add new Streams Quick Start

also move IOResult to akka.stream package

akka-docs/rst/scala/code/docs/stream/QuickStartDocSpec.scala

@@ -0,0 +1,75 @@
+/**
+ * Copyright (C) 2016 Typesafe Inc. <http://www.typesafe.com>
+ */
+package docs.stream
+
+//#imports
+import akka.stream._
+import akka.stream.scaladsl._
+//#imports
+import akka.{ NotUsed, Done }
+import akka.actor.ActorSystem
+import akka.util.ByteString
+
+import org.scalatest._
+import org.scalatest.concurrent._
+import scala.concurrent._
+import scala.concurrent.duration._
+import java.io.File
+
+class QuickStartDocSpec extends WordSpec with BeforeAndAfterAll with ScalaFutures {
+  implicit val patience = PatienceConfig(5.seconds)
+
+  //#create-materializer
+  implicit val system = ActorSystem("QuickStart")
+  implicit val materializer = ActorMaterializer()
+  //#create-materializer
+
+  override def afterAll(): Unit = {
+    system.terminate()
+  }
+
+  "demonstrate Source" in {
+    //#create-source
+    val source: Source[Int, NotUsed] = Source(1 to 100)
+    //#create-source
+
+    //#run-source
+    source.runForeach(i => println(i))(materializer)
+    //#run-source
+
+    //#transform-source
+    val factorials = source.scan(BigInt(1))((acc, next) => acc * next)
+
+    val result: Future[IOResult] =
+      factorials
+        .map(num => ByteString(s"$num\n"))
+        .runWith(FileIO.toFile(new File("factorials.txt")))
+    //#transform-source
+
+    //#use-transformed-sink
+    factorials.map(_.toString).runWith(lineSink("factorial2.txt"))
+    //#use-transformed-sink
+
+    //#add-streams
+    val done: Future[Done] =
+      factorials
+        .zipWith(Source(0 to 100))((num, idx) => s"$idx! = $num")
+        .throttle(1, 1.second, 1, ThrottleMode.shaping)
+        //#add-streams
+        .take(3)
+        //#add-streams
+        .runForeach(println)
+    //#add-streams
+
+    done.futureValue
+  }
+
+  //#transform-sink
+  def lineSink(filename: String): Sink[String, Future[IOResult]] =
+    Flow[String]
+      .map(s => ByteString(s + "\n"))
+      .toMat(FileIO.toFile(new File(filename)))(Keep.right)
+  //#transform-sink
+
+}