+str #16965 add generalized UnzipWith

akka-docs-dev/rst/java/stream-graphs.rst

@@ -29,6 +29,7 @@ Akka Streams currently provide these junctions (for a detailed list see :ref:`st
 
  - ``Broadcast[T]`` – *(1 input, N outputs)* given an input element emits to each output
  - ``Balance[T]`` – *(1 input, N outputs)* given an input element emits to one of its output ports
+ - ``UnzipWith[In,A,B,...]`` – *(1 input, N outputs)* takes a function of 1 input that given a value for each input emits N output elements (where N <= 20)
  - ``UnZip[A,B]`` – *(1 input, 2 outputs)* splits a stream of ``(A,B)`` tuples into two streams, one of type ``A`` and one of type ``B``
  - ``FlexiRoute[In]`` – *(1 input, N outputs)* enables writing custom fan out elements using a simple DSL
 

akka-docs-dev/rst/scala/stream-graphs.rst

@@ -30,6 +30,7 @@ Akka Streams currently provide these junctions (for a detailed list see :ref:`st
 
  - ``Broadcast[T]`` – *(1 input, N outputs)* given an input element emits to each output
  - ``Balance[T]`` – *(1 input, N outputs)* given an input element emits to one of its output ports
+ - ``UnzipWith[In,A,B,...]`` – *(1 input, N outputs)* takes a function of 1 input that given a value for each input emits N output elements (where N <= 20)
  - ``UnZip[A,B]`` – *(1 input, 2 outputs)* splits a stream of ``(A,B)`` tuples into two streams, one of type ``A`` and one of type ``B``
  - ``FlexiRoute[In]`` – *(1 input, N outputs)* enables writing custom fan out elements using a simple DSL
 

akka-docs-dev/rst/stages-overview.rst

@@ -138,6 +138,7 @@ route the elements between different outputs, or emit elements on multiple outpu
 Stage                  Emits when                                                                                                                  Backpressures when                                                                                                              Completes when
 =====================  =========================================================================================================================   ==============================================================================================================================  =====================================================================================
 unzip                  all of the outputs stops backpressuring and there is an input element available                                             any of the outputs backpressures                                                                                                upstream completes
+unzipWith              all of the outputs stops backpressuring and there is an input element available                                             any of the outputs backpressures                                                                                                upstream completes
 broadcast              all of the outputs stops backpressuring and there is an input element available                                             any of the outputs backpressures                                                                                                upstream completes
 balance                any of the outputs stops backpressuring; emits the element to the first available output                                    all of the outputs backpressure                                                                                                 upstream completes
 =====================  =========================================================================================================================   ==============================================================================================================================  =====================================================================================

akka-stream-tests/src/test/java/akka/stream/javadsl/FlowGraphTest.java

@@ -4,8 +4,10 @@
 package akka.stream.javadsl;
 
 import akka.actor.ActorRef;
+import akka.dispatch.japi;
 import akka.japi.Pair;
 import akka.pattern.Patterns;
+import akka.japi.Tuple4;
 import akka.stream.*;
 import akka.stream.javadsl.FlowGraph.Builder;
 import akka.stream.stage.*;
@@ -97,13 +99,7 @@ public class FlowGraphTest extends StreamTest {
     final Source<String, BoxedUnit> in1 = Source.from(input1);
     final Source<Integer, BoxedUnit> in2 = Source.from(input2);
     final FanInShape2<String, Integer, Pair<String,Integer>> zip = b.graph(Zip.<String, Integer>create());
-    final Sink<Pair<String, Integer>, Future<BoxedUnit>> out = Sink
-      .foreach(new Procedure<Pair<String, Integer>>() {
-        @Override
-        public void apply(Pair<String, Integer> param) throws Exception {
-          probe.getRef().tell(param, ActorRef.noSender());
-        }
-      });
+    final Sink<Pair<String, Integer>, BoxedUnit> out = createSink(probe);
 
     b.edge(b.source(in1), zip.in0());
     b.edge(b.source(in2), zip.in1());
@@ -133,18 +129,8 @@ public class FlowGraphTest extends StreamTest {
     final Outlet<Pair<String, Integer>> in = b.source(Source.from(input));
     final FanOutShape2<Pair<String, Integer>, String, Integer> unzip = b.graph(Unzip.<String, Integer>create());
 
