[rules-users] "Exists" CE behaviour
Chivotario Martin
chivotario at gmail.com
Mon Jul 13 06:59:14 EDT 2009
Hi Wolfgang,
I do not know if i can use the issue tracker to post this as an issue, as i
don't know if i'm allowed to do so, and also if this is officially, really a
bug or the expected behaviour :) .
However i left a complete piece of code showing the behaviour i'm getting :
*RuleTester.java*
package org.drools.test;
import org.drools.KnowledgeBase;
import org.drools.KnowledgeBaseConfiguration;
import org.drools.KnowledgeBaseFactory;
import org.drools.RuleBaseConfiguration;
import org.drools.builder.KnowledgeBuilder;
import org.drools.builder.KnowledgeBuilderFactory;
import org.drools.builder.ResourceType;
import org.drools.io.ResourceFactory;
import org.drools.runtime.StatefulKnowledgeSession;
public class RuleTester {
private static final int MAX_EVENTS = 5;
public class Foo { }
public void test() {
KnowledgeBaseConfiguration config =
KnowledgeBaseFactory.newKnowledgeBaseConfiguration();
((RuleBaseConfiguration)config).setRuleBaseUpdateHandler( null );
KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(config);
StatefulKnowledgeSession session =
kbase.newStatefulKnowledgeSession();
for (int i=0; i<MAX_EVENTS; i++) {
session.insert(new Foo());
}
for (int i=1; i<3; i++) {
KnowledgeBuilder kbuilder =
KnowledgeBuilderFactory.newKnowledgeBuilder();
kbuilder.add( ResourceFactory.newClassPathResource(
"test"+i+".drl" ), ResourceType.DRL);
if( kbuilder.hasErrors() ) {
System.out.println( kbuilder.getErrors() );
return;
}
kbase.addKnowledgePackages( kbuilder.getKnowledgePackages() );
int fireCount = session.fireAllRules();
System.out.println("Test"+i+".drl , number of rules fired =
"+fireCount);
}
session.dispose();
}
public static void main(String[] args) {
RuleTester tester = new RuleTester();
tester.test();
}
}
*test1.drl*
import org.drools.test.RuleTester.Foo;
rule "notNotRule"
when
exists ( Foo() );
then
System.out.println("Rule fired...");
end
*test2.drl*
import org.drools.test.RuleTester.Foo;
rule "notNotRule"
when
not ( not ( Foo() ) );
then
System.out.println("Rule fired...");
end
Using Drools 5.0.1-Final , the expected output would be :
> Test1.drl , number of rules fired = 0
> Rule fired...
> Test2.drl , number of rules fired = 1
If someone allows me to open this a a JIRA i would try to understand how to
use it :D and would do so.
Regards,
Manuel.
2009/7/13 Wolfgang Laun <wolfgang.laun at gmail.com>
> Quite right, since not(not(Foo())) is equivalent to exists(Foo()).
>
> Martin, would you please submit a JIRA?
>
> -W
>
>
> On 7/13/09, Chivotario Martin <chivotario at gmail.com> wrote:
> > Hi Visu,
> >
> > My understanding (also tested) is that activations are created no matter
> the
> > knowledge base has the rule packages loaded
> > before or after the working memory is filled with facts, but the
> execution
> > of the rules happens automatically if the working memory is filled in
> > advance.Setting the RuleBaseUpdateHandler to null, prevents the execution
> of
> > the rules but keeps activations to be created when adding a rule to the
> > kbase.
> > In this case, it seems the exists CE only creates activations if the
> rules
> > are loaded before the working memory is populated.
> > But this doesn't happen if i change the statement :
> >
> > exists ( Foo() ) --> not ( not ( Foo() ) )
> >
> > In this case, activations are created no matter whether the kbase is
> empty
> > or not before populating the WM.
> >
> >
> >
> >
> > 2009/7/13 Viswanathan Nageswaran <visu.nageswaran at in.ibm.com>
> >
> > > Chivotario,
> > >
> > > >From what I understand, the activation of rules happen as facts are
> > > inserted into the working memory; hence it is important for the session
> to
> > > be begun against a knowledge base that has the rule packages loaded
> before
> > > the facts are inserted.
> > >
> > > -Visu
> > >
> > >
> > >
> > >
> > > Chivotario Martin
> > > <chivotario at gmail
> > > .com>
> To
> > > Sent by: rules-users at lists.jboss.org
> > > rules-users-bounc
> cc
> > > es at lists.jboss.or
> > > g
> Subject
> > > [rules-users] "Exists" CE
> behaviour
> > >
> > > 13/07/2009 14:11
> > >
> > >
> > > Please respond to
> > > Rules Users List
> > > <rules-users at list
> > > s.jboss.org>
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > Hi ,
> > >
> > > I'm trying to use the Exists keyword within my rules with the following
> > > snippet :
> > >
> > > // Create a session
> > > KnowledgeBaseConfiguration config =
> > >
> > KnowledgeBaseFactory.newKnowledgeBaseConfiguration();
> > >
> > ((RuleBaseConfiguration)config).setRuleBaseUpdateHandler(
> > null ); *
> > > KnowledgeBase kbase =
> > KnowledgeBaseFactory.newKnowledgeBase(config);
> > > StatefulKnowledgeSession session =
> > kbase.newStatefulKnowledgeSession();
> > >
> > > // Add some objects
> > > for (int i=0; i<5; i++) {
> > > }
> > >
> > >
> > > // Add a DRL to the kbase
> > > KnowledgeBuilder kbuilder =
> > KnowledgeBuilderFactory.newKnowledgeBuilder();
> > > kbuilder.add( ResourceFactory.newClassPathResource(
> > "test/existsTest.drl"
> > > ), ResourceType.DRL);
> > > kbase.addKnowledgePackages(
> > kbuilder.getKnowledgePackages() );
> > >
> > > // Fire rules
> > > int fireCount = session.fireAllRules();
> > >
> > >
> > > existsTest.drl :
> > >
> > > rule "existsTest"
> > > ( Foo() ) ); (2)
> > >
> > > end
> > >
> > > When launched , the rule is not fired (no messages , fireCount 0), but
> it
> > > is when changing
> > > exists with a double not condition (2).
> > > If the working memory is populated after adding the rules file, the
> exists
> > > CE works as expected.
> > > * I've used no RuleBaseUpdateHandler preventing automatic activations
> to
> > be
> > > executed so fireAllRules can be used to get the fireCount, but
> commenting
> > > this line out doesn't change the results.
> > >
> > > Probably i'm doing something wrong so a little help would be very
> > > appreciated.
> > >
> > > Regards,
> > > Manuel.
> > > _______________________________________________
> > > rules-users mailing list
> > > rules-users at lists.jboss.org
> > > https://lists.jboss.org/mailman/listinfo/rules-users
> > >
> > >
> > >
> > > _______________________________________________
> > > rules-users mailing list
> > > rules-users at lists.jboss.org
> > > https://lists.jboss.org/mailman/listinfo/rules-users
> > >
> >
> >
> > _______________________________________________
> > rules-users mailing list
> > rules-users at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/rules-users
> >
> >
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