The ask-pattern implements the initiator side of a request–reply protocol.
Note that if you are inside of an actor you should prefer ActorContext.ask
as that provides better safety.
The party that asks may be within or without an Actor, since the
implementation will fabricate a (hidden) ActorRef that is bound to a
CompletableFuture. This ActorRef will need to be injected in the
message that is sent to the target Actor in order to function as a reply-to
address, therefore the argument to the ask method is not the message itself
but a function that given the reply-to address will create the message.
The ask-pattern implements the initiator side of a request–reply protocol.
Note that if you are inside of an actor you should prefer ActorContext.ask as that provides better safety.
The party that asks may be within or without an Actor, since the implementation will fabricate a (hidden) ActorRef that is bound to a
CompletableFuture. This ActorRef will need to be injected in the message that is sent to the target Actor in order to function as a reply-to address, therefore the argument to the ask method is not the message itself but a function that given the reply-to address will create the message.