Akka Actors with Scala

1. Go through all of this page without visiting the links.
2. Study the source code of Akka examples described in ./akkaPractical.html lecture notes. Equally importantly build and run these.
3. Study the Required Reading References listed.
4. Re-visit this page.

Example of a Future: Below, s.getFriends is a normal method. Had we not enclosed it inside the future braces, control would not return until this method completes. The value f is a future object that encapsulates the computation that is inside the getFriends method. The computation is not yet scheduled, but will be.

import scala.concurrent.{ future, promise }
import scala.concurrent.ExecutionContext.Implicits.global
val s = socialNetwork.createSessionFor("user", credentials)
val f: Future[List[Friend]] = future {
  s.getFriends()           // may take a while
}

Example of a Promise: We re-do the well-known producer-consumer.

import scala.concurrent.{ future, promise }
import scala.concurrent.ExecutionContext.Implicits.global
val p = promise[T]                 // T is unimportant for now
val f = p . future                 // extra spaces for clarity
val prdcr = future {               // producer
  val r = produceSomething()
  p . success . r
  continueDoingSomethingUnrelated()
}
val cnsmr = future {              // consumer
  startDoingSomething()
  f . onSuccess {
    case r => doSomethingWithResult()
  }}

1. Introduction to Akka. Required Reading
2. Part 1: Actor Architecture. Required Reading
3. Part 2: Creating the First Actor. Required Reading
4. Part 3: Working with Device [in the small] Actors Optional Reading
5. Part 4: Working with Device Groups Optional Reading
6. Part 5: Querying Device Groups Optional Reading