Hi Guys, I have the following situation while running a stateful session with Drools 4.0.7: - I want to test that a fact with a given state doesn't exist; - It works fine - At a certain point I have to retract all facts and reinsert them at the stateful session - some of them actually changed and I don't want to recreate the session b/c it's expensive - Again the fact that didn't exist when I first created the session still doesn't exist ** Problem: This time the rule that verified the non-existence is not fired because I didn't insert any fact that would retrigger it. Rule example: rule "022" when SiteLanguage(language : languageCode) t : SiteSpecialServiceType(type : specialServiceType) not SiteLanguageSpecialServiceType(specialServiceType == type, languageCode == language) then <<consequence>> end How could I solve or workaround that? Thanks in advance, Leo. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

wrote:

Hello, Regarding the session recreation, you're absolutely right, thanks! Anyway, I still have a problem and I believe it's more a design thing. Let me try to clarify it. I have different types of facts, let's say: * Types: FactA, FactB, FactC; * A stateful session with rules operating on them; * And a global variable, called output, which is a list of messages generated as consequences of those rules; * From time to time, I get notified that a fact of type FactA changed, then I have to: - retract all facts of type FactA from my working memory - reload them from the database (with java beans being created) - reinsert them in that stateful session Now, let's say FactA(1) indicates a fact of type FactA and id = 1. - Then, in the beginning, I insert FactA(1) and FactA(2) in my working memory and fire the rules. - I have several rules operating on different types of facts, but I'm interested in one rule in particular which operates against FactA and reads something like: rule "test non existence" when not FactA( id == 4 ) then output.add("there's no FactA id 4"); - This rule is fired and the message is added to my output object. Later on, I have a notification that a FactA has changed, then I: - retract all FactAs from my working memory - clear all FactA-related messages from my output object - reload FactAs (let's say now I have FactA(1), FactA(3), but NOT FactA(4)) - reinsert them in the WM - fire the rules The rule that checks that there's no FactA(4) doesn't refire. All other rules operating against FactA do, and since I had removed all FactA-related messages from my output object, this time I don't get the "there no FactA id 4" message in my output. It sounds like a situation for a stateless session, but I actually have several different rules, operating on different types of facts and don't want to refire all rules, just because a fact of type A changed. Maybe I should have an strategy of creating different sets of stateless sessions. I'm not sure. Advice is really welcome! Thanks again. Leo. 2009/11/17 Edson Tirelli <ed.tirelli(a)gmail.com&gt; > Leonardo, > > First, I believer there is a misconception in your reasoning: creating > sessions is supposed to be much much cheaper than retracting all facts. > Creating a rulebase is heavier, because it requires compilation, but > creating a session is supposed to be very light by design. So, first thing > you should do is change that. > > Regarding your question, if you insert: > > > SiteLanguage(language : languageCode) > t : SiteSpecialServiceType(type : specialServiceType) > > The rule will activate and fire. If you don't, then the rule will not > match. That is how it is supposed to work. > > Edson > > 2009/11/17 Leonardo Gomes <leonardo.f.gomes(a)gmail.com&gt; > >> Hi Guys, >> >> I have the following situation while running a stateful session with >> Drools 4.0.7: >> >> - I want to test that a fact with a given state doesn't exist; >> - It works fine >> - At a certain point I have to retract all facts and reinsert them at the >> stateful session - some of them actually changed and I don't want to >> recreate the session b/c it's expensive >> - Again the fact that didn't exist when I first created the session still >> doesn't exist >> >> ** Problem: This time the rule that verified the non-existence is not >> fired because I didn't insert any fact that would retrigger it. >> >> Rule example: >> >> rule "022" >> >> when >> >> SiteLanguage(language : languageCode) >> t : SiteSpecialServiceType(type : specialServiceType) >> not SiteLanguageSpecialServiceType(specialServiceType == type, >> languageCode == language) >> then >> <<consequence>> >> end >> >> How could I solve or workaround that? >> >> >> Thanks in advance, >> Leo. >> _______________________________________________ >> rules-users mailing list >> rules-users(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/rules-users >> >> > > > -- > Edson Tirelli > JBoss Drools Core Development > JBoss by Red Hat @ www.jboss.com > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > >

2009/11/26 Leonardo Gomes <leonardo.f.gomes(a)gmail.com&gt; > > > On Tue, Nov 24, 2009 at 10:42 PM, Leonardo Gomes < > leonardo.f.gomes(a)gmail.com&gt; wrote: > >> H >> >> Now, let's say FactA(1) indicates a fact of type FactA and id = 1. >> >> - Then, in the beginning, I insert FactA(1) and FactA(2) in my working >> memory and fire the rules. >> >> rule "test non existence" >> when >> not FactA( id == 4 ) >> then >> output.add("there's no FactA id 4"); >> >> - This rule is fired and the message is added to my output object. >> >> Later on, I have a notification that a FactA has changed, then I: >> - retract all FactAs from my working memory >> - clear all FactA-related messages from my output object >> - reload FactAs (let's say now I have FactA(1), FactA(3), but NOT >> FactA(4)) >> - reinsert them in the WM >> - fire the rules >> >> The rule that checks that there's no FactA(4) doesn't refire. >> > Why should it? The truth of the non-existance of FactA(4) has been established, and this truth never changed, certainly not by removing any FactA(n) and also not by inserting any FactA(x) with x!= 4. As a solution, you could - establish an explicit fact, asserted in rule "test non existence" and retracted by a rule checking the negated condition; - add a Trigger fact to rule "test non existence" which you modify after each reload of the FactA set - do something else which I'm not clever enough to think about at the moment -W