rename akka-docs dir to docs (#62)

docs/src/test/java/jdocs/stream/RestartDocTest.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2015-2022 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+package jdocs.stream;
+
+import org.apache.pekko.NotUsed;
+import org.apache.pekko.actor.ActorSystem;
+import org.apache.pekko.stream.KillSwitch;
+import org.apache.pekko.stream.KillSwitches;
+import org.apache.pekko.stream.Materializer;
+import org.apache.pekko.stream.RestartSettings;
+import org.apache.pekko.stream.javadsl.Keep;
+import org.apache.pekko.stream.javadsl.RestartSource;
+import org.apache.pekko.stream.javadsl.Sink;
+import org.apache.pekko.stream.javadsl.Source;
+
+import java.time.Duration;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+
+public class RestartDocTest {
+
+  static ActorSystem system;
+  static Materializer materializer;
+
+  // Mocking akka-http
+  public static class Http {
+    public static Http get(ActorSystem system) {
+      return new Http();
+    }
+
+    public CompletionStage<Http> singleRequest(String uri) {
+      return new CompletableFuture<>();
+    }
+
+    public NotUsed entity() {
+      return NotUsed.getInstance();
+    }
+  }
+
+  public static class HttpRequest {
+    public static String create(String uri) {
+      return uri;
+    }
+  }
+
+  public static class ServerSentEvent {}
+
+  public static class EventStreamUnmarshalling {
+    public static EventStreamUnmarshalling fromEventStream() {
+      return new EventStreamUnmarshalling();
+    }
+
+    public CompletionStage<Source<ServerSentEvent, NotUsed>> unmarshall(
+        Http http, Materializer mat) {
+      return new CompletableFuture<>();
+    }
+  }
+
+  public void doSomethingElse() {}
+
+  public void recoverWithBackoffSource() {
+    // #restart-with-backoff-source
+    RestartSettings settings =
+        RestartSettings.create(
+                Duration.ofSeconds(3), // min backoff
+                Duration.ofSeconds(30), // max backoff
+                0.2 // adds 20% "noise" to vary the intervals slightly
+                )
+            .withMaxRestarts(
+                20, Duration.ofMinutes(5)); // limits the amount of restarts to 20 within 5 minutes
+
+    Source<ServerSentEvent, NotUsed> eventStream =
+        RestartSource.withBackoff(
+            settings,
+            () ->
+                // Create a source from a future of a source
+                Source.completionStageSource(
+                    // Issue a GET request on the event stream
+                    Http.get(system)
+                        .singleRequest(HttpRequest.create("http://example.com/eventstream"))
+                        .thenCompose(
+                            response ->
+                                // Unmarshall it to a stream of ServerSentEvents
+                                EventStreamUnmarshalling.fromEventStream()
+                                    .unmarshall(response, materializer))));
+    // #restart-with-backoff-source
+
+    // #with-kill-switch
+    KillSwitch killSwitch =
+        eventStream
+            .viaMat(KillSwitches.single(), Keep.right())
+            .toMat(Sink.foreach(event -> System.out.println("Got event: " + event)), Keep.left())
+            .run(materializer);
+
+    doSomethingElse();
+
+    killSwitch.shutdown();
+    // #with-kill-switch
+
+  }
+}