在 scala actor 中传递集合

发布于 2024-12-19 05:06:33 字数 329 浏览 0 评论 0原文

当我需要将类型化集合传递给参与者时，我在 react 方法中收到“未检查”警告：

val actor = actor {
  loop {
    react {
      case a:List[String] => // do something
    }
  }
}

如何解决此问题？我尝试在一个单独的类中对集合进行拳击（但这很丑陋且麻烦），并且在之后仅转换集合（case a:List[_] => a.asInstanceOf[List[String]]）由 actor 接收它不是类型安全且危险的。

原文

When I need to pass typed collections to an actor, I get an "unchecked" warning in my react method:

val actor = actor {
  loop {
    react {
      case a:List[String] => // do something
    }
  }
}

How can I work around this? I tried boxing collection in a separate class (but that is ugly and cumbersome), and just casting collection (case a:List[_] => a.asInstanceOf[List[String]]) after receiving it by actor is not type-safe and dangerous.

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若言繁花未落 2024-12-26 05:06:33

由于 JVM 不会跟踪泛型的类型，因此您无法知道 List[_] 是 List[String]，除非您检查每个元素并检查它是否是一个字符串。事实上，最好的选择是将集合放入一个单独的类中。事情不必那么糟糕！

case class StringsBox(ls: List[String]) {}

//...
myactor ! StringsBox( List("these","are","strings") )

//...
react {
  case StringsBox(ls) =>  /* Now you have your List[String] */
}

Because the JVM does not keep track of the type of generics, you can't know that a List[_] is a List[String] unless you examine every element and check that it is a string. Your best bet is in fact to box the collection in a separate class. It need not be so bad!

case class StringsBox(ls: List[String]) {}

//...
myactor ! StringsBox( List("these","are","strings") )

//...
react {
  case StringsBox(ls) =>  /* Now you have your List[String] */
}

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