Re: [rules-dev] modify (expr) catch 22
On 08/04/2011 12:39, Geoffrey De Smet wrote:
Related to the modify expression,
I 've always wondered about this code:
rule "MyRule"
when
$p : Person(name = "Yoda")
then
modify ($p) {
setAge(300)
}
end
Doesn't this create an infinite loop? (In my experience it does or at
least it takes a lot longer)
Because the modify ($p) schedules any rule using a Person back on the
agenda to be re-evaluated,
so also that rule, which is evaluated and executed again, modifying $p
again, ... hence the infinite loop?
It would, unless you have slot specific - which
Jess does. Slot specific
is something I really want to add, I think it will resolve a lot of
recursion problems and make Drools a lot easier to use. I took the slot
specific problem and genericsed it further for "slot listeners". I
discussed this here:
http://blog.athico.com/2010/07/slot-specific-and-refraction.html. I
think Laune added some refinements to this in a mailing list entry
somewhere.
Mark