June 2009 - rules-users - Jboss List Archives

by Mark Proctor

For anyone looking for a good and complex example on how to write rules properly, please look at Conways Game of Life in drools-examples, for extra bonus points compare it to the old version in M1. You'll see nearly all the logic is moved from java to the drl and we have removed the need for nested objects by using objects relaitionally, which also allows us to exploit cross products to drive the application. Mark

1 month

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FW: Implementation of expert system

by Binyala, Krishna Gopal IN BLR SISL

Hello, I am new to drools community... I want to develop an expert system for medical application using drools. can you please let me know how to use history data in drools... Because as far as i know we have to keep all the data in the working memory to access. How should i implement such system? Would be better if you can provide some reference to existing expert system implemented using drools. Thanks in advance. Krishna Gopal In three words I can sum up everything I've learned about life: it goes on... Important notice:This e-mail and any attachment thereto contains corporate proprietary information. If you have received it by mistake, please notify us immediately by reply e-mail and delete this e-mail and its attachments from your system. Thank You.

12 years, 9 months

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enquiry on drools webservice

by Prem Kumar L

13 years

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java.lang.OutOfMemoryError: Java heap space

by vdelbart

Hello, In my tests of the 4.0.3, I have some : java.lang.OutOfMemoryError. So, I try a simple test with 10.000 sequential execution of 1 rule with no context and just a workingmemorylogger and I have the error : java.lang.OutOfMemoryError: Java heap space My code is : public class ExecReglesMemotyTest { private static final Reader DRL = new InputStreamReader(ExecReglesMemotyTest.class .getResourceAsStream("/rules/exemple.drl")); private static final String FICHIER_LOG = "session"; /** * @param args */ public static void main(String[] args) { try { PackageBuilder builder = new PackageBuilder(); builder.addPackageFromDrl(DRL); RuleBase ruleBase = RuleBaseFactory.newRuleBase(); ruleBase.addPackage(builder.getPackage()); for (int i = 0; i < 10000; i++) { StatefulSession session = ruleBase.newStatefulSession(); WorkingMemoryFileLogger logger = new WorkingMemoryFileLogger(session); logger.setFileName(FICHIER_LOG); session.fireAllRules(); logger.writeToDisk(); session.dispose(); } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } } with this rule (doesn't matter): #created on: Fri Nov 09 15:48:45 CET 2007 package initPackage #list any import classes here. rule "ERG9" when then end I try this in 4.0.1, and it's working (no OutOfMemoryError) What's the problem ? thanks for any information, V. -- View this message in context: http://www.nabble.com/java.lang.OutOfMemoryError%3A-Java-heap-space-tf477... Sent from the drools - user mailing list archive at Nabble.com.

13 years

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OSGi version of Drools

by Flavius Vespasianus

Hello, is there anywhere a OSGi bundle with Drools 4.0.7? I know about com.springsource.org.drools.* but these had a lot of additional dependencies and I wasn't able to get them work. My problem is that I need to have three projects: one is the basic library which uses Drools very intensively. The second project is editor - an Eclipse plugin (that's why I need the OSGi bundle) using some classes from the basic library. It doesn't use Drools, but there is a dependency. The third project is classic Java application, also using the basic library. The basic library was originally created using standard Drools project wizard (I have downloaded the Eclipse Drools plugin - org.drools.eclipse). But when I tried to deploy it as an Eclipse plugin, it couldn't find the Drools classes. I found a little workaround - I have compiled the binaries (drools-core, drools-compiler and from libs the mvel, antlr3 and eclipse-jdt-core) into separate plugin using "Create a plugin from existing jars" wizard. But if I add this dependency to the basic library, I get a NullPointerException error on every dslr file and I cannot run the application properly). At least the second project (editor) can be compiled. What am I doing wrong? Or can I find somewhere the binaries compiled correctly into OSGi bundle? Thanks a lot! Flavius

13 years, 10 months

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MVEL expression

by Femke De Backere

Hi, The following expression keeps returning the error [112,32]: [ERR 103] Line 112:32 no viable alternative at input '+' in rule "RuleFlow-Split- masterproef.ruleflows.shortsedation-18-22" in pattern Patient: Patient(sedation.ultiva+0.02 > 0.1) with sedation.ultiva returning a double What am I doing wrong? Thx, Femke

13 years, 11 months

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Log4j in the rules?

by granz＠MIT.EDU

Hi, Is it possible to use Log4j inside the rules (RHS)?? (drl file) Thanks, Fabrice

14 years, 1 month

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How to Access and Execute Rules from Database

by Ashish Soni

Hi All , I am able to configure oracle database in drools but now i am not able to find how can i load rules from the DB and execute them , I gone through the documentation but not able to get much information or might be i am missing something. If any one can provide me a example or some pointer ,hints then it would be helpful. Regards, Ashish

14 years, 4 months

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how to import rules from a drl to another drl file

by raj_drools

hi , i'm using drools 4.7 . i have requirement in Drools . i have some common rules which can be used in many places . so i want to keep them in seperate drl file and impot those rules in another drl file in same package or in other . how can i share rules or functions to other rules which are in other drl files . thanks for the help in advance . regards , sekhar -- View this message in context: http://www.nabble.com/how-to-import-rules-from-a-drl-to-another-drl-file-... Sent from the drools - user mailing list archive at Nabble.com.

14 years, 9 months

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About for and inheritance

by Chris Woodrow

Hi, I recently find out a few issues using for, and I wanted to share it with you. I made a simple exemple to illustrate my purpose. My classes are (I did not represent accessors & constructors): public class Cheese { protected String name; } public class FrenchCheese extends Cheese{ private String smell; } public class Person { private Cheese likes; } Here is my rule set : package rules rule "likes cheese" when $person : Person () Cheese( ) from $person.getLikes() then System.out.println("likes cheese"); end rule "likes french cheese" when $person : Person () FrenchCheese( ) from $person.getLikes() then System.out.println("likes french cheese"); end First test : Cheese cheese = new FrenchCheese("good", "camembert"); Person person = new Person(); person.setLikes(cheese); Output : likes french cheese likes cheese Wich is expected... Second test : Cheese cheese = new Cheese(); Person person = new Person(); person.setLikes(cheese); Output : likes french cheese likes cheese That's the first strange thing. As far as I am concerned, rule "likes french cheese" should not match (since a Cheese is not a FrenchCheese). I made a change to the second rule : rule "likes french cheese" when $person : Person () FrenchCheese( smell == "good" ) from $person.getLikes() then System.out.println("likes french cheese"); end Third test : Cheese cheese = new Cheese(); Person person = new Person(); person.setLikes(cheese); output : It throwed an exception : Exception in thread "main" java.lang.ClassCastException: rules.Cheese I am not saying the ClassCastException is not to expect in such a case but I think I would simply expect it not to match (as far as a Cheese is not a FrenchCheese). Chris

14 years, 9 months

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rules-users June 2009