[rules-users] RE: Why not retracting?

[Grimshaw, Jeffrey]

Hi Michael.  I've only been using JBoss Rules for about 2 weeks, so keep
that in mind when reading my reply.  
 
The way I understand it works is that facts are evaluated against the
LHS of all the rules in the ruleset as they are asserted.  That is, when
a fact is added to the WorkingMemory, the engine determines which rules
apply to that fact.  You may expect that evaluation to take place when
the rules are "run".  This may have something to do with the behavior
you are seeing.
 
For more info on what I'm talking about, see section 1.6.4.2 of the user
docs.  
http://labs.jboss.com/file-access/default/members/jbossrules/freezone/do
cs/3.0.5/html/index.html
 
Cheers,

--Jeff 

 

________________________________

From: rules-users-bounces at lists.jboss.org
[mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Anstis,
Michael (M.)
Sent: Friday, January 26, 2007 8:08 AM
To: Rules Users List
Subject: [rules-users] RE: Why not retracting?



By way of an update; if the retraction is made within a different Agenda
Group the rules work as expected. 

However the problem of the retraction having no obvious affect when
operated within the same Agenda Group remains. 

Is this a bug? 

	_____________________________________________ 
	From:   Anstis, Michael (M.)  
	Sent:   26 January 2007 11:32 
	To:     'Rules Users List' 
	Subject:        Why not retracting? 

	Hello, 

	I have the following rules; one removes "Prices" that do not
have the required "Economic Level" from working memory, the other
calculates a "Costs":-

		rule "Cost - remove prices that do not have the required
'Economic Level'" 
		agenda-group "stamping-costs" 
		//salience 1 
		when 
		        p : Price ( economicLevel != (
Utilities.makeDate(1, 1, 2007) ) ) 
		then 
		        System.out.println("Retracting "+p.toString()); 
		        retract(p); 
		end 

		rule "Cost - calculate cost for 'Stamping process' on a
process" 
		agenda-group "stamping-costs" 
		//salience 2 
		when 
		        r : ResourceEntry ( m : machine ) 
		        //p : Price ( economicLevel == (
Utilities.makeDate(1, 1, 2007) ), machine == ( m ) ) 
		        p : Price ( machine == ( m ) ) 
		then 
		        Cost cost = new Cost(r, p); 
		        cost.setCost((float) (r.getUsage() *
p.getRate())); 
		        assert(cost); 
		end 

	The problem is that the "Cost" rule still works upon ALL
"Prices" (even those with an incorrect "Economic Level"). 

	If I change the line in the "Cost" rule to also check the
"Economic Level" the rules work as expected (i.e. "Costs" are only
calculated using "Prices" with an "Economic Level" of 01/01/2007).

	I've tried using "salience" levels too (as commented in the
above Rules) but this doesn't have any effect either. 

	What am I doing wrong? 

	Cheers, 

	Mike 

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