RE: [rules-users] Help Needed
Thanks a lot Steve it worked fine. I need some more information on Agenda Groups. How we can use and which scenario we can issue? Thanks Regards Shilpa -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Steven Williams Sent: Tuesday, February 13, 2007 9:21 AM To: Rules Users List Subject: Re: [rules-users] Help Needed Hi Shilpa, You can pass your DAOs (or any other object) into the working memory as globals and then use them in the consequence of your rules. cheers Steve On 2/13/07, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: Hi, I am using Drools 3.0 in our business logic. I need help in the below situation I will take the records from the database on daily basis and each record is fact in the rule engine I will check the fact against some constant value; if it satisfies the condition then I need to update one field in the database. I am using Ibatis as DAO framework. How I can connect to database in .drl file? Please help me. Thanks Regards Shilpa The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments. WARNING: Computer viruses can be transmitted via email. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email. www.wipro.com ___ rules-users mailing list rules-users@lists.jboss.org mailto:rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users -- Steven Williams Supervising Consultant Object Consulting Office: 8615 4500 Mob: 0439 898 668 Fax: 8615 4501 [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] www.objectconsulting.com.au consulting | development | training | support our experience makes the difference The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments. WARNING: Computer viruses can be transmitted via email. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email. www.wipro.com___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] decision tables and 'default' or 'else' conditions
Hi Edson, I've abstracted our use case since I gather you don't understand the dutch legal system. :-) Given a decision table like this ( I hope you are able to read the HTML post correctly) I A p II B q III C r IV D s none of the above E t F u none of the above v we are looking for a keyword that has a meaning similar to none of the above The point of this functionality for us is that the business analyst is only interested in the values I to IV but possibly there are 20 or more values. The semantics that we need would be such that this would translate into the following rules I and A then p II and B then q III and C then r IV and D then s not(I) and not(II) and not(III) and not(IV) and E then t not(I) and not(II) and not(III) and not(IV) and F then u not(I) and not(II) and not(III) and not(IV) and not(A) and not(B) and not(C) and not(D) then v I hope this answers your questions. We will need this functionality pretty soon. Can you give an indication what the priority is for you guys for this functionality? groetjes uit Nederland, Joost 2007/2/7, Edson Tirelli [EMAIL PROTECTED]: Joost, Unfortunatelly, there is no feature implemented for that. But we are discussing, specially the semantics we want to define to such statements ( we call them else and otherwise ). If you have a real use case and you can describe it for us, it may help on deciding which way to go, and at the same time fullfil your needs in the future. Our biggest questions are: * should the else/otherwise part be fired only once if no rule is triggered? or should it fire for each tuple that does not trigger previous rules? What if rules in the otherwise group use different tuples to activate? * should else/otherwise apply to the whole LHS of the rules? Or should there be a way to specify only part of the LHS (like a tag)? Input welcome. Edson Joost de Vries wrote: Hi, We're using excel decision tables to specify our business rules. In one column we enumerate several condition values and describe a specific effect. We'd like to offer business analysts te possibility of describing succinctly what the effect is 'for all other values'. That could be described as an 'else' or 'default' rule. In other words; we don't want to burden business analysts with the necessity to enumerate all other values. What is the right way to do that? Thanks for you help. groetjes, Joost ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users -- 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@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users -- Joost de Vries 06 22375323 werk: [EMAIL PROTECTED] privé: [EMAIL PROTECTED] ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] decision tables and 'default' or 'else' conditions
Ok, I think that HTML tables get mangled. I'll mail it to you directly. 2007/2/13, Joost de Vries [EMAIL PROTECTED]: Hi Edson, I've abstracted our use case since I gather you don't understand the dutch legal system. :-) Given a decision table like this ( I hope you are able to read the HTML post correctly) I A p II B q III C r IV D s none of the above E t F u none of the above v we are looking for a keyword that has a meaning similar to none of the above The point of this functionality for us is that the business analyst is only interested in the values I to IV but possibly there are 20 or more values. The semantics that we need would be such that this would translate into the following rules I and A then p II and B then q III and C then r IV and D then s not(I) and not(II) and not(III) and not(IV) and E then t not(I) and not(II) and not(III) and not(IV) and F then u not(I) and not(II) and not(III) and not(IV) and not(A) and not(B) and not(C) and not(D) then v I hope this answers your questions. We will need this functionality pretty soon. Can you give an indication what the priority is for you guys for this functionality? groetjes uit Nederland, Joost 2007/2/7, Edson