-    final Sink<String, Future<BoxedUnit>> out1 = Sink.foreach(new Procedure<String>() {
-      @Override
-      public void apply(String param) throws Exception {
-        probe1.getRef().tell(param, ActorRef.noSender());
-      }
-    });
-    final Sink<Integer, Future<BoxedUnit>> out2 = Sink.foreach(new Procedure<Integer>() {
-      @Override
-      public void apply(Integer param) throws Exception {
-        probe2.getRef().tell(param, ActorRef.noSender());
-      }
-    });
+    final Sink<String, BoxedUnit> out1 = createSink(probe1);
+    final Sink<Integer, BoxedUnit> out2 = createSink(probe2);
 
     b.edge(in, unzip.in());
     b.edge(unzip.out0(), b.sink(out1));
@@ -157,6 +143,87 @@ public class FlowGraphTest extends StreamTest {
     assertEquals(expected2, output2);
   }
 
+  private static <T> Sink<T, BoxedUnit> createSink(final JavaTestKit probe){
+    return Sink.actorRef(probe.getRef(), "onComplete");
+  }
+
+  @Test
+  public void mustBeAbleToUseUnzipWith() throws Exception {
+    final JavaTestKit probe1 = new JavaTestKit(system);
+    final JavaTestKit probe2 = new JavaTestKit(system);
+
+    final Builder<BoxedUnit> b = FlowGraph.builder();
+    final Source<Integer, BoxedUnit> in = Source.single(1);
+
+    final FanOutShape2<Integer, String, Integer> unzip = b.graph(UnzipWith.create(
+      new Function<Integer, Pair<String, Integer>>() {
+        @Override public Pair<String, Integer> apply(Integer l) throws Exception {
+          return new Pair<String, Integer>(l + "!", l);
+        }
+      })
+    );
+
+    final Sink<String, BoxedUnit> out1 = createSink(probe1);
+    final Sink<Integer, BoxedUnit> out2 = createSink(probe2);
+
+    b.edge(b.source(in), unzip.in());
+    b.edge(unzip.out0(), b.sink(out1));
+    b.edge(unzip.out1(), b.sink(out2));
+    b.run(materializer);
+
+    Duration d = Duration.create(300, TimeUnit.MILLISECONDS);
+
+    Object output1 = probe1.receiveOne(d);
+    Object output2 = probe2.receiveOne(d);
+
+    assertEquals("1!", output1);
+    assertEquals(1, output2);
+
+  }
+
+  @Test
+  public void mustBeAbleToUseUnzip4With() throws Exception {
+    final JavaTestKit probe1 = new JavaTestKit(system);
+    final JavaTestKit probe2 = new JavaTestKit(system);
+    final JavaTestKit probe3 = new JavaTestKit(system);
+    final JavaTestKit probe4 = new JavaTestKit(system);
+
+    final Builder<BoxedUnit> b = FlowGraph.builder();
+    final Source<Integer, BoxedUnit> in = Source.single(1);
+
+    final FanOutShape4<Integer, String, Integer, String, Integer> unzip = b.graph(UnzipWith.create4(
+      new Function<Integer, Tuple4<String, Integer, String, Integer>>() {
+        @Override public Tuple4<String, Integer, String, Integer> apply(Integer l) throws Exception {
+          return new Tuple4<String, Integer, String, Integer>(l.toString(), l, l + "+" + l, l + l);
+        }
+      })
+    );
+
+    final Sink<String, BoxedUnit> out1 = createSink(probe1);
+    final Sink<Integer, BoxedUnit> out2 = createSink(probe2);
+    final Sink<String, BoxedUnit> out3 = createSink(probe3);
+    final Sink<Integer, BoxedUnit> out4 = createSink(probe4);
+
+    b.edge(b.source(in), unzip.in());
+    b.edge(unzip.out0(), b.sink(out1));
+    b.edge(unzip.out1(), b.sink(out2));
+    b.edge(unzip.out2(), b.sink(out3));
+    b.edge(unzip.out3(), b.sink(out4));
+    b.run(materializer);
+
+    Duration d = Duration.create(300, TimeUnit.MILLISECONDS);
+
+    Object output1 = probe1.receiveOne(d);
+    Object output2 = probe2.receiveOne(d);
+    Object output3 = probe3.receiveOne(d);
+    Object output4 = probe4.receiveOne(d);
+
+    assertEquals("1", output1);
+    assertEquals(1, output2);
+    assertEquals("1+1", output3);
+    assertEquals(2, output4);
+  }
+
   @Test
   public void mustBeAbleToUseZipWith() throws Exception {
     final Source<Integer, BoxedUnit> in1 = Source.single(1);

akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphUnzipSpec.scala

@@ -1,3 +1,6 @@
+/**
+ * Copyright (C) 2014-2015 Typesafe Inc. <http://www.typesafe.com>
+ */
 package akka.stream.scaladsl
 
 import scala.concurrent.duration._

akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphUnzipWithSpec.scala

@@ -0,0 +1,284 @@
+/**
+ * Copyright (C) 2014-2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+package akka.stream.scaladsl
+
+import akka.stream._
+import akka.stream.testkit.TestSubscriber.Probe
+import akka.stream.testkit.Utils._
+import akka.stream.testkit._
+import org.reactivestreams.Publisher
+
+import scala.concurrent.duration._
+import scala.util.control.NoStackTrace
+
+class GraphUnzipWithSpec extends AkkaSpec {
+
+  import FlowGraph.Implicits._
+
+  val settings = ActorMaterializerSettings(system)
+    .withInputBuffer(initialSize = 2, maxSize = 16)
+
+  implicit val materializer = ActorMaterializer(settings)
+
+  val TestException = new RuntimeException("test") with NoStackTrace
+
+  type LeftOutput = Int
+  type RightOutput = String
+
+  abstract class Fixture(b: FlowGraph.Builder[_]) {
+    def in: Inlet[Int]
+    def left: Outlet[LeftOutput]
+    def right: Outlet[RightOutput]
+  }
+
+  val f: (Int ⇒ (Int, String)) = b ⇒ (b + b, b + "+" + b)
+
+  def fixture(b: FlowGraph.Builder[_]): Fixture = new Fixture(b) {
+    val unzip = b.add(UnzipWith[Int, Int, String](f))
+
+    override def in: Inlet[Int] = unzip.in
+
+    override def left: Outlet[Int] = unzip.out0
+
+    override def right: Outlet[String] = unzip.out1
+  }
+
+  def setup(p: Publisher[Int]) = {
+    val leftSubscriber = TestSubscriber.probe[LeftOutput]()
+    val rightSubscriber = TestSubscriber.probe[RightOutput]()
+
+    FlowGraph.closed() { implicit b ⇒
+      val f = fixture(b)
+
+      Source(p) ~> f.in
+      f.left ~> Sink(leftSubscriber)
+      f.right ~> Sink(rightSubscriber)
+
+    }.run()
+
+    (leftSubscriber, rightSubscriber)
+  }
+
+  def validateSubscriptionAndComplete(subscribers: (Probe[LeftOutput], Probe[RightOutput])): Unit = {
+    subscribers._1.expectSubscriptionAndComplete()
+    subscribers._2.expectSubscriptionAndComplete()
+  }
+
+  def validateSubscriptionAndError(subscribers: (Probe[LeftOutput], Probe[RightOutput])): Unit = {
+    subscribers._1.expectSubscriptionAndError(TestException)
+    subscribers._2.expectSubscriptionAndError(TestException)
+  }
+
+  "UnzipWith" must {
+
+    "work with immediately completed publisher" in assertAllStagesStopped {
+      val subscribers = setup(TestPublisher.empty[Int])
+      validateSubscriptionAndComplete(subscribers)
+    }
+
+    "work with delayed completed publisher" in assertAllStagesStopped {
+      val subscribers = setup(TestPublisher.lazyEmpty)
+      validateSubscriptionAndComplete(subscribers)
+    }
+
+    "work with two immediately failed publishers" in assertAllStagesStopped {
+      val subscribers = setup(TestPublisher.error(TestException))
+      validateSubscriptionAndError(subscribers)
+    }
+
