Re: [rules-users] [planner] Drools planner & Scala => Solution.getScore():Score<?>
Hello,
Michael Neale (the drools guvnor guy) is also using Scala and Drools
Planner together. His code is at github.
I was looking for his account but a search
for "Neale" only finds some comments in BMW's repos. You know what his
username is?
If the issue still makes sense, feel free to open an issue for the
org.drools.planner.core.solution.Solution#getScore():Score<?>
discussion (and copy this part of the discussion).
Why should it be Score<?> and not
2) Score<S extends Score>
3) or Score<<S extends Score<S extends Score> >> ?
Well in case
2) Scala would still complain about a missing type parameter for the inner Score. Same for
3, it could go on forever. So for recursive type parameters you need to stop at some point
and put in a wildcard (? in java or _ in scala). Score<?> and Score have the same
meaning in Java (they both mean any Score), the only difference is that one works, the
other not in Scala ;). And for the use in the Solution interface I think it's write -
the get/set method store any score, you don't know which one.
4) Or maybe it should be, just like EnumSet?
class Solution<S extends Score> {
public S getScore()
}
This would of course work also, but it's a much bigger refactoring. And it
could have some viral consequences. Score<?> instead of Score is just a drop-in
replacement :).
--
Adam Warski
http://www.warski.org
http://www.softwaremill.eu