Tirelli [EMAIL PROTECTED]: Joost, Unfortunatelly, there is no feature implemented for that. But we are discussing, specially the semantics we want to define to such statements ( we call them else and otherwise ). If you have a real use case and you can describe it for us, it may help on deciding which way to go, and at the same time fullfil your needs in the future. Our biggest questions are: * should the else/otherwise part be fired only once if no rule is triggered? or should it fire for each tuple that does not trigger previous rules? What if rules in the otherwise group use different tuples to activate? * should else/otherwise apply to the whole LHS of the rules? Or should there be a way to specify only part of the LHS (like a tag)? Input welcome. Edson Joost de Vries wrote: Hi, We're using excel decision tables to specify our business rules. In one column we enumerate several condition values and describe a specific effect. We'd like to offer business analysts te possibility of describing succinctly what the effect is 'for all other values'. That could be described as an 'else' or 'default' rule. In other words; we don't want to burden business analysts with the necessity to enumerate all other values. What is the right way to do that? Thanks for you help. groetjes, Joost ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users -- 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@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users -- Joost de Vries 06 22375323 werk: [EMAIL PROTECTED] privé: [EMAIL PROTECTED] -- Joost de Vries 06 22375323 werk: [EMAIL PROTECTED] privé: [EMAIL PROTECTED] ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Example of contains operator...
Ok thanks - that worked when partnerList was an ArrayList, how would I code my contains condition if the parternList was a HashMap!? Michael Neale wrote: contains works on the Collection interface. So if parnerList is a ArrayList of String, then you could do: parnerList contains 2900 -- View this message in context: http://www.nabble.com/Example-of-contains-operator...-tf3202978.html#a8944919 Sent from the drools - user mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
RE: [rules-users] fact tuples selection - what are the principles - a bit confused?
No, I'm not concerned with the order in this particular case - just trying to figure out what I should be taking into account or rely on when doing the design. Thanks for taking the time to go through (now that I scrolled through it myself :-) ) this quite lengthy email. Vlad _ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Michael Neale Sent: 12 February 2007 23:53 To: Rules Users List Subject: Re: [rules-users] fact tuples selection - what are the principles - a bit confused? that sounds correct. No you can't really depend on things happening in a certain order. of course it will be consistent between executions for the same data, but you can't count on that. It would mostly be effected by the order in which you assert facts. I guess the question is why are you concerned in what order it does things? Michael On 2/13/07, Olenin, Vladimir (MOH) mailto:[EMAIL PROTECTED] [EMAIL PROTECTED] wrote: Hi, I was trying to find more detailed explanation on how the fact tuples for activations are being selected based on the constraints, but couldn't find much. So, I guess I just want to assert my understanding of this process is correct. Assuming I have the following set of 'Accounts' with the fields: ID | Province | City| Type| Balance 1 | ON | Toronto | Checking| 1000 2 | BC | Vancouver | Checking| 100 3 | ON | Toronto | Visa| 2000 4 | ON | Toronto | Checking|-100 5 | BC | Vancouver | Checking| 100 6 | BC | Vancouver | Visa| 150 7 | AB | Calgary | Checking| 100 7 | AB | Toronto | Checking| 300 I have two rules to process: 1) within each province, the sum of balances on Visa accounts should less then 10 times the sum of balances on Checking accounts (within the same province) 2) within each province, the sum of balances on Checking accounts should be a positive number 3) within each province and within each city, the number of visa accounts should be no more than 2 times the number of checking accounts If I model my business objects like this: 1) Account (id, province, city, type, balance) 2) Province (province) 3) City (province, city) And WorkingMemory will be initialized (for the data above) with: - 7 Account instances (ids 1 through 7) - 3 Province instances (ON, AB, BC) - 3 City instances (Toronto, Vancouver, Calgary) Then the rules containing 'within province' would read like: - Rule '1' When Province($prov: province) $a: Account(province == $prov) Then // accumulate sums on Checking and Visa accounts as Edson showed in previous emails End - The rule containing 'within province, within city' would have then: - Rule '3' When Province($prov: province) City($city: city, province = $prov) $a: Account(province = $prov, city = $city) Then // accumulate sums on Checking and Visa accounts as Edson showed in previous emails - Is this correct business object model to achieve the goal? Do I understand correctly that the LHS statement: Province($prov: province) City($city: city, province = $prov) $a: Account(province = $prov, city = $city) Can be read as: For each province For each city within the province For each account for the given city and province What 'guides' the order in which fact tuples are selected from the set of all facts in the WorkingMemory? Can any particular sequence be guaranteed? Thanks! Vlad ___ rules-users mailing list rules-users@lists.jboss.org mailto:rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users https://lists.jboss.org/mailman/listinfo/rules-users ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Example of contains operator...
