February 2007 - rules-users - Jboss List Archives

Rule partitioning in a stateful control system

by Steve

Hi, I was wondering what people this might think is good solution to the following scenario... I have a Fact that represents a physical piece of equipment in a control system, this Fact has a number of parameters, param1 and param2. The working memory is used in a stateful manner. Consider two example rules, cs is a global vairable that allows calls back to the control system. rule "Monitor param1" when f : Fact( param1 == 1 ) then cs.DoSomething(f); end rule "Monitor param2" when f : Fact( param2 == 1) then cs.DoSomething(f); end If param1 is updated to == 1, the working memory notified (modifyObject) and the the rules are fired (fireAllRules), consequently the rule "Monitor param1" will be placed onto the Agenda. Assuming that sometime later param2 is updated to == 1, notifing the working memory and firing the rules again will result in rules "Monitor param1" and "Monitor param2" being placed on the agenda. What I really want is just the change to be detected and not for the "Monitor param1" rule to fire again. Is there a pattern to acheive the desired behaviour, I have used agenda-group but am not sure this is the best solution. Thanks for your help.

18 years, 11 months

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Nested exceptions

by Matthew Shaw

Hi Guys, Drools 3 throws "RuntimeDroolsException" However is it nested? I am finding that say one of my objects passed in has a null property (forced error) I get the above exception with a nested null pointer exception. However it does not give any useful information like, what rule/condition the null pointer ocurred in. Am I catching the right exception? Cheers, Matt. Matt Shaw Snr Applications Developer Service Performance & Management Unit Phone: 3247 8666. ext. 94666 This correspondence is for the named persons only. It may contain confidential or privileged information or both. No confidentiality or privilege is waived or lost by any mis transmission. If you receive this correspondence in error please delete it from your system immediately and notify the sender. You must not disclose, copy or relay on any part of this correspondence, if you are not the intended recipient. Any opinions expressed in this message are those of the individual sender except where the sender expressly, and with the authority, states them to be the opinions of the Department of Emergency Services, Queensland.

18 years, 11 months

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fact tuples selection - what are the principles - a bit confused?

by Olenin, Vladimir (MOH)

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

18 years, 11 months

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Help Needed

by shilpa.raghavendra＠wipro.com

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

18 years, 11 months

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calls to 'Helper' classes in LHS - are they allowed?

by Olenin, Vladimir (MOH)

Hi, I was wondering if calls to a Helper class are allowed in LHS of the rule? Eg: Rule myRule When MyObject(objField == Helper.transform("value")) Then // smth End Thanks, Vlad

18 years, 11 months

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Re: [rules-dev] M1 sneak preview

by Mark Proctor

We are still preparing some release notes, and overviews for this release, before we announce it. But for the brave here are some links to binaries: http://labs.jboss.com/file-access/default/members/jbossrules/downloads/3.... http://labs.jboss.com/file-access/default/members/jbossrules/downloads/3.... http://labs.jboss.com/file-access/default/members/jbossrules/downloads/3.... The only drl incompatabilities, that i'm aware of, at this stage is: Primitives are no longer auto-boxed, as we can handle primitives natively now - so code that expected a wrapped primitive will fail to compile. We now implement shadow facts, which means for the moment classes and methods must not be final and implement a default constructor. To indicate this is a "project" preview, it is being released under the drools project name, when it comes time to final, we'll tag and release as jboss rules. Mark Edson Tirelli wrote: > > Mark, > > Follows the list of main features added to core/compiler I was able > to get from JIRA. > Do you want me to ellabora on each item or the JIRA is enough and > we focus on documentation? I think it would be good to start a wiki > page on migration from 3.0.x to 3.2. What do you think? > > []s > Edson > > LANGUAGE IMPROVEMENTS > > * New conditional elements: from, collect, accumulate, forall > http://jira.jboss.com/jira/browse/JBRULES-486 > http://jira.jboss.com/jira/browse/JBRULES-337 > http://jira.jboss.com/jira/browse/JBRULES-341 > http://jira.jboss.com/jira/browse/JBRULES-218 > > * Full support to FOL: nesting of elements now complete > http://jira.jboss.com/jira/browse/JBRULES-218 > > * Support to connective constraints: > http://jira.jboss.com/jira/browse/JBRULES-216 > > * Parser improvements: > - Keyword conflicts resolved > http://jira.jboss.com/jira/browse/JBRULES-214 > - Better support to line breaks > http://jira.jboss.com/jira/browse/JBRULES-269 > - Support to escaped characters inside strings > http://jira.jboss.com/jira/browse/JBRULES-519 > > * Primitive type support: no more autoboxing/unboxing > http://jira.jboss.com/jira/browse/JBRULES-527 > > * Support to Templates: > http://jira.jboss.com/jira/browse/JBRULES-330 > > * Support to additional predicate syntax: > http://jira.jboss.com/jira/browse/JBRULES-556 > > CORE IMPROVEMENTS: > > * Shadow facts: > http://jira.jboss.com/jira/browse/JBRULES-44 > > * Support to constraints between fields of the same object: > http://jira.jboss.com/jira/browse/JBRULES-515 > > * Performance improvements > http://jira.jboss.com/jira/browse/JBRULES-484 > http://jira.jboss.com/jira/browse/JBRULES-498 > http://jira.jboss.com/jira/browse/JBRULES-526 > > * Specialized "exists" node for performance: > http://jira.jboss.com/jira/browse/JBRULES-547 >

