Re: [rules-users] Implementing Refraction with Drools
You can improve your example by using an agenda listener to remove Activations once they
are cancelled, this way you avoid a memory leak.
Further you can use annotations, to control this per rule.
rule xxx @repeatable(true) when
then end
then in your filter you can check rule.getMetaData( "repeatable" )
We aren't going to add this to Drools right now, but it certainly is a useful example
for people.
We'll be reviewing execution control during the 6.x series, and we'll look at it
then. I believe that you can have different types of repeability, and I'd like to look
at rising falling edges. It's important that you don't add features one at a time,
as one might make another impossible. So these things must be look at, as a whole, and
planned out.
Mark
On 23 Jan 2013, at 00:39, magaram <magaram(a)deltadentalmi.com> wrote:
Thanks for the clarifications Mark and Wolfgang. I wanted to share
some
additional data.
I was trying to reproduce the same behavior that ILOG JRules exhibits by
default for refraction.
My experiment with no-loop and lock-on-active did not work when I compared
against my baseline results with JRules. However, the interesting part was
when I ratified the agenda filter as follows (wrong and hacky as it is) -
removed the encounteredActivations.remove(act) before returning false, it
matched the ILOG baselines exactly. I ran through 46 test cases as part of
my baseline, all of which have several looping opportunities single and
complex. My earlier agenda filter implementation that I posted earlier did
not yield identical results with the JRules baseline.
It seems this logic for refraction seems to mimic JRules refraction
behavior. From commercial use case perspective refraction/repeatability
control is important. ILOG implements refraction out of the box as part of
conflict resolution. However they offer up a antecedent directive called
refresh (in lieu of update) that overrides refraction...
import java.util.ArrayList;
import java.util.List;
import org.drools.runtime.rule.Activation;
import org.drools.runtime.rule.AgendaFilter;
/**
* This custom agenda filter injects refraction behavior into the rule
engine
* @author Mukundan Agaram
*
*/
public class RefractionAgendaFilter implements AgendaFilter {
private List<Activation> encounteredActivations = new
ArrayList<Activation>();
@Override
public boolean accept(Activation act)
{
//Check for a Refraction
if (encounteredActivations.contains(act))
{
return false;
}
//Otherwise add the rule to check for potential refractions in the future
encounteredActivations.add(act);
//select the rule to be part of the agenda
return true;
}
}
--
View this message in context:
http://drools.46999.n3.nabble.com/Implementing-Refraction-with-Drools-tp4...
Sent from the Drools: User forum mailing list archive at Nabble.com.
_______________________________________________
rules-users mailing list
rules-users(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users