How to guarantee sequentiality for forks in akka

Question

We\'re creating a chain of actors for every (small) incoming group of messages to guarantee their sequential processing and piping (groups are differentiating by common id).

Answer 1

The simpler solution is to store a future for last received message into the actor's state and chain it with previous future:

def receive = process(Future{new Ack}) //completed future
def process(prevAck: Future[Ack]): Receive = { //pseudocode
    case x => ...
        context become process(prevAck.flatMap(_ => A2orA4 ? msg))
}

So it will create chain of futures without any blocking. The chain will be erased after futures completion (except the last one).