/akka-stream/src/test/scala/akka/stream/FlowGroupBySpec.scala
index 399f402cc9..a7306a2127 100644
--- a/akka-stream/src/test/scala/akka/stream/FlowGroupBySpec.scala
+++ b/akka-stream/src/test/scala/akka/stream/FlowGroupBySpec.scala
@@ -1,5 +1,5 @@
 /**
- * Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
+ * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
  */
 package akka.stream
 
diff --git a/akka-stream/src/test/scala/akka/stream/FlowMergeSpec.scala b/akka-stream/src/test/scala/akka/stream/FlowMergeSpec.scala
index 5f59df319f..6d5a747d09 100644
--- a/akka-stream/src/test/scala/akka/stream/FlowMergeSpec.scala
+++ b/akka-stream/src/test/scala/akka/stream/FlowMergeSpec.scala
@@ -1,5 +1,5 @@
 /**
- * Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
+ * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
  */
 package akka.stream
 
diff --git a/akka-stream/src/test/scala/akka/stream/FlowSplitWhenSpec.scala b/akka-stream/src/test/scala/akka/stream/FlowSplitWhenSpec.scala
index a89b199edb..98044f7002 100644
--- a/akka-stream/src/test/scala/akka/stream/FlowSplitWhenSpec.scala
+++ b/akka-stream/src/test/scala/akka/stream/FlowSplitWhenSpec.scala
@@ -1,5 +1,5 @@
 /**
- * Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
+ * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
  */
 package akka.stream
 
diff --git a/akka-stream/src/test/scala/akka/stream/scaladsl2/FlowSpec.scala b/akka-stream/src/test/scala/akka/stream/scaladsl2/FlowSpec.scala
index ec261a4a6a..41460212e7 100644
--- a/akka-stream/src/test/scala/akka/stream/scaladsl2/FlowSpec.scala
+++ b/akka-stream/src/test/scala/akka/stream/scaladsl2/FlowSpec.scala
@@ -11,30 +11,30 @@ import scala.concurrent.Future
 
 class FlowSpec extends AkkaSpec {
 
-  val intSeq = IterableIn(Seq(1, 2, 3))
-  val strSeq = IterableIn(Seq("a", "b", "c"))
+  val intSeq = IterableSource(Seq(1, 2, 3))
+  val strSeq = IterableSource(Seq("a", "b", "c"))
 
   import scala.concurrent.ExecutionContext.Implicits.global
-  val intFut = FutureIn(Future { 3 })
+  val intFut = FutureSource(Future { 3 })
   implicit val materializer = FlowMaterializer(MaterializerSettings(system))
 
   "ProcessorFlow" should {
     "go through all states" in {
       val f: ProcessorFlow[Int, Int] = FlowFrom[Int]
-        .withInput(intSeq)
-        .withOutput(PublisherOut())
-        .withoutInput
-        .withoutOutput
+        .withSource(intSeq)
+        .withSink(PublisherSink())
+        .withoutSource
+        .withoutSink
     }
     "should not run" in {
       val open: ProcessorFlow[Int, Int] = FlowFrom[Int]
       "open.run()" shouldNot compile
     }
-    "accept IterableIn" in {
-      val f: PublisherFlow[Int, Int] = FlowFrom[Int].withInput(intSeq)
+    "accept IterableSource" in {
+      val f: FlowWithSource[Int, Int] = FlowFrom[Int].withSource(intSeq)
     }
-    "accept FutureIn" in {
-      val f: PublisherFlow[Int, Int] = FlowFrom[Int].withInput(intFut)
+    "accept FutureSource" in {
+      val f: FlowWithSource[Int, Int] = FlowFrom[Int].withSource(intFut)
     }
     "append ProcessorFlow" in {
       val open1: ProcessorFlow[Int, String] = FlowFrom[Int].map(_.toString)
@@ -42,14 +42,14 @@ class FlowSpec extends AkkaSpec {
       val open3: ProcessorFlow[Int, Int] = open1.append(open2)
       "open3.run()" shouldNot compile
 
