9

你好，

我将 Scala 2.10 与新的期货库一起使用，我正在尝试编写一些代码来测试无限循环。我使用 ascala.concurrent.Future在单独的线程中运行带有循环的代码。然后我想等一会儿做一些测试，然后杀死单独的线程/未来。我看过，Await.result但这实际上并没有扼杀未来。有什么方法可以超时或终止新的 Scala 2.10 期货？

我宁愿不必为这个简单的部分添加诸如 Akka 之类的外部依赖项。

4

3 回答 3

7

不要在家里尝试。

import scala.concurrent._
import scala.concurrent.duration._

class MyCustomExecutionContext extends AnyRef with ExecutionContext {
  import ExecutionContext.Implicits.global
  @volatile var lastThread: Option[Thread] = None
  override def execute(runnable: Runnable): Unit = {
    ExecutionContext.Implicits.global.execute(new Runnable() {
      override def run() {
        lastThread = Some(Thread.currentThread)
        runnable.run()
      }
    })
  }
  override def reportFailure(t: Throwable): Unit = ???
}    

implicit val exec = new MyCustomExecutionContext()
val f = future[Int]{ do{}while(true); 1 }
try {
  Await.result(f, 10 seconds) // 100% cpu here
} catch {
  case e: TimeoutException => 
    println("Stopping...")
    exec.lastThread.getOrElse(throw new RuntimeException("Not started"))
      .stop() // 0% cpu here
}
于 2013-01-22T01:23:44.043 回答
2

否 - 您必须添加一个循环检查的标志。如果设置了标志，则停止循环。确保标志至少为volatile.

请参阅Java 并发实践，第 135-137 页。

于 2013-01-22T01:22:24.190 回答
1

I had a similar problem and wrote the following nonblocking future op:

class TerminationToken(var isTerminated: Boolean)
object TerminationToken { def apply() = new TerminationToken(false) }

 implicit class FutureOps[T](future: Future[Option[T]]) {
 def terminate(timeout: FiniteDuration, token: TerminationToken): Future[Option[T]] = {
   val timeoutFuture = after[Option[T]](timeout, using = context.system.scheduler) {
     Future[Option[T]] { token.isTerminated = true; None } }
          Future.firstCompletedOf[Option[T]](Seq (future recover { case _ => None }, timeoutFuture))
     }
   }

Then just create a future that returns an option, and use .terminate(timeout, token) on it

于 2013-11-28T17:20:27.640 回答