+doc #19429 initial merge of docs-dev and docs

akka-docs/rst/java/code/docs/stream/javadsl/cookbook/RecipeKeepAlive.java

@@ -0,0 +1,58 @@
+/**
+ *  Copyright (C) 2015 Typesafe <http://typesafe.com/>
+ */
+package docs.stream.javadsl.cookbook;
+
+import akka.actor.ActorSystem;
+import akka.stream.ActorMaterializer;
+import akka.stream.Materializer;
+import akka.stream.javadsl.Flow;
+import akka.testkit.JavaTestKit;
+import akka.util.ByteString;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import scala.runtime.BoxedUnit;
+
+import java.util.concurrent.TimeUnit;
+
+public class RecipeKeepAlive extends RecipeTest {
+  static ActorSystem system;
+
+  @BeforeClass
+  public static void setup() {
+    system = ActorSystem.create("RecipeKeepAlive");
+  }
+
+  @AfterClass
+  public static void tearDown() {
+    JavaTestKit.shutdownActorSystem(system);
+    system = null;
+  }
+
+  final Materializer mat = ActorMaterializer.create(system);
+
+  class Tick {}
+  public final Tick TICK = new Tick();
+
+  @Test
+  public void workForVersion1() throws Exception {
+    new JavaTestKit(system) {
+      {
+        final ByteString keepAliveMessage = ByteString.fromArray(new byte[]{11});
+
+        //@formatter:off
+        //#inject-keepalive
+        Flow<ByteString, ByteString, BoxedUnit> keepAliveInject =
+          Flow.of(ByteString.class).keepAlive(
+              scala.concurrent.duration.Duration.create(1, TimeUnit.SECONDS),
+              () -> keepAliveMessage);
+        //#inject-keepalive
+        //@formatter:on
+
+        // Enough to compile, tested elsewhere as a built-in stage
+      }
+    };
+  }
+
+}