Akka doc is unclear about how to get an ExtendedActorSystem to deserialize ActorRef

Question

I'm trying to serialize/deserialize ActorRef through protobuf. According to the Akka doc, the only way to do it is to convert the ActorRef into a String, and convert it back in the remote actor system.

The doc mentions using an ExtendedActorSystem to do the deserialization (see here). However, it is unclear how to get the ExtendedActorSystem:

// Serialize
// (beneath toBinary)
val identifier: String = Serialization.serializedActorPath(theActorRef)

// Then just serialize the identifier however you like

// Deserialize
// (beneath fromBinary)
// ==== Where is this extendedSystem from? ====
val deserializedActorRef = extendedSystem.provider.resolveActorRef(identifier)
// Then just use the ActorRef

Edit

I found this question here: Akka (JVM): Serialize an actorref with protobuf within another message, which mentions casting an ActorSystem to ExtendedActorSystem. Is this the right approach? Will it always work?

Answer 1

dear @stackoverflower,

whenever you use ActorSystem(...) it build an instance of ActorSystemImpl.

The type-tree looks like:

ActorSystemImpl extends ExtendedActorSystem

and

ExtendedActorSystem implements ActorSystem

you can use statements like

val system: ExtendedActorSystem = ActorSystem(...).asInstanceOf[ExtendedActorSystem]

to access the correct type autocomplete. ActorSystemImpl is unfortunately scoped to [akka].