On 2/13/07, jdepaul [EMAIL PROTECTED] wrote: Ok thanks - that worked when partnerList was an ArrayList, how would I code my contains condition if the parternList was a HashMap!? You could write an accessor in your model called getPartnerListKeys() which returns getPartnerList().keySet() and then use (partnerListKeys contains 2900) in your rule. I'm not 100% sure (started with JBoss Rules only a couple of days ago), but I'm pretty confident that this should work. hth Marcus Michael Neale wrote: contains works on the Collection interface. So if parnerList is a ArrayList of String, then you could do: parnerList contains 2900 ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Example of contains operator...
That worked just fine - thanks very much for clarification - I'm starting to understand how that works now... example is worth a thousand lines of documentation text... :) Marcus Ilgner wrote: You could write an accessor in your model called getPartnerListKeys() which returns getPartnerList().keySet() and then use (partnerListKeys contains 2900) in your rule. -- View this message in context: http://www.nabble.com/Example-of-contains-operator...-tf3202978.html#a8947081 Sent from the drools - user mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Roll Back Rule / Rule Transactions?
Anytime you modify a object, candidate rules are going to be re-examined. You may need some state variables in addition to this (to control when rules fire, avoid loops, etc), but the basic rules could be: rule AddVcr when $c: Cart(contents contains TV, contents excludes free VCR) then $c.add(free VCR); modify($c); end rule RemoveVcr when $c: Cart(contents excludes TV) then $c.remove(free VCR); modify($c); end You can fill in the rest. Like I said, you probably need some state variables so things don't loop, need to exclude the case where a non-free VCR is legitimately in the cart, etc. But your basic question should be answered with this approach. Don't think procedurally, think in terms of a living system when the changes in objects trigger somewhat asynchronous cascades of matching rules. Calling modify() on a fact is like restarting the whole matching algorithm for any rules that had that fact included in their (possible candidate) constraints. On 2/13/07, Matt Johnston [EMAIL PROTECTED] wrote: I am working on rules for an online shopping cart. Depending on the products in the cart, the customer may get certain discounts. If cart contains a TV, add a free VCR. I can apply these rules, but what about rolling them back? So in the example above, the rule automatically added a free VCR because the cart contained a TV. If the customer removes the TV, I need to roll back the VCR rule and also remove the VCR from the cart. Does anyone know how to do this? Is it possible? Matt Johnston Manager of Internet Content Publishing Group of America p: 615-468-6053 f: 615-468-6153 ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
[rules-users] Short-circuit rules by group?!
