Thanks. Works like a champ. I had a feeling that it was something
simple.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
On Behalf Of [EMAIL PROTECTED]
Sent: Wednesday, August 31, 2005 1:31 PM
To: jess-users@sandia.gov
Subject: Re: JESS: Modifying JavaBeans
Hi Scott,
Rules only fire during a call to run(). Your call to run() returns
immediately because when you call it, there are no rules eligible to
fire yet. Then you make some changes to the fact, and the
PropertyChangeEvents update the working memory, but you never call
run() again, so even when it is activated, the rule never fires.
You could call run() in your for loop, and then the rule would fire and
update the slot as expected. Note that it makes sense for this rule to
fire only once -- no reason to fire once the qualRng slot is TRUE, so
you might write the pattern like this:
(defrule dummy-range-doctrine
;; set qualRng to true if trk is in range
?fact <- (testTrkClass (range ?x&:(<= ?x 20)) (qualRng ~TRUE))
=>
(modify ?fact (qualRng TRUE)))
I think Krasnigor, Scott L (N-AST) wrote:
> Sorry to bother everyone. I am trying to play around with JESS
> embedded in Java to get an understanding of JESS. I created a simple
> Java bean which contains two properties: range and qualRng. I create
> the fact within Jess utilizing defclass and definstance. Executing
> engine.facts() shows that the fact has been created in Jess's memory
> with the appropriate slots. I created a simple rule to check to see if
> range is below 20, if true, modify the qualRng slot to TRUE. I added
> code to
> main() decrement the initial value of range in order to fire the rule.
> Watching the results shows that the range slot decrements properly and
> the rule fires, but the qualRng field never gets updated to show TRUE.
> I am sure it is something simple, but I just don't see the problem.
> I've modified the RHS of the rule with all the different iterations I
> could think of but to no avail. The code is listed below (minus the
> java bean class). Thanks for your assistance.
>
> import jess.*;
>
> public class testFacts
> {
> public static void main(String[] args)
> {
> Value fact;
> try
> {
> Rete engine = new Rete();
> engine.watchAll();
>
> engine.defclass("testTrkClass", "testTrack",
null);
> testTrack trkOne = new testTrack(30, 45, 5);
> fact = engine.definstance("testTrkClass",
> trkOne, true);
>
> // Load rules clip file
> engine.executeCommand("(batch testTrk.clp)");
> engine.run();
>
> // change range until it triggers a dummy doct
rule
>
> int i;
> for(i = trkOne.getRange(); i > 5; i--)
> {
> trkOne.setRange(i);
> try
> {
> Thread.sleep(500);
> }
> catch (InterruptedException ie){}
> }
> }
> catch (JessException je)
> {
> System.out.print("An error occurred at line " +
> je.getLineNumber());
> System.out.println(" which looks like " +
je.getProgramText());
> System.out.println("Message: " +
> je.getMessage());
> }
> }
>
> }
>
> The clp file:
>
> (defrule dummy-range-doctrine
> ;; set qualRng to true if trk is in range
> ?fact <- (testTrkClass (range ?x&:(<= ?x 20)))
> =>
> (modify ?fact (qualRng TRUE)))
>
>
>
> Scott L. Krasnigor
> Principal Engineer/Scientist
> Atlantic Science & Technology
> Lockheed Martin - MS2
> ' 856-359-3094
> * [EMAIL PROTECTED]
> * 770-2
>
---------------------------------------------------------
Ernest Friedman-Hill
Advanced Software Research Phone: (925) 294-2154
Sandia National Labs FAX: (925) 294-2234
PO Box 969, MS 9012 [EMAIL PROTECTED]
Livermore, CA 94550 http://herzberg.ca.sandia.gov
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