Scala/Java 枚举

我读了this https://stackoverflow.com/questions/1321745/scala-doesnt-have-enums-what-to-use-instead-of-an-enum and this https://stackoverflow.com/questions/1898932/case-classes-vs-enumerations-in-scala，但我仍然不明白在 Scala 中执行此操作的（惯用）等效方法

enum Status { 
    OK(1, "Ok", "Okay"),
    NOT_OK(5, "Not Ok", "Not Okay")
    BAD(10, "Bad", "Run for your life")

    int code;
    String name;
    String description; // custom fields

    Status(int code, String name, String description) {
        this.code = code;
        this.name = name;
        this.description = description;
    }
}

class Main {
    public static void main(String[] args) {
        for(Status status : Status.values) { // iterate through them
            doStuff(status);
        }
    }

    private doStuff(Status status) {
        System.out.println(status.description);
        // and more
    }
}

在 Scala 中，您可以创建一个类似于 Java 中的“enum”的枚举结构。基本上，您需要做的只是扩展scala.枚举类 http://www.scala-lang.org/api/current/index.html#scala.Enumeration如果您需要一个更复杂的类作为枚举，则可以扩展 Val 类。否则，您可以使用默认的 Val 类，它接受 Int 或 String 或两者。下面是 Java 代码的 Scala 版本。

object Status extends Enumeration {

  case class StatusVal(code: Int, name: String, description: String) extends Val

  val OK = StatusVal(1, "Ok", "Okay")
  val NOT_OK = StatusVal(1, "Not Ok", "Not Okay")
  val BAD = StatusVal(1, "Bad", "Run for your life")
}

object Application extends App {
  Status.values foreach (s => println(s.asInstanceOf[StatusVal].description))
}