Small utility to clean up longish stacktraces. All comments how to make it more generic warmly welcome.

StackTraceHelper.scala

object StackTraceHelper
{

  def retainWithBorder [T] (items:    Seq[T],
                            valuable: (T => Boolean)): Seq[T] =
  {
    if (items.size < 3) return items

    val retained = for
    {
      slice <- items.sliding (3)
      if slice.exists (valuable)
    } yield slice (1)

    Seq(items.head) ++ retained ++ Seq(items.last)
  }

  def clean (exception: Throwable, valuable: StackTraceElement => Boolean) =
  {
    val originalTrace = exception.getStackTrace
    val filteredStack = retainWithBorder (originalTrace, valuable).toArray
    exception.setStackTrace (filteredStack)
  }

}