如何捕获异常并引发其他异常

Question

I have a for loop that I'm expecting an IndexOutOfBoundsException on. I want this particular exception, when raised, to throw a custom exception. I currently have this:

try {
  for (i <- 0 until end) {
    // do something
  }
} catch {
  case e: IndexOutOfBoundsException =>
    throw CustomException("Raised expected IndexOutOfBoundsException", e)
}

However, when the above snippet is run, the compiler tells me that an IndexOutOfBoundsException was raised and not my custom exception. What would I have to do to raise my custom exception?

The custom exception is defined as:

case class CustomException(private val message: String = "", private val cause: Throwable = None.orNull) extends Exception(message, cause)

Answer 1

Use Try and recoverWith . recoverWith handles the failure case and further tries to propagate the success or failure of new Try computation.

Try {
  for (i <- 0 until end) {
    // do something
  }
}.recoverWith { case e: IndexOutOfBoundsException =>
 Try.failed(CustomException("Raised expected IndexOutOfBoundsException", e))
}