KIE Community

The BOF was a success and as promised, I ‘ve posted the slides online:

• Javapolis 2007 slides and speaker notes (ODF)
• Javapolis 2007 slides and speaker notes (PDF)

People asked a bunch of interesting questions afterwards.
One question I felt I left a bit unanswered: how do you weigh your constraints in DRL? So, here’s a code example that should answer that question too:

rule "twoExamsInARow"
  when
    // ...
  then
    insertLogical(new IntConstraintOccurrence(
        "twoExamsInARow",
        10, // weight
        $leftExam, $rightExam));
end

rule "twoExamsInADay"
  when
    // ...
  then
    insertLogical(new IntConstraintOccurrence(
        "twoExamsInADay",
        1, // weight
        $leftExam, $rightExam));
end

rule "softConstraintsBroken"
  when
    $total : Double() from accumulate(
      IntConstraintOccurrence($weight : weight),
      sum($weight)
    );
  then
    scoreCalculator.setSoftConstraintsBroken($total.intValue());
end

So the 2 in a row constraint is 10 times heavier than the 2 in a day constraint.