+    "work with two delayed failed publishers" in assertAllStagesStopped {
+      val subscribers = setup(TestPublisher.lazyError(TestException))
+      validateSubscriptionAndError(subscribers)
+    }
+
+    "work in the happy case" in {
+      val leftProbe = TestSubscriber.manualProbe[LeftOutput]()
+      val rightProbe = TestSubscriber.manualProbe[RightOutput]()
+
+      FlowGraph.closed() { implicit b ⇒
+        val unzip = b.add(UnzipWith(f))
+        Source(1 to 4) ~> unzip.in
+
+        unzip.out0 ~> Flow[LeftOutput].buffer(4, OverflowStrategy.backpressure) ~> Sink(leftProbe)
+        unzip.out1 ~> Flow[RightOutput].buffer(4, OverflowStrategy.backpressure) ~> Sink(rightProbe)
+      }.run()
+
+      val leftSubscription = leftProbe.expectSubscription()
+      val rightSubscription = rightProbe.expectSubscription()
+
+      leftSubscription.request(2)
+      rightSubscription.request(1)
+
+      leftProbe.expectNext(2)
+      leftProbe.expectNext(4)
+      leftProbe.expectNoMsg(100.millis)
+
+      rightProbe.expectNext("1+1")
+      rightProbe.expectNoMsg(100.millis)
+
+      leftSubscription.request(1)
+      rightSubscription.request(2)
+
+      leftProbe.expectNext(6)
+      leftProbe.expectNoMsg(100.millis)
+
+      rightProbe.expectNext("2+2")
+      rightProbe.expectNext("3+3")
+      rightProbe.expectNoMsg(100.millis)
+
+      leftSubscription.request(1)
+      rightSubscription.request(1)
+
+      leftProbe.expectNext(8)
+      rightProbe.expectNext("4+4")
+
+      leftProbe.expectComplete()
+      rightProbe.expectComplete()
+    }
+
+    "work in the sad case" in {
+      val leftProbe = TestSubscriber.manualProbe[LeftOutput]()
+      val rightProbe = TestSubscriber.manualProbe[RightOutput]()
+
+      FlowGraph.closed() { implicit b ⇒
+        val unzip = b.add(UnzipWith[Int, Int, String]((b: Int) ⇒ (1 / b, 1 + "/" + b)))
+
+        Source(-2 to 2) ~> unzip.in
+
+        unzip.out0 ~> Flow[LeftOutput].buffer(4, OverflowStrategy.backpressure) ~> Sink(leftProbe)
+        unzip.out1 ~> Flow[RightOutput].buffer(4, OverflowStrategy.backpressure) ~> Sink(rightProbe)
+      }.run()
+
+      val leftSubscription = leftProbe.expectSubscription()
+      val rightSubscription = rightProbe.expectSubscription()
+
+      leftSubscription.request(2)
+      leftProbe.expectNext(1 / -2)
+      leftProbe.expectNext(1 / -1)
+
+      rightSubscription.request(1)
+      rightProbe.expectNext("1/-2")
+
+      leftSubscription.request(2)
+      leftProbe.expectError() match {
+        case a: java.lang.ArithmeticException ⇒ a.getMessage should be("/ by zero")
+      }
+      rightProbe.expectError()
+
+      leftProbe.expectNoMsg(100.millis)
+      rightProbe.expectNoMsg(100.millis)
+    }
+
+    "unzipWith expanded Person.unapply (3 ouputs)" in {
+      val probe0 = TestSubscriber.manualProbe[String]()
+      val probe1 = TestSubscriber.manualProbe[String]()
+      val probe2 = TestSubscriber.manualProbe[Int]()
+
+      case class Person(name: String, surname: String, int: Int)
+
+      FlowGraph.closed() { implicit b ⇒
