期货回避计算方法 [英] Computation with Futures avoiding Await method

问题描述

我很高兴地调用了computeParallel()函数，该函数正在调用3 Futures F1，F2，F3并返回String作为返回类型.

I have funtion which is calling computeParallel() function which is calling 3 Futures F1,F2,F3 and returning String as return type.

def computeParallel():String =
{

      val f1 = Future {  "ss" }
      val f2 = Future { "sss" }
      val f3 = Future { "ssss" }

      val result: Future[String] = for {
        r1 <- f1
        r2 <- f2
        r3 <- f3
      } yield (r1 + r2 + r3)

    Await.result(result,scala.concurrent.duration.Duration.Inf)



} 

使用Await收集汇总结果.但是人们说使用Await是不好的编码方式.

Using Await to collect the Aggregated Results.But People are saying usage of Await is Bad way of coding.

所以我用的是下面的一种.这将返回Unit类型.

So i have used below one.Which is returning the Unit type.

        result.onComplete {
          case Success(res) => return res
        }

因此，如果返回单位我无法打印任何内容.

So if return Unit i cannot print anything.

有什么可以帮助我们的吗?还有其他解决方法吗

can any help us.Is there anyother way to solve the problem

预先感谢

推荐答案

如果computeParallel必须返回String，则必须Await.result.

If computeParallel must return String you have to Await.result.

良好的编码方式"是您一接触期货就可以使用它.

"Good way of coding" is to work with futures as soon as you get into them.

def computeParallel(): Future[String] = {
  val f1 = Future {  "ss" }
  val f2 = Future { "sss" }
  val f3 = Future { "ssss" }

  for {
    r1 <- f1
    r2 <- f2
    r3 <- f3
  } yield (r1 + r2 + r3)
} 

computeParallel().map(result => ???)

return通常不应在Scala中使用.

return normally shouldn't be used in Scala.

onComplete不能帮忙，因为它

在任意(未指定)线程上运行...

runs on some arbitrary (unspecified) thread ...

我们不会阻止它，直到它完成.

and we don't block until it completes.

Await.result与futures.on之间的差异

承诺可以在将来完成，所以您将再次拥有Future[String]而不是String.

Promise can be completed to future so again you'll have Future[String] rather than String.

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