how to translate contrants "drools" into "dmn" (Decision Model and Notation)

Question

rule "room conflict"
    when
        Lesson($id : id, $timeslot : timeslot , $room : room)
        Lesson(id != $id, timeslot == $timeslot , room == $room)
    then
        scoreHolder.addHardConstraintMatch(kcontext, -1);
end

Answer 1

You don't.

As Lukáš indicates in the comments, OptaPlanner has no DMN support.

On the other hand, regular open-source Drools does have DMN support, but no built-in concept of constraints.