Question

I have this trait

trait NonBlockingGoodness extends DataStore {
  import akka.dispatch.{ Future, ExecutionContext }
  import akka.util.duration._
  import akka.util.Timeout

  implicit val ec = ExecutionContext.fromExecutorService(yourExecutorServiceGoesHere)
  implicit lazy val timeout = Timeout(5 seconds)     
}

I would like to access the ExecutionContext in another trait like such

trait AsyncGoodness extends NonBlockingGoodness {
  import akka.dispatch.Future

  def doSomething = {
    Future { "Future is the bomb." }
  }

However, I am getting the error

Could not find implicit value for parameter executor: akka.dispatch.ExecutionContext

UPDATED:
I figured out how to get the ExecutionContext in scope

trait AsyncGoodness extends NonBlockingGoodness {
  import akka.dispatch.ExecutionContext
  import akka.dispatch.Future

  def doSomething()(implicit executor: ExecutionContext) = {
    Future { "Future is the bomb." }
  }

However, I have a follow-up question. Since I may have more than 1 method in AsyncGoodness that uses ExecutionContext, is there a way to pass it in at the trait level instead of at each method like I did above.

Answer 1

As it turns out, all I need to do is explicitly specify ec return type for the compiler to use it. Here’s the working code

trait NonBlockingGoodness extends DataStore {
  import akka.dispatch.{ Future, ExecutionContext }
  import akka.util.duration._
  import akka.util.Timeout

  implicit val ec: ExecutionContext = ExecutionContext.fromExecutorService(yourExecutorServiceGoesHere)
  implicit lazy val timeout = Timeout(5 seconds)     
}

trait AsyncGoodness extends NonBlockingGoodness {
  import akka.dispatch.Future

  def doSomething = {
    Future { "Future is the bomb." }
  }