February 2011 - rules-users - Jboss List Archives

Questions concerning Java and rules / Flexibility

by Martin Richardsen

I am a complete novice concerning Drools and have some basic questions, which arised after studying the drools documentation and some examples as well. As far as I got it right, you have two possibilities to work with drools 1) You write a java program, rules / actions are hard coded inline or saved in text files / excel sheets / XML files etc. After importing the necessary drools classes you call the drools interface routines, with the following functionalities: load rules, providing working memory, adding facts und finally starting the rule engine (e.g. firing rules). 2) You use the capabilities of the Drools GUI tools (such as Guvnor), which allows entering rules, objects and actions via GUI tools. Here, I don't get the point whether a part of the java code is generated automatically, or whether you have to write your java classes by yourself, as presented in possibility 1 (above), but without coding the rules by yourself in the source code / external input files. I would be very pleased, if anyone could explain me the essential difference between the two approaches and accordingly tell me what the advantage of using method 2) would be in contrast to method 1), particularly concerning the necessary java coding. --- Well and there would be another question, if you write down your rules and the corresponding software, which accesses the rules, is it possible to add some rules later, without rewriting/recompiling your software? Thanks in advance! Cheers, Martin.

14 years, 10 months

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guvnor integration gives 401 error

by tsarkar

Hi, I have my application running in one instance of jboss server and guvnor running in another. When my application code tries to fireAllRules created in guvnor, the following error comes: 16:00:12,131 INFO [STDOUT] java.lang.RuntimeException: KnowledgeAgent exception while trying to deserialize KnowledgeDefinitionsPackage Caused by: java.io.IOException: Server returned HTTP response code: 401 for URL: http://pcbng100:18080/drools-guvnor/org.drools.guvnor.Guvnor/package/com.... When I use same code within a java file with main method & run as java application in eclipse, the rules fire properly.Any suggestions would be appreciated.

14 years, 10 months

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Drools Java and .Net

by Gorantla, Bhaskar (GE Capital)

We are looking for a rules engine that has the following characteristics. 1. Supports both Java and .net 2. Provides a business user friendly UI for creating/editing rules 3. Supports versioning 4. The rues in the rules repository are accessible to both Java and .net applications - Nice to have Do you know whether Drools supports all the above? Thanks

14 years, 10 months

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Who writes your rules? Dev vs. BA

by cclark01

My company is looking to use Guvnor in a new application we're writing. Part of the appeal is the idea that Business Analysts will be able to go and write rules by themselves. However, in doing a small proof-of-concept, it appears that you need intimate knowledge of the object model in order to write any meaningful rules. I've read up on DSL and it looks like that might help things, but it also sounds like DSL is the kind of thing that gets built up over time. So... what's your experience? Do BA's or Developers write the rules in your applications? Does the complexity of the object model play a role in who can write rules, or is it just a matter of training? If you've created a DSL, how easy/quick was it? If not, any particular reason why not? I'm looking for some "real life" experiences so that we can have appropriate expectations going into the project. Thanks, Chris -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Who-writes-your-rules... Sent from the Drools - User mailing list archive at Nabble.com.

14 years, 10 months

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Timer Event Node and Persistence

