使用Scala 2.10反射，如何列出Enumeration的值？ [英] Using Scala 2.10 reflection how can I list the values of Enumeration?

问题描述

具有以下枚举

object ResponseType extends Enumeration {
  val Listing, Album = Value
}

如何获取其值列表？

推荐答案

如果要对此进行详细介绍，则需要检查您的符号是否具有 Value 作为超类型：

If you want to be thorough about this, you need to check that your symbols have Value as a supertype:

def valueSymbols[E <: Enumeration: TypeTag] = {
  val valueType = typeOf[E#Value]
  typeOf[E].members.filter(sym => !sym.isMethod &&
    sym.typeSignature.baseType(valueType.typeSymbol) =:= valueType
  )
}

现在，即使您具有以下条件（完全合法）：

Now even if you have the following (which is perfectly legal):

object ResponseType extends Enumeration {
  val Listing, Album = Value
  val someNonValueThing = "You don't want this in your list of value symbols!"
}

您仍然会得到正确的答案：

You still get the correct answer:

scala> valueSymbols[ResponseType.type] foreach println
value Album
value Listing

您的当前方法将在此处包含 value someNonValueThing 。

Your current approach would include value someNonValueThing here.

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