-      val closedInput: PublisherFlow[Int, Int] = open3.withInput(intSeq)
-      "closedInput.run()" shouldNot compile
+      val closedSource: FlowWithSource[Int, Int] = open3.withSource(intSeq)
+      "closedSource.run()" shouldNot compile
 
-      val closedOutput: SubscriberFlow[Int, Int] = open3.withOutput(PublisherOut())
-      "closedOutput.run()" shouldNot compile
+      val closedSink: FlowWithSink[Int, Int] = open3.withSink(PublisherSink())
+      "closedSink.run()" shouldNot compile
 
-      closedInput.withOutput(PublisherOut()).run()
-      closedOutput.withInput(intSeq).run()
+      closedSource.withSink(PublisherSink()).run()
+      closedSink.withSource(intSeq).run()
     }
     "prepend ProcessorFlow" in {
       val open1: ProcessorFlow[Int, String] = FlowFrom[Int].map(_.toString)
@@ -57,89 +57,89 @@ class FlowSpec extends AkkaSpec {
       val open3: ProcessorFlow[String, String] = open1.prepend(open2)
       "open3.run()" shouldNot compile
 
-      val closedInput: PublisherFlow[String, String] = open3.withInput(strSeq)
-      "closedInput.run()" shouldNot compile
+      val closedSource: FlowWithSource[String, String] = open3.withSource(strSeq)
+      "closedSource.run()" shouldNot compile
 
-      val closedOutput: SubscriberFlow[String, String] = open3.withOutput(PublisherOut())
-      "closedOutput.run()" shouldNot compile
+      val closedSink: FlowWithSink[String, String] = open3.withSink(PublisherSink())
+      "closedSink.run()" shouldNot compile
 
-      closedInput.withOutput(PublisherOut()).run
-      closedOutput.withInput(strSeq).run
+      closedSource.withSink(PublisherSink()).run
+      closedSink.withSource(strSeq).run
     }
-    "append SubscriberFlow" in {
+    "append FlowWithSink" in {
       val open: ProcessorFlow[Int, String] = FlowFrom[Int].map(_.toString)
-      val closedOutput: SubscriberFlow[String, Int] = FlowFrom[String].map(_.hashCode).withOutput(PublisherOut())
-      val appended: SubscriberFlow[Int, Int] = open.append(closedOutput)
+      val closedSink: FlowWithSink[String, Int] = FlowFrom[String].map(_.hashCode).withSink(PublisherSink())
+      val appended: FlowWithSink[Int, Int] = open.append(closedSink)
       "appended.run()" shouldNot compile
       "appended.toFuture" shouldNot compile
-      appended.withInput(intSeq).run
+      appended.withSource(intSeq).run
     }
-    "prepend PublisherFlow" in {
+    "prepend FlowWithSource" in {
       val open: ProcessorFlow[Int, String] = FlowFrom[Int].map(_.toString)
-      val closedInput: PublisherFlow[String, Int] = FlowFrom[String].map(_.hashCode).withInput(strSeq)
-      val prepended: PublisherFlow[String, String] = open.prepend(closedInput)
+      val closedSource: FlowWithSource[String, Int] = FlowFrom[String].map(_.hashCode).withSource(strSeq)
+      val prepended: FlowWithSource[String, String] = open.prepend(closedSource)
       "prepended.run()" shouldNot compile
-      "prepended.withInput(strSeq)" shouldNot compile
-      prepended.withOutput(PublisherOut()).run
+      "prepended.withSource(strSeq)" shouldNot compile
+      prepended.withSink(PublisherSink()).run
     }
   }
 
-  "SubscriberFlow" should {
-    val openInput: SubscriberFlow[Int, String] =
-      FlowFrom[Int].map(_.toString).withOutput(PublisherOut())
-    "accept Input" in {
-      openInput.withInput(intSeq)
+  "FlowWithSink" should {
+    val openSource: FlowWithSink[Int, String] =
+      FlowFrom[Int].map(_.toString).withSink(PublisherSink())
+    "accept Source" in {
+      openSource.withSource(intSeq)
     }
-    "drop Output" in {
-      openInput.withoutOutput
+    "drop Sink" in {
+      openSource.withoutSink
     }
-    "not drop Input" in {
-      "openInput.withoutInput" shouldNot compile
+    "not drop Source" in {
+      "openSource.withoutSource" shouldNot compile
     }
-    "not accept Output" in {
-      "openInput.ToFuture" shouldNot compile
+    "not accept Sink" in {
+      "openSource.ToFuture" shouldNot compile
     }
     "not run()" in {
-      "openInput.run()" shouldNot compile
+      "openSource.run()" shouldNot compile
     }
   }
 
