October 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

3 months

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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, 11 months

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enquiry on drools webservice

by Prem Kumar L

13 years, 2 months

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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, 2 months

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Re: [rules-users] Error running Drools 5.0 HelloWorldExample on WebSphere 6.1

by Blythe, Marshall

A quick follow-up: this error occurs only when I have rules using the MVEL dialect. I rewrote the MVEL rule in the HelloWorld.drl to use the Java dialect, and now the problem is gone. I may need to raise this issue on the MVEL mailing list instead. ----------------------------------------- This e-mail and any attachments may contain CONFIDENTIAL information, including PROTECTED HEALTH INFORMATION. If you are not the intended recipient, any use or disclosure of this information is STRICTLY PROHIBITED; you are requested to delete this e-mail and any attachments, notify the sender immediately, and notify the LabCorp Privacy Officer at privacyofficer(a)labcorp.com or call (877) 23-HIPAA.

13 years, 11 months

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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

14 years

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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

14 years, 1 month

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Drools 5 PseudoClock with StatelessKnowledgeSession

by Ben Scott

_______________________________________________________________________________________ Note: This e-mail is subject to the disclaimer contained at the bottom of this message. _______________________________________________________________________________________ I'm wanting to use the date-effective and date-expiry rule metadata to add date specific rule variants within my app. To test these I was planning on using the pseudo clock and setting the expected date prior to executing the rules within a StatelessKnowledgeSession. I can set the clock easily enough, but can't understand why the getSessionClock() method is missing? It's on the StatefulKnowledgeSession, but not on the Stateless. I'm initialising the session like this: SessionConfiguration sessionConfiguration = new SessionConfiguration(); sessionConfiguration.setClockType( ClockType.PSEUDO_CLOCK ); StatelessKnowledgeSession session = _testKnowledgeBase.newStatelessKnowledgeSession(sessionConfiguration); The only thing I could think of to set the pseudo clock was to write a command something like: private static class SetPseudoClockCommand implements org.drools.process.command.Command<Boolean> { public Boolean execute(ReteooWorkingMemory session) { // Set the clock to the current date pseudoSessionClock.advanceTime(new DateTime().getMillis(), TimeUnit.MILLISECONDS); // Add a couple of days pseudoSessionClock.advanceTime(2, TimeUnit.DAYS); return true; } } But this doesn't appear to take any effect whilst rules are running. Is there another way to get programmatic access to the session clock, or some better way of changing the underlying date prior to rule execution? Ben. _______________________________________________________________________________________ The information transmitted in this message and its attachments (if any) is intended only for the person or entity to which it is addressed. The message may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon this information, by persons or entities other than the intended recipient is prohibited. If you have received this in error, please contact the sender and delete this e-mail and associated material from any computer. The intended recipient of this e-mail may only use, reproduce, disclose or distribute the information contained in this e-mail and any attached files, with the permission of the sender. This message has been scanned for viruses with Symantec Scan Engine and cleared by MailMarshal. _______________________________________________________________________________________

14 years, 3 months

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Persistence of events

by Maciej Prochniak

Hello, Is it possible to persist events (from drools fusion) with default jpa mechanism? When I try to do this 'just like that' I get exception like org.drools.common.DefaultFactHandle incompatible with org.drools.common.EventFactHandle It seems that session marshaller is not really aware of certain objects being events, not facts. The code I try is more or less like: UserTransaction ut = ... StatefulKnowledgeSession session = JPAKnowledgeService .newStatefulKnowledgeSession(kbase, null, env); ut.begin() session.insert(e1); ut.commit(); StatefulKnowledgeSession sessionPersisted = JPAKnowledgeService.loadStatefulKnowledgeSession( session.getId(), kbase, null, env ); ut.begin() sessionPersisted.insert(e2); (*) <- fails ut.commit(); When I use session instead of sessionPersisted - it works fine, when e2 is a fact, not an event - it also works I know that it may be awkward to persist events which have time limitations, but I want to use time limits in rules which are like few days - so I want to have some persistence in case of server shutdown. I would be grateful for any comment, br, maciek prochniak

14 years, 3 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, 3 months

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rules-users October 2009