I have several rules defined in groups by Customer, so I have number of rules for Walmart, some rules for NIKE, more rules for SomeCustomer... When one of the rules matches for a given customer I need to send an event notification. I need to make sure that I send only ONE event notification per Customer (regardless of how many rules were matched), thus after finding the very first match in the Walmart group, I'd like to activate a rule, and then short-circuit and Skip to the next group of rules for NIKE - to see if any of the matches are found in the next group. I've implemented this functionality using a Match object, which I assert into WorkingMemory whenever I find a match for customer, then all my rules check for absence of Match for given customer... This works, but I wonder if there is a better way to do it - using Agenda Groups, maybe - once I find ONE match for Walmart, skip to the next Agenda Group?! Could someone comment on this? THanks, James -- View this message in context: http://www.nabble.com/Short-circuit-rules-by-group-%21-tf3222142.html#a8949165 Sent from the drools - user mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
RE: [rules-users] Roll Back Rule / Rule Transactions?
NOTE: I'm not a DROOL expert. Keeping this in mind, I'd say You'd need a separate rule which states: - if a cart does NOT contain TV, remove any free VCR from the cart if any Once you retract the 'TV' fact from WorkingMemory and refire the rules (or they will automatically refire?), this new rule will be activate and remove the free VCR from the cart. Just my 2c... Vlad -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Matt Johnston Sent: 13 February 2007 11:21 To: rules-users@lists.jboss.org Subject: [rules-users] Roll Back Rule / Rule Transactions? I am working on rules for an online shopping cart. Depending on the products in the cart, the customer may get certain discounts. If cart contains a TV, add a free VCR. I can apply these rules, but what about rolling them back? So in the example above, the rule automatically added a free VCR because the cart contained a TV. If the customer removes the TV, I need to roll back the VCR rule and also remove the VCR from the cart. Does anyone know how to do this? Is it possible? Matt Johnston Manager of Internet Content Publishing Group of America p: 615-468-6053 f: 615-468-6153 ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Roll Back Rule / Rule Transactions?
You could use truth maintenance, this won't remove something from a list, but it will remove a fact from the working memory when a rule is no longer true. Mark Michael Suzio wrote: Anytime you modify a object, candidate rules are going to be re-examined. You may need some state variables in addition to this (to control when rules fire, avoid loops, etc), but the basic rules could be: rule AddVcr when $c: Cart(contents contains TV, contents excludes free VCR) then $c.add(free VCR); modify($c); end rule RemoveVcr when $c: Cart(contents excludes TV) then $c.remove(free VCR); modify($c); end You can fill in the rest. Like I said, you probably need some state variables so things don't loop, need to exclude the case where a non-free VCR is legitimately in the cart, etc. But your basic question should be answered with this approach. Don't think procedurally, think in terms of a living system when the changes in objects trigger somewhat asynchronous cascades of matching rules. Calling modify() on a fact is like restarting the whole matching algorithm for any rules that had that fact included in their (possible candidate) constraints. On 2/13/07, *Matt Johnston* [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: I am working on rules for an online shopping cart. Depending on the products in the cart, the customer may get certain discounts. If cart contains a TV, add a free VCR. I can apply these rules, but what about rolling them back? So in the example above, the rule automatically added a free VCR because the cart contained a TV. If the customer removes the TV, I need to roll back the VCR rule and also remove the VCR from the cart. Does anyone know how to do this? Is it possible? Matt Johnston Manager of Internet Content Publishing Group of America p: 615-468-6053 f: 615-468-6153 ___ rules-users mailing list rules-users@lists.jboss.org mailto:rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users https://lists.jboss.org/mailman/listinfo/rules-users ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
RE: [rules-users] calls to 'Helper' classes in LHS - are they all owed?