-  "PublisherFlow" should {
-    val openOutput: PublisherFlow[Int, String] =
+  "FlowWithSource" should {
+    val openSink: FlowWithSource[Int, String] =
       FlowFrom(Seq(1, 2, 3)).map(_.toString)
-    "accept Output" in {
-      openOutput.withOutput(PublisherOut())
+    "accept Sink" in {
+      openSink.withSink(PublisherSink())
     }
-    "drop Input" in {
-      openOutput.withoutInput
+    "drop Source" in {
+      openSink.withoutSource
     }
-    "not drop Output" in {
-      "openOutput.withoutOutput" shouldNot compile
+    "not drop Sink" in {
+      "openSink.withoutSink" shouldNot compile
     }
-    "not accept Input" in {
-      "openOutput.withInput(intSeq)" shouldNot compile
+    "not accept Source" in {
+      "openSink.withSource(intSeq)" shouldNot compile
     }
     "not run()" in {
-      "openOutput.run()" shouldNot compile
+      "openSink.run()" shouldNot compile
     }
   }
 
   "RunnableFlow" should {
     val closed: RunnableFlow[Int, String] =
-      FlowFrom(Seq(1, 2, 3)).map(_.toString).withOutput(PublisherOut())
+      FlowFrom(Seq(1, 2, 3)).map(_.toString).withSink(PublisherSink())
     "run" in {
       closed.run()
     }
-    "drop Input" in {
-      closed.withoutInput
+    "drop Source" in {
+      closed.withoutSource
     }
-    "drop Output" in {
-      closed.withoutOutput
+    "drop Sink" in {
+      closed.withoutSink
     }
-    "not accept Input" in {
-      "closed.withInput(intSeq)" shouldNot compile
+    "not accept Source" in {
+      "closed.withSource(intSeq)" shouldNot compile
     }
-    "not accept Output" in {
+    "not accept Sink" in {
       "closed.ToFuture" shouldNot compile
     }
   }
diff --git a/akka-stream/src/test/scala/akka/stream/scaladsl2/FlowTransformSpec.scala b/akka-stream/src/test/scala/akka/stream/scaladsl2/FlowTransformSpec.scala
index fb25ddb227..023c76ebe9 100644
--- a/akka-stream/src/test/scala/akka/stream/scaladsl2/FlowTransformSpec.scala
+++ b/akka-stream/src/test/scala/akka/stream/scaladsl2/FlowTransformSpec.scala
@@ -23,7 +23,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
 
   "A Flow with transform operations" must {
     "produce one-to-one transformation as expected" in {
-      val p = FlowFrom(List(1, 2, 3)).withOutput(PublisherOut()).toPublisher()
+      val p = FlowFrom(List(1, 2, 3)).toPublisher()
       val p2 = FlowFrom(p).
         transform("transform", () ⇒ new Transformer[Int, Int] {
           var tot = 0
@@ -32,7 +32,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
             List(tot)
           }
         }).
-        withOutput(PublisherOut()).toPublisher()
+        toPublisher()
       val subscriber = StreamTestKit.SubscriberProbe[Int]()
       p2.subscribe(subscriber)
       val subscription = subscriber.expectSubscription()
@@ -46,7 +46,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
     }
 
     "produce one-to-several transformation as expected" in {
-      val p = FlowFrom(List(1, 2, 3)).withOutput(PublisherOut()).toPublisher()
+      val p = FlowFrom(List(1, 2, 3)).toPublisher()
       val p2 = FlowFrom(p).
         transform("transform", () ⇒ new Transformer[Int, Int] {
           var tot = 0
@@ -55,7 +55,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
             Vector.fill(elem)(tot)
           }
         }).
-        withOutput(PublisherOut()).toPublisher()
+        toPublisher()
       val subscriber = StreamTestKit.SubscriberProbe[Int]()
       p2.subscribe(subscriber)
       val subscription = subscriber.expectSubscription()
@@ -72,7 +72,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
     }
 