18 years, 11 months

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Sample jboss rules application running out of memory

by Jeevan Tambuluri

I am writing a sample application that is trying to create 150,000 facts. After 100,000 facts have been created and asserted, I get the following error: java.lang.OutOfMemoryError: Java heap space The memory consumption of the java process is no more than 85MB just before exception is raised, and my machine has plenty of memory (2GB). Is it possible to tell eclipse IDE to use more heap space (passing -Xmx512m to java ) when it runs the application? Thanks Jeevan

18 years, 11 months

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Memory requirements for "working memory"

by Jeevan Tambuluri

Hello All, We are planning to use a rules engine (specifically JBoss rules) for our application which can potentially have upto 1,000,000 facts to crunch through, which can take up a lot of memory. I am interested in any techniques that could be used to reduce memory footprint while holding large number of facts in working memory. Also, our requirements dictate that we maintain a stateful working memory. One thing hat comes to my mind is to demand-fetch field values for java objects at get*() methods on fact objects are invoked, but if rules are touching most of the fields of the facts, then memory would be filled up sooner or later anyway. I know the question is not directly related to JBoss rules, so I apolagize if this is not the appropriate forum to pose this question... Thanks Jeevan

18 years, 11 months

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"not exists MyObject" - is it a valid LHS condition?

by Olenin, Vladimir (MOH)

Hi, I wonder if the combination of 'not' and 'exists' keywords is a valid one and therefore the construct like rule "myrule" when not exist MyObject(param matches "somepattern") then System.out.println("Object for pattern 'somepattern' doesn't exisit"); End Thanks. Vlad PS: basically I need to trigger a rule if some set of facts is NOT found and I need to trigger it only once.

18 years, 11 months

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What can be done in RHS block...

by jdepaul

I have a simple rule set working: I assert a Fact and Drools matches multiple rules per Fact as desired - now I need to do something meaningful when one OR MORE rules matches - i.e. I need to be able to send a JMS message for every Rule match to the interested Party, or invoke some type of process when Drools finds the right MULTIPLE conditions for me... Examples I've seen only show how to update/modify the Fact, or how to print out a Println - how do I get beyond that? Here's my simple rule with functions - any suggestions will be welcome: rule "Customer Match" salience 100 when custGI : GateIn ( matched==false, customerId == "NISSAN", destinationLocation matches "^SF.*" ) then System.out.println("\nFound Customer Match"); notifyPartner(custGI.getCustomerId()); end rule "Shipper Match" salience 90 when shipperGI : GateIn ( matched==false, primaryShipperId == "YELLOW" ) then System.out.println("\nFound Shipper Match"); notifyPartner(shipperGI.getPrimaryShipperId()); end // Match found - notify customer function void notifyPartner(String _partner ) { System.out.println("Notifying Partner " + _partner ); /* * How do I invoke a notification Service from here?! */ } -- View this message in context: http://www.nabble.com/What-can-be-done-in-RHS-block...-tf3189882.html#a88... Sent from the drools - user mailing list archive at Nabble.com.

18 years, 11 months

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rules-users February 2007