+        val unzip = b.add(UnzipWith((a: Person) ⇒ Person.unapply(a).get))
+
+        Source.single(Person("Caplin", "Capybara", 3)) ~> unzip.in
+
+        unzip.out0 ~> Sink(probe0)
+        unzip.out1 ~> Sink(probe1)
+        unzip.out2 ~> Sink(probe2)
+      }.run()
+
+      val subscription0 = probe0.expectSubscription()
+      val subscription1 = probe1.expectSubscription()
+      val subscription2 = probe2.expectSubscription()
+
+      subscription0.request(1)
+      subscription1.request(1)
+      subscription2.request(1)
+
+      probe0.expectNext("Caplin")
+      probe1.expectNext("Capybara")
+      probe2.expectNext(3)
+
+      probe0.expectComplete()
+      probe1.expectComplete()
+      probe2.expectComplete()
+    }
+
+    "work with up to 20 outputs" in {
+      val probe0 = TestSubscriber.manualProbe[Int]()
+      val probe5 = TestSubscriber.manualProbe[String]()
+      val probe10 = TestSubscriber.manualProbe[Int]()
+      val probe15 = TestSubscriber.manualProbe[String]()
+      val probe19 = TestSubscriber.manualProbe[String]()
+
+      FlowGraph.closed() { implicit b ⇒
+
+        val split20 = (a: (List[Int])) ⇒
+          (a(0), a(0).toString,
+            a(1), a(1).toString,
+            a(2), a(2).toString,
+            a(3), a(3).toString,
+            a(4), a(4).toString,
+            a(5), a(5).toString,
+            a(6), a(6).toString,
+            a(7), a(7).toString,
+            a(8), a(8).toString,
+            a(9), a(9).toString)
+
+        // odd input ports will be Int, even input ports will be String
+        val unzip = b.add(UnzipWith(split20))
+
+        Source.single((0 to 19).toList) ~> unzip.in
+
+        def createSink[T](o: Outlet[T]) =
+          o ~> Flow[T].buffer(1, OverflowStrategy.backpressure) ~> Sink(TestSubscriber.manualProbe[T]())
+
+        unzip.out0 ~> Sink(probe0)
+        createSink(unzip.out1)
+        createSink(unzip.out2)
+        createSink(unzip.out3)
+        createSink(unzip.out4)
+
+        unzip.out5 ~> Sink(probe5)
+        createSink(unzip.out6)
+        createSink(unzip.out7)
+        createSink(unzip.out8)
+        createSink(unzip.out9)
+
+        unzip.out10 ~> Sink(probe10)
+        createSink(unzip.out11)
+        createSink(unzip.out12)
+        createSink(unzip.out13)
+        createSink(unzip.out14)
+
+        unzip.out15 ~> Sink(probe15)
+        createSink(unzip.out16)
+        createSink(unzip.out17)
+        createSink(unzip.out18)
+
+        unzip.out19 ~> Sink(probe19)
+
+      }.run()
+
+      probe0.expectSubscription().request(1)
+      probe5.expectSubscription().request(1)
+      probe10.expectSubscription().request(1)
+      probe15.expectSubscription().request(1)
+      probe19.expectSubscription().request(1)
+
+      probe0.expectNext(0)
+      probe5.expectNext("2")
+      probe10.expectNext(5)
+      probe15.expectNext("7")
+      probe19.expectNext("9")
+
+      probe0.expectComplete()
+      probe5.expectComplete()
+      probe10.expectComplete()
+      probe15.expectComplete()
+      probe19.expectComplete()
+    }
+
+  }
+
+}

akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphZipSpec.scala

@@ -1,5 +1,5 @@
 /**
- * Copyright (C) 2014 Typesafe Inc. <http://www.typesafe.com>
+ * Copyright (C) 2014-2015 Typesafe Inc. <http://www.typesafe.com>
  */
 package akka.stream.scaladsl
 

akka-stream/src/main/boilerplate/akka/japi/Tuple.scala.template

@@ -0,0 +1,21 @@
+/**
+ * Copyright (C) 2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+package akka.japi
+
+[3..22#/**
+ * Used to create tuples with 1 elements in Java.
+ */
+object Tuple1 {
+  def create[[#T1#]]([#t1: T1#]) = new Tuple1([#t1#])
+}
+
+/**
+ * Java API Tuple container.
+ */
+@SerialVersionUID(##1L)
+final case class Tuple1[[#T1#]]([#t1: T1#]) extends scala.Product with scala.Serializable {
+   val toScala = ([#t1#])
+}#
+
+]

akka-stream/src/main/boilerplate/akka/stream/impl/GenJunctions.scala.template

@@ -6,7 +6,7 @@ package akka.stream.impl
 import akka.actor.Props
 import akka.actor.Deploy
 import akka.stream._
-import akka.stream.impl.Junctions.FanInModule
+import akka.stream.impl.Junctions.{ FanInModule, FanOutModule }
 import akka.stream.impl.StreamLayout.Module
 import akka.stream.Attributes
 import akka.stream.Attributes._
@@ -34,4 +34,24 @@ private[akka] object GenJunctions {
   }#
   ]
 
+  sealed trait UnzipWithModule {
+    /** Allows hiding the boilerplate Props creation from the materializer */
+    def props(settings: ActorMaterializerSettings): Props
+  }
+
+  [2..20#
+  final case class UnzipWith1Module[B, [#A1#]](
+    shape: FanOutShape1[B, [#A1#]],
+    f: B ⇒ ([#A1#]),
+    override val attributes: Attributes = name("unzipWith1")) extends FanOutModule with UnzipWithModule {
+
+    override def withAttributes(attr: Attributes): Module = copy(attributes = attr)
+
+    override def carbonCopy: Module = UnzipWith1Module(shape.deepCopy(), f, attributes)
+
+    override def props(settings: ActorMaterializerSettings): Props =
+      Props(new Unzip1With(settings, f.asInstanceOf[Function##1[Any, ([#Any#])]])).withDeploy(Deploy.local)
+  }#
+  ]
+
 }

akka-stream/src/main/boilerplate/akka/stream/impl/UnzipWith.scala.template

@@ -0,0 +1,22 @@
+/**
+ * Copyright (C) 2014-2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+package akka.stream.impl
+
+import akka.stream.ActorMaterializerSettings
+
+[2..20#/** INTERNAL API */
+private[akka] final class Unzip1With(_settings: ActorMaterializerSettings, f: Function##1[Any, ([#Any#])])
+  extends FanOut(_settings, outputCount = 1) {
+
+  outputBunch.markAllOutputs()
+
+  initialPhase(##1, TransferPhase(primaryInputs.NeedsInput && outputBunch.AllOfMarkedOutputs){ () ⇒
+    val elem = primaryInputs.dequeueInputElement()
+    val tuple = f(elem)
+
+    [1..#outputBunch.enqueue(0, tuple._1)#
+    ]
+  })
+}#
+]

