Scala：子类化具有多个构造函数的Java类？

Question

我正在尝试扩展 Java Exception 类，但结果非常丑陋和笨拙。 所以，我不确定我是否走在正确的轨道上。有更好的方法吗？

class ParentError(_d: Double, msg: String, cause: Throwable)
      extends Exception(msg: String, cause: Throwable) {
  def this() = this(0, null, null)
  def this(d: Double) = this(d, null, null)
  def this(msg: String) = this(0, msg, null)
  def this(msg: String, cause: Throwable) = this(0, msg, cause)
  def this(cause: Throwable) = this(0, null, cause)
  def i = _d
}

case class ChildError(_b: Boolean, _i: Double, msg: String, cause: Throwable)
      extends ParentError(_i: Double, msg: String, cause: Throwable) {
  def this(b: Boolean) = this(b, 0, null, null)
  def this(msg: String) = this(false, 0, msg, null)
  def this(msg: String, cause: Throwable) = this(false, 0, msg, cause)
  def this(cause: Throwable) = this(false, 0, null, cause)
  def b = _b
}

注意：我看到了In Scala, how can I subclass a Java class with multiple constructors?，但我认为这不是我要找的。谢谢

Answer 1

使用默认值，例如：

class ParentError(i: Double = 0, msg: String = null, cause: Throwable = null)
      extends Exception(msg: String, cause: Throwable) {
      ⋮
}