+doc #15239: Stream cookbook

akka-docs-dev/rst/scala/code/docs/stream/cookbook/RecipeSimpleDrop.scala

@@ -0,0 +1,46 @@
+package docs.stream.cookbook
+
+import akka.stream.scaladsl.{ Flow, Sink, Source }
+import akka.stream.testkit.StreamTestKit
+import akka.stream.testkit.StreamTestKit.{ SubscriberProbe, PublisherProbe }
+
+import scala.concurrent.duration._
+
+class RecipeSimpleDrop extends RecipeSpec {
+
+  "Recipe for simply dropping elements for a faster stream" must {
+
+    "work" in {
+
+      //#simple-drop
+      val droppyStream: Flow[Message, Message] =
+        Flow[Message].conflate(seed = identity)((lastMessage, newMessage) => newMessage)
+      //#simple-drop
+
+      val pub = PublisherProbe[Message]()
+      val sub = SubscriberProbe[Message]()
+      val messageSource = Source(pub)
+      val sink = Sink(sub)
+
+      messageSource.via(droppyStream).to(sink).run()
+
+      val manualSource = new StreamTestKit.AutoPublisher(pub)
+
+      val subscription = sub.expectSubscription()
+      sub.expectNoMsg(100.millis)
+
+      manualSource.sendNext("1")
+      manualSource.sendNext("2")
+      manualSource.sendNext("3")
+
+      subscription.request(1)
+      sub.expectNext("3")
+
+      manualSource.sendComplete()
+      subscription.request(1)
+      sub.expectComplete()
+    }
+
+  }
+
+}