akka-stream/src/main/boilerplate/akka/stream/javadsl/UnzipWith.scala.template

@@ -0,0 +1,42 @@
+/**
+ * Copyright (C) 2014 Typesafe Inc. <http://www.typesafe.com>
+ */
+package akka.stream.javadsl
+
+import akka.stream._
+import akka.stream.scaladsl
+import akka.japi.function
+import akka.japi
+
+/**
+ * Split one stream into several streams using a splitting function.
+ *
+ * '''Emits when''' all of the outputs stops backpressuring and there is an input element available
+ *
+ * '''Backpressures when''' any of the outputs backpressures
+ *
+ * '''Completes when''' upstream completes
+ *
+ * '''Cancels when''' any downstream cancels
+ */
+object UnzipWith {
+
+  /**
+   * Create a new `UnzipWith` vertex with the specified input type and unzipping-function `f`.
+   *
+   * @param f unzipping-function from the input value to the pair of output values
+   */
+  def create[In, A, B](f: function.Function[In, japi.Pair[A, B]]):  Graph[FanOutShape2[In, A, B], Unit] =
+    scaladsl.UnzipWith[In, A, B]((in: In) => f.apply(in) match { case japi.Pair(a, b) => (a, b) })
+
+
+  [3..20#/** Create a new `UnzipWith` specialized for 1 outputs.
+   *
+   * @param f unzipping-function from the input value to the output values
+   */
+  def create1[In, [#T1#]](f: function.Function[In, japi.Tuple1[[#T1#]]]): Graph[FanOutShape1[In, [#T1#]], Unit] =
+    scaladsl.UnzipWith[In, [#T1#]]((in: In) => f.apply(in).toScala)#
+
+  ]
+
+}

akka-stream/src/main/boilerplate/akka/stream/scaladsl/UnzipWithApply.scala.template

@@ -0,0 +1,57 @@
+/**
+ * Copyright (C) 2014-2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+package akka.stream.scaladsl
+
+import akka.stream._
+import akka.stream.impl.GenJunctions._
+import akka.stream.impl.StreamLayout
+
+object UnzipWithApply {
+  import scala.language.implicitConversions
+
+  abstract trait UnzipWithCreator[In, Out, T] {
+    def create(unzipper: Function1[In, Out]): T
+  }
+
+  [2..20#trait UnzipWithCreator1[In, [#A1#]] extends UnzipWithCreator[In, Tuple1[[#A1#]], UnzipWith1[In, [#A1#]]] {
+    override def create(unzipper: In ⇒ ([#A1#])): UnzipWith1[In, [#A1#]] = {
+      val shape = new FanOutShape1[In, [#A1#]]("UnzipWith1")
+      new UnzipWith1(shape, new UnzipWith1Module(shape, unzipper, Attributes.name("UnzipWith1")))
+    }
+  }
+
+  implicit object UnzipWithCreatorObject1 extends UnzipWithCreator1[Any, [#Any#]]#
+
+  ]
+}
+
+
+trait UnzipWithApply {
+  import UnzipWithApply._
+
+
+  [2..20#/**
+   * Create a new `UnzipWith` specialized for 1 outputs.
+   *
+   * @param unzipper unzipping-function from the input value to 1 output values
+   */
+   def apply[In, [#A1#]](unzipper: In ⇒ Tuple1[[#A1#]])(implicit creator: UnzipWithCreator1[Any, [#Any#]]): UnzipWith1[In, [#A1#]] = {
+     creator.asInstanceOf[UnzipWithCreator1[In, [#A1#]]].create(unzipper)
+   }#
+
+  ]
+}
+
+[2..20#/** `UnzipWith` specialized for 1 outputs */
+class UnzipWith1[In, [#A1#]] private[stream] (override val shape: FanOutShape1[In, [#A1#]],
+                         private[stream] override val module: StreamLayout.Module)
+  extends Graph[FanOutShape1[In, [#A1#]], Unit] {
+
+  override def withAttributes(attr: Attributes): UnzipWith1[In, [#A1#]] =
+    new UnzipWith1(shape, module.withAttributes(attr).nest())
+
+  override def named(name: String): UnzipWith1[In, [#A1#]] = withAttributes(Attributes.name(name))
+}
+#
+]

