Scala:如何检查是否至少定义了一个类的字段？

Question

我有一个类，它有几个可选字段，如下所示:

class Container(f1: Option[String] = None,
                f2: Option[Boolean] = None,
                f3: Option[Int] = None,
                f4: Option[String] = None
                // ... 30 other fields which is unfortunate/terrible and
                // cannot be changed at the moment
                 ) {
  def hasAtleastOneDefinedField: Boolean = {
    this.f1.isDefined ||
      this.f2.isDefined ||
      this.f3.isDefined ||
      this.f4.isDefined
    // this is too-much of boilerplate
  }

  // This is something along the lines of what I want
  def hasAtleastOneDefinedField2: Boolean = {
    // this.getAllDeclaredFields.find(field => field.value.isDefined)
    ???
  }
}

是否可以在不使用反射的情况下做同样的事情？

Answer 1

不确定这能为您节省多少，但是:

  val hasAtLeastOneDefinedField = List(f1, f2, f3, ..., f35).exists { _.isDefined }

不要认为除了反射/宏之外还有其他方法。