     "produce dropping transformation as expected" in {
-      val p = FlowFrom(List(1, 2, 3, 4)).withOutput(PublisherOut()).toPublisher()
+      val p = FlowFrom(List(1, 2, 3, 4)).toPublisher()
       val p2 = FlowFrom(p).
         transform("transform", () ⇒ new Transformer[Int, Int] {
           var tot = 0
@@ -85,7 +85,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
             }
           }
         }).
-        withOutput(PublisherOut()).toPublisher()
+        toPublisher()
       val subscriber = StreamTestKit.SubscriberProbe[Int]()
       p2.subscribe(subscriber)
       val subscription = subscriber.expectSubscription()
@@ -99,7 +99,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
     }
 
     "produce multi-step transformation as expected" in {
-      val p = FlowFrom(List("a", "bc", "def")).withOutput(PublisherOut()).toPublisher()
+      val p = FlowFrom(List("a", "bc", "def")).toPublisher()
       val p2 = FlowFrom(p).
         transform("transform", () ⇒ new Transformer[String, Int] {
           var concat = ""
@@ -115,7 +115,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
             List(tot)
           }
         }).
-        withOutput(PublisherOut()).toPublisher()
+        toPublisher()
       val c1 = StreamTestKit.SubscriberProbe[Int]()
       p2.subscribe(c1)
       val sub1 = c1.expectSubscription()
@@ -138,7 +138,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
     }
 
     "invoke onComplete when done" in {
-      val p = FlowFrom(List("a")).withOutput(PublisherOut()).toPublisher()
+      val p = FlowFrom(List("a")).toPublisher()
       val p2 = FlowFrom(p).
         transform("transform", () ⇒ new Transformer[String, String] {
           var s = ""
@@ -148,7 +148,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
           }
           override def onTermination(e: Option[Throwable]) = List(s + "B")
         }).
-        withOutput(PublisherOut()).toPublisher()
+        toPublisher()
       val c = StreamTestKit.SubscriberProbe[String]()
       p2.subscribe(c)
       val s = c.expectSubscription()
@@ -159,7 +159,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
 
     "invoke cleanup when done" in {
       val cleanupProbe = TestProbe()
-      val p = FlowFrom(List("a")).withOutput(PublisherOut()).toPublisher()
+      val p = FlowFrom(List("a")).toPublisher()
       val p2 = FlowFrom(p).
         transform("transform", () ⇒ new Transformer[String, String] {
           var s = ""
@@ -170,7 +170,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
           override def onTermination(e: Option[Throwable]) = List(s + "B")
           override def cleanup() = cleanupProbe.ref ! s
         }).
-        withOutput(PublisherOut()).toPublisher()
+        toPublisher()
       val c = StreamTestKit.SubscriberProbe[String]()
       p2.subscribe(c)
       val s = c.expectSubscription()
@@ -182,7 +182,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
 
     "invoke cleanup when done consume" in {
       val cleanupProbe = TestProbe()
-      val p = FlowFrom(List("a")).withOutput(PublisherOut()).toPublisher()
+      val p = FlowFrom(List("a")).toPublisher()
       FlowFrom(p).
         transform("transform", () ⇒ new Transformer[String, String] {
           var s = "x"
@@ -192,13 +192,13 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
           }
           override def cleanup() = cleanupProbe.ref ! s
         }).
-        withOutput(BlackholeOut()).run()
+        withSink(BlackholeSink()).run()
       cleanupProbe.expectMsg("a")
     }
 