akka-stream/src/main/scala/akka/stream/impl/ActorMaterializerImpl.scala

@@ -10,6 +10,7 @@ import akka.dispatch.Dispatchers
 import akka.pattern.ask
 import akka.stream.actor.ActorSubscriber
 import akka.stream.impl.GenJunctions.ZipWithModule
+import akka.stream.impl.GenJunctions.UnzipWithModule
 import akka.stream.impl.Junctions._
 import akka.stream.impl.StreamLayout.Module
 import akka.stream.impl.fusing.ActorInterpreter
@@ -178,8 +179,8 @@ private[akka] case class ActorMaterializerImpl(
               case BalanceModule(shape, waitForDownstreams, _) ⇒
                 (Balance.props(effectiveSettings, shape.outArray.size, waitForDownstreams), shape.in, shape.outArray.toSeq)
 
-              case UnzipModule(shape, _) ⇒
-                (Unzip.props(effectiveSettings), shape.in, shape.outlets)
+              case unzip: UnzipWithModule ⇒
+                (unzip.props(effectiveSettings), unzip.inPorts.head, unzip.shape.outlets)
             }
             val impl = actorOf(props, stageName(effectiveAttributes), effectiveSettings.dispatcher)
             val size = outs.size

akka-stream/src/main/scala/akka/stream/javadsl/Graph.scala

@@ -209,17 +209,13 @@ object Zip {
  * '''Cancels when''' any downstream cancels
  */
 object Unzip {
+  import akka.japi.function.Function
 
   /**
    * Creates a new `Unzip` vertex with the specified output types.
    */
   def create[A, B](): Graph[FanOutShape2[A Pair B, A, B], Unit] =
-    scaladsl.FlowGraph.partial() { implicit b ⇒
-      val unzip = b.add(scaladsl.Unzip[A, B]())
-      val tuple = b.add(scaladsl.Flow[A Pair B].map(p ⇒ (p.first, p.second)))
-      b.addEdge(tuple.outlet, unzip.in)
-      new FanOutShape2(FanOutShape.Ports(tuple.inlet, unzip.out0 :: unzip.out1 :: Nil))
-    }
+    UnzipWith.create(JavaIdentityFunction.asInstanceOf[Function[Pair[A, B], Pair[A, B]]])
 
   /**
    * Creates a new `Unzip` vertex with the specified output types.

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

@@ -240,12 +240,18 @@ object ZipWith extends ZipWithApply
  * '''Cancels when''' any downstream cancels
  */
 object Unzip {
+
+  private final val _identity: Any ⇒ Any = a ⇒ a
+
   /**
    * Create a new `Unzip`.
    */
   def apply[A, B](): Unzip[A, B] = {
     val shape = new FanOutShape2[(A, B), A, B]("Unzip")
-    new Unzip(shape, new UnzipModule(shape, Attributes.name("Unzip")))
+    new Unzip(shape, new UnzipWith2Module[(A, B), A, B](
+      shape,
+      _identity.asInstanceOf[((A, B)) ⇒ (A, B)],
+      Attributes.name("Unzip")))
   }
 }
 
@@ -262,6 +268,19 @@ class Unzip[A, B] private (override val shape: FanOutShape2[(A, B), A, B],
   override def named(name: String): Unzip[A, B] = withAttributes(Attributes.name(name))
 }
 
+/**
+ * Transforms each element of input stream into multiple streams using a splitter function.
+ *
+ * '''Emits when''' all of the outputs stops backpressuring and there is an input element available
+ *
+ * '''Backpressures when''' any of the outputs backpressures
+ *
+ * '''Completes when''' upstream completes
+ *
+ * '''Cancels when''' any downstream cancels
+ */
+object UnzipWith extends UnzipWithApply
+
 object Concat {
   /**
    * Create a new `Concat`.