访问ExecutionContext

Question

我有这样的特点

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)     
}

我想以这样的另一个特性访问ExecutionContext

trait AsyncGoodness extends NonBlockingGoodness {
  import akka.dispatch.Future

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

但是，我得到了错误。

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

更新：我想出了如何在范围内获取ExecutionContext

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

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

不过，我还有个后续问题。由于在AsyncGoodness中可能有多个使用ExecutionContext的方法，是否有一种方法可以在trait级别传递它，而不是像上面那样在每个方法上传递它。

Answer 1

事实证明，我所需要做的就是显式指定ec返回类型，供编译器使用。这是工作代码

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." }
  }

Answer 2

我知道你不想进口任何额外的东西，但是像这样的东西应该适合你。

trait NonBlockingGoodness {
  import scala.concurrent.{ Future, ExecutionContext }
  import scala.concurrent.util.duration._
  import akka.util.Timeout

  object Implicit {
     implicit val ec = ExecutionContext.Implicits.global
     implicit lazy val timeout = Timeout(5 seconds)
  }

}

trait AsyncGoodness extends NonBlockingGoodness {
  import scala.concurrent.Future
  import Implicit._
  def doSomething = {
    Future { "Future is the bomb." }
  }
}