September 2010 - 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

2 months

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Starting resource change scanner and notifier in drools-server.

by Graham Thomson

Hi, I would like to ask for help with setting up drools-server with Guvnor. I am using version 5.1.1 of both. I am trying to set up an instance of drools-server in Tomcat that periodically loads new updates of packages published in Guvnor (both drools-server and Guvnor run in the same instance of Tomcat). My change set definition is as follows: <?xml version="1.0" encoding="UTF-8"?> <change-set xmlns='http://drools.org/drools-5.0/change-set' xmlns:xs='http://www.w3.org/2001/XMLSchema-instance' xs:schemaLocation='http://drools.org/drools-5.0/change-set http://anonsvn.jboss.org/repos/labs/labs/jbossrules/trunk/drools-api/src/...'> <add> <resource source='http://localhost:8080/drools-guvnor/org.drools.guvnor.Guvnor/package/<one of my packages>/LATEST' type='PKG' basicAuthentication="enabled" username="<username>" password="" /> <resource source="http://localhost:8080/drools-guvnor/org.drools.guvnor.Guvnor/package/<another of my packages>/LATEST" type="PKG" basicAuthentication="enabled" username="<username>" password="" /> </add> </change-set> My knowledge-services.xml configuration is as follows (based on the unit test examples highlighted in http://article.gmane.org/gmane.comp.java.drools.user/20992/match=drools+s...): <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:drools="http://drools.org/schema/drools-spring" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd http://drools.org/schema/drools-spring http://anonsvn.jboss.org/repos/labs/labs/jbossrules/trunk/drools-containe..."> <drools:resource-change-scanner id="s1" interval="5" /> <drools:execution-node id="node1" /> <drools:ksession id="ksession1" type="stateless" kbase="kbase1" node="node1"/> <drools:kbase id="kbase1" node="node1" /> <drools:kagent id="kagent1" kbase="kbase1"> <drools:resources> <drools:resource type="CHANGE_SET" source="classpath:changeset.xml" /> </drools:resources> </drools:kagent> </beans> On loading drools-server, the resources listed in the change set are loaded and available. The problem is that when a new package built and published in Guvnor, drools-server does not detect this and update itself. The effect is the same as if a KnowledgeAgent were used locally and ResourceFactory.getResourceChangeNotifierService().start(); ResourceFactory.getResourceChangeScannerService().start(); were not called. This leads me to the assumption that drools-server does not start these services by default. My question is then can/how do I configure drools-server to start these services such that it will update new changes from Guvnor automatically? Thanks a lot for any help you can offer, Cheers, Graham.

11 years, 7 months

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how to debug rules in JBoss AS?

by Marina

Hello, I know one can debug rules (put breakpoints in .drl and ruleflow files) when running/debugging an application as a Drools Application. However, I would like to debug rules when my application is running in JBoss AS - just like we do a normal debugging of a Remote application running in a different JVM ,by enabling the JDWP on the server (-Xrunjdwp:transport=dt_socket,address=8787,server=y,suspend=n) and then connecting to the specified port. Basically, I would like to be able to debug both my Java classes and rules together. Is it possible? thanks, Marina

12 years, 4 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, 10 months

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enquiry on drools webservice

by Prem Kumar L

13 years, 1 month

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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, 1 month

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Problem with gateway(diverge) executing first

by Jian Feng Ng

13 years, 3 months

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Challenge! Using javassist and drools presents an issue with drl

by markricard

In order to make writing drl files easy and not requiring writers to be developers, I have written some JavaAssist code that dynamically creates a subclass and new methods in memory. If for example there is a REAL java class called 'com.foo.Instance'. Via javasssist, I create a new in-memory subclass called 'com.foo.InstanceEx'. The new class dynamically creates a new getter called getFoo(). The drl writer would like to directly reference 'foo' in the drl file like so: when i : Instance(foo == 'fee') The problem is, in order to reference foo, I would need the drl file to do this: import com.rrd.xspace.drools.InstanceEx; But I cannot do that because InstanceEx does not exist at runtime. The error I get, which is an obvious one, is "Unable to create Field Extractor for 'foo' of '[ClassObjectType class=com.foo.Instance]' in rule 'Test' : [Rule name='Test']" Is there a way to include a dynamic import of a JavaAssist class while I am constructing the KnowledgeBase instances to run the rules so that I can reference that new method? I would hope to have something similar to: KnowledgeBuilder kbuilder = .... kbuilder.addImport("com.foo.InstanceEx") or kbuilder.addClass(Class.forName("com.foo.InstanceEx")) Any help GREATLY appreciated. -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Challenge-Using-javas... Sent from the Drools - User mailing list archive at Nabble.com.

13 years, 6 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, 10 months

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Difference between Rule Base and Knowledge Base

by Swapnil Sawant

Hi, I had a very basic doubt. 'Rule Base' and 'Knowledge Base' are two different concepts (may be from implementation point of view )? I got this doubt when I was going through section '1.4.7.2.Â Drools execution server' of drools guvnor (v5.0) where it was written like : The drools execution server (drools-server) module is a war which you can deploy to execute "knowledgebases (rulebases)" remotely for any sort of client application The thing is that , I have created Knowledge base from changeset.xml as follows : kagent = KnowledgeAgentFactory.newKnowledgeAgent( "MyRuleAgent" ); kagent.applyChangeSet( ResourceFactory.newUrlResource( changesetUrl ) ); kbase = kagent.getKnowledgeBase(); Now if I wish to get Rule Base corresponding to my changeset(or rather my DRL file) using 'this kbase object' , how can I do that ? Thanks, Swapnil Sawant This Email may contain confidential or privileged information for the intended recipient (s) If you are not the intended recipient, please do not use or disseminate the information, notify the sender and delete it from your system. ______________________________________________________________________

13 years, 10 months

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rules-users September 2010