In Scala v 2.7.7
I have a file with
class Something[T] extends Other
object Something extends OtherConstructor[Something]
This throws the error:
class Something takes type parameters
object Something extends OtherConstructor[Something] {
However, I can't do this
object Something[T] extends OtherConstructor[Something[T]]
It throws an error:
error: ';' expected but '[' found.
Is it possible to send type parameters to object? Or should I change and simply use Otherconstructor
You could use:
object Something extends OtherConstructor[Something[_]]
You will of course be restricted by having an existential type with no upper bound in place instead of a concrete type. This solution may not make sense and you might need one object per concrete type T
, for those T's which you care about, e.g.
object StringSomething extends OtherConstructor[Something[String]]
But then this has the (possible) disadvantage that StringSomething
is not the companion object of Something
.
However, my advice would be don't start messing about designing generic APIs (especially self-referential ones like the above) unless you really, really know what you are doing. It will almost certainly end in tears and there are plenty of CORE Java API's which are terrible because of the way generics have been added (the RowSorter
API on JTable
being one example)