Custom Exception in scala

Question

how can i create custom exceptions in Scala extending Exception class and throw them when exception occurs as well as catch them.

example in java :

Answer 1

In order to reflect all the original constructors from Exception I'd implement a custom exception with the following pattern:

class CustomException(msg: String) extends Exception(msg) {
  def this(msg: String, cause: Throwable) = {
    this(msg)
    initCause(cause)
  }

  def this(cause: Throwable) = {
    this(Option(cause).map(_.toString).orNull)
    initCause(cause)
  }

  def this() = {
    this(null: String)
  }
}

This can be also achieved with a trait as mentioned in previous answer. I'd just not create individual classes in this case:

trait SomeException { self: Throwable =>
  def someDetail: SomeDetail
}

then, when throwing:

throw new Exception(...) with SomeException {
  override val someDetail = ...
}

and when matching:

try {
  ...
} catch {
  case ex: Throwable with SomeException =>
    ex.getCause
    ex.getMessage
    ex.someDetail
}

The advantage here is that you are not sticking to any particular constructor of the parent exception.

something more or less like that.