from recursive method to iterator in scala

def yieldClass2(clazz:Class[_]): Iterator[Class[_]] = {
  import scala.collection.{Iterator => I}
  clazz match {
    case null => I.empty
    case _ =>
      val interfaces = clazz.getInterfaces map { yieldClass2 } reduceLeft (_ ++ _)
      I.single(clazz) ++ yieldClass2(clazz.getSuperclass) ++ interfaces
  }
}