Thanks, Mark. Are there any plans on making return value, predicate and eval expressions indexable (in case it is possible at all)? Would it be included in 3.2 release? I understand that DROOLS can not guarantee that helper method will return the same value each time and probably that's why excludes such cases from index, but the same goes for 'getters' of the fact objects - DROOLS can't guarantee the getter will return the same value each time, so it just have to assume it (and it is outlined in the documentation). There are a few use case that might need this kind of functionality, eg to cache the results of 'associative' lookup. Especially for the 'Decision Tables'. The problem I'm facing right now is I need to 'expand' the list of codes based on some id and use those codes as constraint: MyObject(field = LookupMap.getCodes($param)) Where $param is a value from Decision Table data. In this particular case a set of, say 100 codes, can be described with a simple ID. For more complex cases a pseudo 'set select' expression can be passed as a parameter (eg, LookupMap.getCodes(groupId_1 - grouperId_2), which should return the intersection of codes in groupId_1 and groupId_2). In any case, the key, value pairs returned by LookupMap class would remain the same. Vlad _ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mark Proctor Sent: 12 February 2007 19:16 To: Rules Users List Subject: Re: [rules-users] calls to 'Helper' classes in LHS - are they allowed? We were hoping the community would work with us and improve the documentation over the last year - to date we have had zip :( We will have another documentation drive once we get to the candidate release stage for the current development cycle. We simply don't have the cycles to work on a book, with any luck after we spend 3 to 4 weeks on documentation during hte candidate release stage it should get better, and maybe one day the manual can form the basis of a book. Some ideas for the community to work include the examples in drools-examples, they can even use what I did for drools 2.x as a starting basis, or to provide a really good tutorial on the basics of pattern matching, you can look the public domain clips manual for pointers here. It's not money we need, its time, YOUR time :) If you want to use a helper class it must be in a return value, predicate or eval - none of which are currently indexed. return value and predicate must also be time constant, eval does not have to be. Mark Michael Suzio wrote: I see this in the docs: A d0e1997Predicate constraint can use any valid Java expression as long as it evaluated to a primitive boolean - avoid using any Drools keywords as Declaration identifiers. Previously bound declarations can be used in the expression. Functions used in a Predicate Constraint must return time constant results. and under the discussion of 'eval': Evals cannot be indexed and thus are not as optimal as using Field Constraints. and this in general discussion of constraints and accessors of your objects used in them: Do please make sure that you are accessing methods that take no parameters, and are in-fact accessors (as in, they don't change the state of the object in a way that may effect the rules - remember that the rule engine effectively caches the results of its matching inbetween invocations to make it faster). So, if invoking a helper method is like an eval, I'm thinking Drools computes the match, but then throws it away because it knows this is not a constant expression. Whereas, if it were just a match of an accessor's value vs. a constant String, it could cache that. I'm wildly speculating, only because I want to understand fully what is happening, so I'm throwing stuff out there so the Drools team will have to correct my misapprehensions before I confuse the whole list (*g*). Sometimes reading the Drools documentation is like a Talmudic scholar trying to find the deeper meaning of the sacred words... as much as I want the 3.2 milestone, I want real documentation even more (and *hint hint* -- would probably be willing to pay for it, guys! Can we get an O'Reilly book?) --- Michael On 2/12/07, Steven Williams [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: I believe there is a caveat on functions and helper methods called from the LHS that they need to be constant over time (or at least over the life of the working memory) which then allows matches to be computed as per normal. Steve On 2/13/07, Michael Suzio mailto:[EMAIL PROTECTED] [EMAIL PROTECTED] wrote: The JBoss guys can correct me if I'm wrong, but although I think that works, what you've just done is eliminate any chance to precompute matches and trim down the checks that need to happen to find a rule match. Since the engine can't know that Helper.transform(value) returns a constant value, it has to re-run that every time and it has to reject for matches to the rule
Re: [rules-users] Roll Back Rule / Rule Transactions?
Probably you want to make sure you understand the difference between assert() and assertLogical() and see if that will meet your needs. -- Andrew Thompson - Original Message From: Matt Johnston [EMAIL PROTECTED] To: rules-users@lists.jboss.org Sent: Tuesday, February 13, 2007 11:20:35 AM Subject: [rules-users] Roll Back Rule / Rule Transactions? I am working on rules for an online shopping cart. Depending on the products in the cart, the customer may get certain discounts. If cart contains a TV, add a free VCR. I can apply these rules, but what about rolling them back? So in the example above, the rule automatically added a free VCR because the cart contained a TV. If the customer removes the TV, I need to roll back the VCR rule and also remove the VCR from the cart. Does anyone know how to do this? Is it possible? Matt Johnston Manager of Internet Content Publishing Group of America p: 615-468-6053 f: 615-468-6153 ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users Sucker-punch spam with award-winning protection. Try the free Yahoo! Mail Beta. http://advision.webevents.yahoo.com/mailbeta/features_spam.html ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] calls to 'Helper' classes in LHS - are they all owed?
