As for implementation, I'd probably do something like this: (WARNING: NOT
COMPILED)
import akka.pattern.after
def keepAsking(recipient: ActorRef, msg: Any, every:
FiniteDuration)(implicit ec: ExecutionContext, scheduler: Scheduler):
Future[Any] = {
def retry(): Future[Any] = after(every, scheduler)((recipient ?
msg)(every)) recoverWith { case _ => retry() }
retry()
}
On Wed, Jan 15, 2014 at 6:22 PM, √iktor Ҡlang <[email protected]>wrote:
>
>
>
> On Wed, Jan 15, 2014 at 6:11 PM, Simon Schäfer <[email protected]> wrote:
>
>> I have the following code:
>>
>> import scala.concurrent.Future
>> import scala.concurrent.Promise
>> import scala.concurrent.duration.DurationInt
>> import scala.concurrent.duration.FiniteDuration
>>
>> import akka.actor.Actor
>> import akka.actor.ActorRef
>> import akka.pattern.ask
>> import akka.util.Timeout.durationToTimeout
>>
>> trait ActorHelpers {
>>
>> self: Actor =>
>>
>> import context.dispatcher
>>
>> def keepAsking(recipient: ActorRef, msg: Any, interval:
>> FiniteDuration): Future[Any] = {
>> val p = Promise[Any]()
>> val cancel = context.system.scheduler.schedule(0.millis, interval) {
>> if (context != null)
>> (recipient ? msg)(1.hour) foreach p.trySuccess
>> }
>> val f = p.future
>> f.onComplete(_ => cancel.cancel())
>> f
>> }
>>
>> }
>>
>> The idea of this code snippet is that a message is resend as long as an
>> answer is retrieved. The problem is that I sometimes get a NPE on the line
>> that contains the ask.
>>
>> Without the check if context is null I get even more NPEs. I don't
>> understand why I get NPEs here, because I can't see where context or some
>> of its state is accessed. Can someone explain it?
>>
>
> Hint: remove import context.dispatcher
>
>
>>
>> --
>> >>>>>>>>>> Read the docs: http://akka.io/docs/
>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/
>> >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user
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>>
>
>
>
> --
> Cheers,
> √
>
> * Viktor Klang*
> *Director of Engineering*
> Typesafe <http://www.typesafe.com/>
>
> Twitter: @viktorklang
>
--
Cheers,
√
*Viktor Klang*
*Concurrent, Distributed*
Twitter: @viktorklang
--
>>>>>>>>>> Read the docs: http://akka.io/docs/
>>>>>>>>>> Check the FAQ: http://akka.io/faq/
>>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user
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