[rules-users] Calculate the sum of "price" attribute from many facts.

Dear all, In my problem, I have to calculate the sum of "price" field from many Drink facts. Here is the code I have: when Likes($nameS : name, $drinkS : drinkSpeciality) Drink(speciality == $drinkS, $price : price) then //calculate something like: totalPrice+=$price Inspired from what Edson said, I've defined an Accumulator class and I solve the problem: when $a:Accumulator() Likes($nameS : name, $drinkS : drinkSpeciality) Drink($speciality : speciality ->($speciality == $drinkS), $price : price) then $a.incrementDrinksPrice($price.intValue()); In this context, my questions are: 1) Is there another appropriate solution to calculate the sum of prices? 2) What is the use of global variables? (because I think I missunderstood their meanings). Can I solve my problem using a global variable like an accumulator, knowing that a global variable is acting like a static variable? Best regards, Oana. Edson Tirelli <tirelli(a)post.com&gt; wrote: Jeevan, sorry, I missed your e-mail in the limbo. Just create a class or an attribute to be your accumulator... For instance, if you create a "branchCounter" attribute in the Tree object, you can do that: rule "Count branches" salience 10 when $t : Tree() Branch( tree == $t ) then $t.incrementBranchCounter(); modify( $t ); end rule "Check branch count" salience 0 when $t : Tree( branchCounter > 100 ) then // do something end The only trick is the salience. The first rule must have a higher salience in order to only fire the second rule after all branches are counted. Yes, in trunk you could do better with "accumulate" or "collect". For your case, "collect" would be simpler: rule "Check branches" when $t : Tree() $branches : ArrayList( size > 100 ) from collect( Branch( tree == $t ) ) then // do something end []s Edson Jeevan Tambuluri wrote: -- Edson Tirelli Software Engineer - JBoss Rules Core Developer Office: +55 11 3124-6000 Mobile: +55 11 9218-4151 JBoss, a division of Red Hat @ www.jboss.com _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users --------------------------------- Sucker-punch spam with award-winning protection. Try the free Yahoo! Mail Beta.