     "invoke cleanup when done after error" in {
       val cleanupProbe = TestProbe()
-      val p = FlowFrom(List("a", "b", "c")).withOutput(PublisherOut()).toPublisher()
+      val p = FlowFrom(List("a", "b", "c")).toPublisher()
       val p2 = FlowFrom(p).
         transform("transform", () ⇒ new Transformer[String, String] {
           var s = ""
@@ -214,7 +214,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
           override def onTermination(e: Option[Throwable]) = List(s + "B")
           override def cleanup() = cleanupProbe.ref ! s
         }).
-        withOutput(PublisherOut()).toPublisher()
+        toPublisher()
       val c = StreamTestKit.SubscriberProbe[String]()
       p2.subscribe(c)
       val s = c.expectSubscription()
@@ -236,7 +236,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
           }
           override def isComplete = s == "1"
         }).
-        withOutput(PublisherOut()).toPublisher()
+        toPublisher()
       val proc = p.expectSubscription
       val c = StreamTestKit.SubscriberProbe[Int]()
       p2.subscribe(c)
@@ -263,7 +263,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
           override def onTermination(e: Option[Throwable]) = List(s.length + 10)
           override def cleanup() = cleanupProbe.ref ! s
         }).
-        withOutput(PublisherOut()).toPublisher()
+        toPublisher()
       val proc = p.expectSubscription
       val c = StreamTestKit.SubscriberProbe[Int]()
       p2.subscribe(c)
@@ -279,7 +279,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
     }
 
     "report error when exception is thrown" in {
-      val p = FlowFrom(List(1, 2, 3)).withOutput(PublisherOut()).toPublisher()
+      val p = FlowFrom(List(1, 2, 3)).toPublisher()
       val p2 = FlowFrom(p).
         transform("transform", () ⇒ new Transformer[Int, Int] {
           override def onNext(elem: Int) = {
@@ -290,7 +290,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
             }
           }
         }).
-        withOutput(PublisherOut()).toPublisher()
+        toPublisher()
       val subscriber = StreamTestKit.SubscriberProbe[Int]()
       p2.subscribe(subscriber)
       val subscription = subscriber.expectSubscription()
@@ -304,12 +304,12 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
     }
 
     "support cancel as expected" in {
-      val p = FlowFrom(List(1, 2, 3)).withOutput(PublisherOut()).toPublisher()
+      val p = FlowFrom(List(1, 2, 3)).toPublisher()
       val p2 = FlowFrom(p).
         transform("transform", () ⇒ new Transformer[Int, Int] {
           override def onNext(elem: Int) = List(elem, elem)
         }).
-        withOutput(PublisherOut()).toPublisher()
+        toPublisher()
       val subscriber = StreamTestKit.SubscriberProbe[Int]()
       p2.subscribe(subscriber)
       val subscription = subscriber.expectSubscription()
@@ -323,13 +323,13 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
     }
 
     "support producing elements from empty inputs" in {
-      val p = FlowFrom(List.empty[Int]).withOutput(PublisherOut()).toPublisher()
+      val p = FlowFrom(List.empty[Int]).toPublisher()
       val p2 = FlowFrom(p).
         transform("transform", () ⇒ new Transformer[Int, Int] {
           override def onNext(elem: Int) = Nil
           override def onTermination(e: Option[Throwable]) = List(1, 2, 3)
         }).
-        withOutput(PublisherOut()).toPublisher()
+        toPublisher()
       val subscriber = StreamTestKit.SubscriberProbe[Int]()
       p2.subscribe(subscriber)
       val subscription = subscriber.expectSubscription()
@@ -363,7 +363,7 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
               case _ ⇒ Nil
             }
         }
-      }).withOutput(PublisherOut()).produceTo(subscriber)
+      }).publishTo(subscriber)
 
       val subscription = subscriber.expectSubscription()
       subscription.request(10)
@@ -383,16 +383,16 @@ class FlowTransformSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.d
             count += 1
             List(count)
           }
-        }).withOutput(PublisherOut())
+        })
 
       val s1 = StreamTestKit.SubscriberProbe[Int]()
-      flow.produceTo(s1)
+      flow.publishTo(s1)
       s1.expectSubscription().request(3)
       s1.expectNext(1, 2, 3)
       s1.expectComplete()
 
       val s2 = StreamTestKit.SubscriberProbe[Int]()
-      flow.produceTo(s2)
+      flow.publishTo(s2)
       s2.expectSubscription().request(3)
       s2.expectNext(1, 2, 3)
       s2.expectComplete()