Hello there,
welcome to the akka community! :-)
By looking at the API I assume you’re using scala’s
scala.concurrent.Future[T].
You should probably start out by reading the core scala docs about futures:
http://docs.scala-lang.org/*overviews/core/futures.html*
<http://docs.scala-lang.org/overviews/core/futures.html>
as well as our docs (java version): http://doc.akka.io/docs/akka/
*2.3.3/java/futures.html*
<http://doc.akka.io/docs/akka/2.3.3/java/futures.html>
To answer your questions:
In order to get the value out you’d usually use foreach or map: (I did the
examples below in Scala for conciseness, everything is available for Java -
see the akka docs about futures - linked above)
val f: Future[String] = Future { "Hello" }
val f2: Future[String] = f map { h => h + " world!" } // that's async
Of course you can reply to some actor in the callback (but be sure to first
freeze the sender value in a value! (val replyTo = sender(); Future { ... }
map { replyTo ! _ })
You can also use onSuccess for this, the API is a bit different, and
use-case wise it's more for "once this future completes, do a side-effect",
whereas map is more about "transform this data".
Await does cause blocking behaviour - try to avoid it.
On Wed, Jun 4, 2014 at 1:27 PM, Yadukrishnan K <[email protected]> wrote:
> I am new to Akka.
> I would like to know how to return some result from onSuccess method.
>
> I mean, If I would like to extract the response from an actor after it
> executes completely. I need to get the result and add some extra messages
> and send the result back to the rest client.
>
> I am not able to find out if it is possible to do so.
>
> //in my rest controller
>
> Future<Object> future = getItemService(id);
> future.onSuccess(
> //retrieve the result fromthe future and wrap the result
> with some extra info and return to the caller );
>
> Is there any way to do that?
>
> I also know that we can use Await and then convert the result. But wont
> it affect the asynchronous behaviour ?
>
> --
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--
Cheers,
Konrad 'ktoso' Malawski
hAkker - Typesafe, Inc
<http://scaladays.org>
--
>>>>>>>>>> Read the docs: http://akka.io/docs/
>>>>>>>>>> Check the FAQ:
>>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html
>>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user
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