After talking to Stuart and Jason and Dave, along with reading the
various JRules papers, it seems there are a few concepts of time:
1) Time as a condition event:
when:
cinderalla.getLocation() == ROYAL_PALACE;
clock.strikesMidnight();
Rudimentary speaking, this could be accomplished by asserting
a 'now' Date object into the working memory every minute,
but that's a woefully bad implementation. I think a syntax
adjustment for wall-clock time would be required:
when at midnight:
cinderalla.getLocation() == ROYAL_PALACE;
That'd keep us from checking any part of the rule unless
the time part is matched.
2) Time as how long a condition should hold:
when:
msg.hasBeenSent();
after 6 hours:
! msg.hasBeenRepliedTo();
So, match all of the {when}, and then, evaluate the {after}
upon time expiration. While this could be modelled using
the (1) case above, and two rules, I think additional syntax
to make it simple to do it in one rule would be nice.
Here's the 2-rule version:
rule #1
-------
when:
msg.hasBeenSent();
then:
assertObject( new ReplyWaiter( msg ) );
rule #2
-------
when at 4pm:
! replyWaiter.receivedReply()
3) Additionally, while waiting, we need to decide
(probably on a rule-by-rule basis) if we watch the conditions
during the interval, and cacel if the conditions become
false any time during the interval; or if we only care
about the conditions at interval expiration, not worrying
if their truth value changed many times during the interval.
-bob
_______________________________________________
drools-interest mailing list
[EMAIL PROTECTED]
https://lists.sourceforge.net/lists/listinfo/drools-interest
