Hello,

 

Me again and no it is not spamming, and I’m still drools newbie ;-)

 

I was facing a problem of infinite loop with one of my rule, I have solved it but I’m wondering if my solution is not too costful on a performance point of view.

So my question is really on the most efficient way of solving the infinite loop problem I’m gonna expose you right now.

 

First of all, a few words the problem I want to solve with Drools :

My company is a bank where traders are making deals on markets, these deals must be classified in book, this is what we call “booking process”.

Booking is done according to booking criteria : which trader has made the deal ? on which product ? etc …

A booking rule defines a set of criteria and the target book where the deal will classified.

 

The guilty rule’s job was to fill DealMatchingBookingRules with the booking rules applicable on a deal, (DealMatchingBookingRules references a unique deal).  

I have put below a corrected version by commenting the update($dealMatchingBookingRules) instruction of the RHS.

 

With update uncommented, the problem occurred when 2 booking rule were matching the same deal in here’s my understanding of the problem

Facts inserted in the session :

-         dmbr1 (instance of DealMatchingBookingRule) referencing a deal

-         br1 and br2 matching the deal referenced in dmr1

Results :

1. rule is activated with (dmbr1, br1), dmbr1 is updated
2. rule is activated with (dmbr1, br2), dmbr1 is updated - (dmbr1, br1) does not activate the rule because of no-loop rule attribute
3. rule is activated AGAIN with (dmbr1, br1), dmbr1 is updated : back to step 1
4. rule is activated AGAIN with (dmbr1, br2), dmbr1 is updated : back to step 2
5. infinite loop on step1 & step 2

 

I have fixed the problem by removing the call to update, but for the next steps of my process (not shown here) Drools need to aware of the modified DealMatchingBookingRules. I thus have written a rule which only update all DealMatchingBookingRules.

 

Is there a better way to solve this infinite loop ?

Feel free to make comments, I’m really open to any suggestion/enhancement.   

 

Regards,

 

Joël Costigliola

 

 

rule "Find matching level 1 booking rules by deal"

  salience 10

  no-loop

  ruleflow-group "Find level 1 matching booking rules by deal group"

 

  when

    $dealMatchingBookingRules : DealMatchingBookingRules($dealModel : deal, $dealProductRelatedIndexes : dealProductRelatedIndexes)

    $bookingRule : BTExecutionBookingRuleModel (

      priority == 1

      // when a criterion is not set, it is considered as satisfied.

      && (traderCriterion == null || $dealModel.trader == traderCriterion)

      && (portfolioCriterion == null || $dealModel.portfolio == portfolioCriterion)

      // when a product type criterion is set to unknown, it is considered as satisfied whatever deal product type is.

      && (productTypeStringCriterion == null || productTypeCriterion == ProductType.Unknown 

          || $dealModel.product.productType == productTypeCriterion) 

      && (listedIndexCriterion == null || $dealProductRelatedIndexes.relatedIndexes contains listedIndexCriterion)

    )

  then

    $dealMatchingBookingRules.addMatchingBookingRule($bookingRule);

    // update($dealMatchingBookingRules) : COMMENTED BECAUSE WAS CAUSING INFINITE LOOP !

end

 

// Does the job of update($dealMatchingBookingRules) but without INFINITE LOOP.

rule "Refresh facts in level 1 booking rule process"

  salience 5

  no-loop

  ruleflow-group "Refresh facts in level 1 booking rule process group"

 

  when

    $dealMatchingBookingRules : DealMatchingBookingRules()

  then

    update($dealMatchingBookingRules);

end