如何在 Akka Classic 中向演员的父母发送消息？

Question

What is the method for an actor to send a message to its parent?

I'm using Akka 2.2

Answer 1

You are looking for

getContext().parent()

which gives you the ActorRef of the parent, so you can do

getContext().parent().tell(...)

Answer 2

With Akka 2.4, you have to do context.parent inside an actor to have its parent actor reference. After that, you can send it a message as before ( context.parent ! "hello" ).

Answer 3

It should be noted, eg for anybody who comes to this question through a search, that Akka 2.6 introduces a typed API for interacting with and defining actors and that the docs starting in version 2.6 guide towards using the typed API.

In an actor defined using the typed API, the ActorContext no longer directly provides an ActorRef to the parent actor, so the answers above won't work. See this question for a (Scala) solution in Akka Typed. The analogous Java API would be:

import akka.actor.typed.javadsl.Adapter

ActorRef parent = Adapter.toClassic(getContext()).parent()

Note that this is an untyped ActorRef : you can send any message to the parent actor, but the parent actor is not under any obligation to accept the message you send.