Yes thats a good point, if the engine assertions recurse indefinitely the rules will never be removed or added. The FireAllRulesRuleBaseUpdateListener is pluggable, see the RuleBaseConfiguration so you replace that with alternative logic. We will look to see if there is a better way for the next major release.

Mark

Remi Barraquand wrote:

Issue:

By looking in the Drools source code i found something interesting...

When you call session.getRuleBase().addPackage(yourPackage) event of the
type AfterPackageAddedEvent are sent to all RuleBaseListener of the
RuleBase. It appear that one of this listener is added by default, which is
: org.drools.base.FireAllRulesRuleBaseUpdateListener.

This listener when receiving an event of this type, call the following
method:

public void beforeRuleBaseUnlocked(BeforeRuleBaseUnlockedEvent event) {
    if ( session.getRuleBase().getAdditionsSinceLock() > 0 ) {
        session.fireAllRules();
    }
} 

and so call fireAllRules(); !! this imply that if  you have cycling rules
inside you rule package you will never leave the 
session.getRuleBase().addPackage(yourPackage) call.....

Solution:

- One solution would be to remove this listener by defaut and add one with
an overloading of the beforeRuleBaseUnlocked method.

- A better solution i think, would be to be able to set a default fireLimit
option on session, so a call to fireAllRule would use this defaultFireLimit.
What do you think ?

- is there a better solution ? do i miss something ?

Give me your point on it,

Rémi


Remi Barraquand wrote:

Hi there,

I'm developing a library that uses drools as a REAL-TIME rule engine. What
i'm a doing right now is to have a thread that wakes up each 100ms and do
a fireAllRules(1000).

I need to be able to load Facts and Rules on the fly, even after the
statefullsession is created. The problem is that when i add a new
RulePackage to the current rulebase's session, all the rules inside this
package are evaluated ! and so i never exit from this addPackage function
!!

System.out.println("Start loading rules");

// build builder package configuration
PackageBuilderConfiguration conf = new PackageBuilderConfiguration();
conf.setClassLoader(factionary);

// Load file
File file = new File(chooser.getSelectedFile().getPath());
PackageBuilder builder = new PackageBuilder(conf);

builder.addPackageFromDrl(new FileReader(file));

// Load package to session
session.getRuleBase().addPackage(builder.getPackage()); // GET STUCK HERE
!!!!!!!!!!!

// Print success
jTextArea2.append(chooser.getSelectedFile().getPath()+"\n");
jTextArea2.setCaretPosition(jTextArea1.getDocument().getLength());

System.out.println("Done loading rules");

What i want is just to add the rules from the package that's all.... Since
i've a thread that call fireAllRules(1000) each 100ms the rules will get
proceced next time :)

Do you have any idea of how to do that ?

Thanks.

Barraquand Rémi

Issue

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________________________________________
Rémi Barraquand, PhD I.N.P.G
Projet PRIMA - Laboratoire  LIG
INRIA Grenoble Rhones-Alpes Research Centre
655 Ave de l'Europe
38330 Montbonnot, France