In theory they can be indexed, but we havne't done it yet, no idea when we'll get time. Patches welcome :) Mark Olenin, Vladimir (MOH) wrote: Thanks, Mark. Are there any plans on making return value, predicate and eval expressions indexable (in case it is possible at all)? Would it be included in 3.2 release? I understand that DROOLS can not guarantee that helper method will return the same value each time and probably that's why excludes such cases from index, but the same goes for 'getters' of the fact objects -- DROOLS can't guarantee the getter will return the same value each time, so it just have to assume it (and it is outlined in the documentation). There are a few use case that might need this kind of functionality, eg to cache the results of 'associative' lookup. Especially for the 'Decision Tables'. The problem I'm facing right now is I need to 'expand' the list of codes based on some id and use those codes as constraint: MyObject(field = LookupMap.getCodes($param)) Where $param is a value from Decision Table data. In this particular case a set of, say 100 codes, can be described with a simple ID. For more complex cases a pseudo 'set select' expression can be passed as a parameter (eg, LookupMap.getCodes(groupId_1 -- grouperId_2), which should return the intersection of codes in groupId_1 and groupId_2). In any case, the key, value pairs returned by LookupMap class would remain the same. Vlad *From:* [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] *On Behalf Of *Mark Proctor *Sent:* 12 February 2007 19:16 *To:* Rules Users List *Subject:* Re: [rules-users] calls to 'Helper' classes in LHS - are they allowed? We were hoping the community would work with us and improve the documentation over the last year - to date we have had zip :( We will have another documentation drive once we get to the candidate release stage for the current development cycle. We simply don't have the cycles to work on a book, with any luck after we spend 3 to 4 weeks on documentation during hte candidate release stage it should get better, and maybe one day the manual can form the basis of a book. Some ideas for the community to work include the examples in drools-examples, they can even use what I did for drools 2.x as a starting basis, or to provide a really good tutorial on the basics of pattern matching, you can look the public domain clips manual for pointers here. It's not money we need, its time, YOUR time :) If you want to use a helper class it must be in a return value, predicate or eval - none of which are currently indexed. return value and predicate must also be time constant, eval does not have to be. Mark Michael Suzio wrote: I see this in the docs: A Predicate constraint can use any valid Java expression as long as it evaluated to a primitive boolean - avoid using any Drools keywords as Declaration identifiers. Previously bound declarations can be used in the expression. Functions used in a Predicate Constraint must return time constant results. and under the discussion of 'eval': Evals cannot be indexed and thus are not as optimal as using Field Constraints. and this in general discussion of constraints and accessors of your objects used in them: Do please make sure that you are accessing methods that take no parameters, and are in-fact accessors (as in, they don't change the state of the object in a way that may effect the rules - remember that the rule engine effectively caches the results of its matching inbetween invocations to make it faster). So, if invoking a helper method is like an eval, I'm thinking Drools computes the match, but then throws it away because it knows this is not a constant expression. Whereas, if it were just a match of an accessor's value vs. a constant String, it could cache that. I'm wildly speculating, only because I want to understand fully what is happening, so I'm throwing stuff out there so the Drools team will have to correct my misapprehensions before I confuse the whole list (*g*). Sometimes reading the Drools documentation is like a Talmudic scholar trying to find the deeper meaning of the sacred words... as much as I want the 3.2 milestone, I want real documentation even more (and *hint hint* -- would probably be willing to pay for it, guys! Can we get an O'Reilly book?) --- Michael On 2/12/07, *Steven Williams* [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: I believe there is a caveat on functions and helper methods called from the LHS that they need to be constant over time (or at least over the life of the working memory) which then allows matches to be computed as per normal. Steve On 2/13/07, *Michael Suzio* [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: The JBoss guys can correct me if I'm wrong, but although I think that works, what you've just
