Akka Typed cleanups

play-java-websocket-example/app/Module.java

@@ -71,17 +71,15 @@ public ActorRef<UserParentActor.Create> get() {
     @Singleton
     public static class UserActorFactoryProvider implements Provider<UserActor.Factory> {
         private final ActorRef<StocksActor.GetStocks> stocksActor;
-        private final Materializer mat;
 
         @Inject
         public UserActorFactoryProvider(ActorRef<StocksActor.GetStocks> stocksActor, Materializer mat) {
             this.stocksActor = stocksActor;
-            this.mat = mat;
         }
 
         @Override
         public UserActor.Factory get() {
-            return id -> UserActor.create(id, stocksActor, mat);
+            return id -> UserActor.create(id, stocksActor);
         }
     }
 }

play-java-websocket-example/app/actors/UserActor.java

@@ -66,6 +66,14 @@ public String toString() {
         }
     }
 
+    private static final class InternalStop implements Message {
+        private static final InternalStop INSTANCE = new InternalStop();
+        public static InternalStop get() {
+            return INSTANCE;
+        }
+        private InternalStop() {}
+    }
+
     private final Duration timeout = Duration.of(5, ChronoUnit.MILLIS);
 
     private final Map<String, UniqueKillSwitch> stocksMap = new HashMap<>();
@@ -79,19 +87,17 @@ public String toString() {
     private final Sink<JsonNode, NotUsed> hubSink;
     private final Flow<JsonNode, JsonNode, NotUsed> websocketFlow;
 
-    public static Behavior<Message> create(String id,
-                                           ActorRef<GetStocks> stocksActor,
-                                           Materializer mat) {
-        return Behaviors.setup(context -> new UserActor(id, stocksActor, mat, context).behavior());
+    public static Behavior<Message> create(String id, ActorRef<GetStocks> stocksActor) {
+        return Behaviors.setup(context -> new UserActor(id, stocksActor, context).behavior());
     }
 
     @Inject
     public UserActor(String id,
                      ActorRef<GetStocks> stocksActor,
-                     Materializer mat, ActorContext<Message> context) {
+                     ActorContext<Message> context) {
         this.id = id;
         this.stocksActor = stocksActor;
-        this.mat = mat;
+        this.mat = Materializer.matFromSystem(context.getSystem());
         this.scheduler = context.getSystem().scheduler();
         this.context = context;
 
@@ -116,7 +122,7 @@ public UserActor(String id,
                 //.log("actorWebsocketFlow", logger)
                 .watchTermination((n, stage) -> {
                     // When the flow shuts down, make sure this actor also stops.
-                    stage.thenAccept(f -> context.stop(context.getSelf())); // XXX: is self a child?
+                    context.pipeToSelf(stage, (Done _done, Throwable _throwable) -> InternalStop.get());
                     return NotUsed.getInstance();
                 });
     }
@@ -135,6 +141,7 @@ public Behavior<Message> behavior() {
                 unwatchStocks(unwatchStocks.symbols);
                 return Behaviors.same();
             })
+            .onMessageEquals(InternalStop.get(), Behaviors::stopped)
             .onSignal(PostStop.class, _postStop -> {
                 // If this actor is killed directly, stop anything that we started running explicitly.
                 context.getLog().info("Stopping actor {}", context.getSelf());

play-scala-websocket-example/app/actors/UserActor.scala

@@ -4,7 +4,7 @@ import javax.inject._
 
 import actors.StocksActor.{ GetStocks, Stocks }
 import akka.actor.typed.scaladsl.{ ActorContext, Behaviors }
-import akka.actor.typed.{ ActorRef, Behavior, PostStop, Scheduler }
+import akka.actor.typed.{ ActorRef, ActorSystem, Behavior, PostStop, Scheduler }
 import akka.stream._
 import akka.stream.scaladsl._
 import akka.util.Timeout
@@ -15,26 +15,25 @@ import stocks._
 
 import scala.concurrent.duration._
 import scala.concurrent.{ ExecutionContext, Future }
+import scala.util.Try
 
 /**
  * Creates a user actor that sets up the websocket stream.  Although it's not required,
  * having an actor manage the stream helps with lifecycle and monitoring, and also helps
  * with dependency injection through the AkkaGuiceSupport trait.
  *
  * @param stocksActor the actor responsible for stocks and their streams
- * @param ec          implicit CPU bound execution context.
  */
 class UserActor @Inject()(id: String, stocksActor: ActorRef[GetStocks])(implicit
-    mat: Materializer,
-    ec: ExecutionContext,
-    scheduler: Scheduler,
     context: ActorContext[UserActor.Message],
 ) {
   import UserActor._
 
   val log: Logger = context.log
 
-  implicit val timeout = Timeout(50.millis)
+  implicit val timeout: Timeout             = Timeout(50.millis)
+  implicit val system: ActorSystem[Nothing] = context.system
+  import context.executionContext
 
   val (hubSink, hubSource) = MergeHub.source[JsValue](perProducerBufferSize = 16)
     .toMat(BroadcastHub.sink(bufferSize = 256))(Keep.both)
@@ -58,6 +57,9 @@ class UserActor @Inject()(id: String, stocksActor: ActorRef[GetStocks])(implicit
       case UnwatchStocks(symbols) =>
         unwatchStocks(symbols)
         Behaviors.same
+
+      case InternalStop =>
+        Behaviors.stopped
     }.receiveSignal {
       case (_, PostStop) =>
         // If this actor is killed directly, stop anything that we started running explicitly.
@@ -78,7 +80,7 @@ class UserActor @Inject()(id: String, stocksActor: ActorRef[GetStocks])(implicit
     // from the browse), using a coupled sink and source.
     Flow.fromSinkAndSourceCoupled(jsonSink, hubSource).watchTermination() { (_, termination) =>
       // When the flow shuts down, make sure this actor also stops.
-      termination.foreach((_: Done) => context.stop(context.self)) // XXX: is self a child?
+      context.pipeToSelf(termination)((_: Try[Done]) => InternalStop)
       NotUsed
     }
   }
@@ -160,6 +162,8 @@ object UserActor {
     require(symbols.nonEmpty, "Must specify at least one symbol!")
   }
 
+  private case object InternalStop extends Message
+
   trait Factory {
     def apply(id: String): Behavior[Message]
   }