by jschmied

Hi! Playing around I created a ruleflow with a timer event. When the timer is firing and I try to persist the ruleflow the timer keeps fireing and I get the following exception: org.drools.RuntimeDroolsException: Unexpected exception executing action org.jbpm.process.instance.event.DefaultSignalManager$SignalProcessInstanceAction@82b92b at org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:1000) at org.drools.impl.StatefulKnowledgeSessionImpl.executeQueuedActions(StatefulKnowledgeSessionImpl.java:832) at org.jbpm.process.instance.event.DefaultSignalManager.signalEvent(DefaultSignalManager.java:89) at org.jbpm.process.instance.timer.TimerManager$ProcessJob.execute(TimerManager.java:164) at org.drools.time.impl.JDKTimerService$JDKCallableJob.call(JDKTimerService.java:147) at org.drools.persistence.jpa.JpaJDKTimerService$JpaJDKCallableJob.internalCall(JpaJDKTimerService.java:81) at org.drools.persistence.jpa.JpaJDKTimerService$JpaJDKCallableJob.access$100(JpaJDKTimerService.java:64) at org.drools.persistence.jpa.JpaJDKTimerService$JDKCallableJobCommand.execute(JpaJDKTimerService.java:97) at org.drools.persistence.jpa.JpaJDKTimerService$JDKCallableJobCommand.execute(JpaJDKTimerService.java:85) at org.drools.persistence.SingleSessionCommandService.execute(SingleSessionCommandService.java:295) at org.drools.persistence.jpa.JpaJDKTimerService$JpaJDKCallableJob.call(JpaJDKTimerService.java:76) at org.drools.persistence.jpa.JpaJDKTimerService$JpaJDKCallableJob.call(JpaJDKTimerService.java:64) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) at java.util.concurrent.FutureTask.run(FutureTask.java:138) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:98) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:207) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:619) Caused by: org.drools.WorkItemHandlerNotFoundException: Could not find work item handler for Log at org.drools.persistence.jpa.processinstance.JPAWorkItemManager.throwWorkItemNotFoundException(JPAWorkItemManager.java:60) at org.drools.persistence.jpa.processinstance.JPAWorkItemManager.internalExecuteWorkItem(JPAWorkItemManager.java:55) at org.jbpm.workflow.instance.node.WorkItemNodeInstance.internalTrigger(WorkItemNodeInstance.java:101) at org.jbpm.workflow.instance.impl.NodeInstanceImpl.trigger(NodeInstanceImpl.java:122) at org.jbpm.workflow.instance.impl.NodeInstanceImpl.triggerConnection(NodeInstanceImpl.java:185) at org.jbpm.workflow.instance.impl.NodeInstanceImpl.triggerCompleted(NodeInstanceImpl.java:150) at org.jbpm.workflow.instance.node.ActionNodeInstance.triggerCompleted(ActionNodeInstance.java:55) at org.jbpm.workflow.instance.node.ActionNodeInstance.internalTrigger(ActionNodeInstance.java:51) at org.jbpm.workflow.instance.impl.NodeInstanceImpl.trigger(NodeInstanceImpl.java:122) at org.jbpm.workflow.instance.impl.NodeInstanceImpl.triggerConnection(NodeInstanceImpl.java:185) at org.jbpm.workflow.instance.impl.NodeInstanceImpl.triggerCompleted(NodeInstanceImpl.java:150) at org.jbpm.workflow.instance.node.JoinInstance.triggerCompleted(JoinInstance.java:152) at org.jbpm.workflow.instance.node.JoinInstance.internalTrigger(JoinInstance.java:65) at org.jbpm.workflow.instance.impl.NodeInstanceImpl.trigger(NodeInstanceImpl.java:122) at org.jbpm.workflow.instance.impl.NodeInstanceImpl.triggerConnection(NodeInstanceImpl.java:185) at org.jbpm.workflow.instance.impl.NodeInstanceImpl.triggerCompleted(NodeInstanceImpl.java:150) at org.jbpm.workflow.instance.node.ActionNodeInstance.triggerCompleted(ActionNodeInstance.java:55) at org.jbpm.workflow.instance.node.ActionNodeInstance.internalTrigger(ActionNodeInstance.java:51) at org.jbpm.workflow.instance.impl.NodeInstanceImpl.trigger(NodeInstanceImpl.java:122) at org.jbpm.workflow.instance.impl.NodeInstanceImpl.triggerConnection(NodeInstanceImpl.java:185) at org.jbpm.workflow.instance.impl.NodeInstanceImpl.triggerCompleted(NodeInstanceImpl.java:150) at org.jbpm.workflow.instance.impl.ExtendedNodeInstanceImpl.triggerCompleted(ExtendedNodeInstanceImpl.java:47) at org.jbpm.workflow.instance.node.StateBasedNodeInstance.triggerCompleted(StateBasedNodeInstance.java:162) at org.jbpm.workflow.instance.node.TimerNodeInstance.triggerCompleted(TimerNodeInstance.java:135) at org.jbpm.workflow.instance.node.TimerNodeInstance.signalEvent(TimerNodeInstance.java:125) at org.jbpm.workflow.instance.impl.WorkflowProcessInstanceImpl.signalEvent(WorkflowProcessInstanceImpl.java:333) at org.jbpm.process.instance.event.DefaultSignalManager$SignalProcessInstanceAction.execute(DefaultSignalManager.java:117) at org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:998) ... 18 more I think the timer calls object in the disposed session? How do I stop the timer event before disposing the session? Should the timer run again after reloading the ruleflow? (Couldn't get so far) Thanks juergen -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Timer-Event-Node-and-... Sent from the Drools - User mailing list archive at Nabble.com.

14 years, 10 months

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How do I prevent the package registry from being null in my package builder?

by retoy

I just installed Drools and wanted to build a simple RuleFlow. But When I add any process containing constraints or rules to my Knowledgebuilder, I'm always getting a NullPointerException, because the "package registry" seems to be null. ..... java.lang.NullPointerException at org.drools.compiler.ProcessBuilder.buildProcess(ProcessBuilder.java:119) at org.drools.compiler.ProcessBuilder.addProcessFromFile(ProcessBuilder.java:223) at org.drools.compiler.PackageBuilder.addProcessFromXml(PackageBuilder.java:447) at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:503) at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:25) ..... ProcessBuilder.java:118 PackageRegistry pkgRegistry = this.packageBuilder.getPackageRegistry(process.getPackageName()); ProcessBuilder.java:119 org.drools.rule.Package p = pkgRegistry.getPackage(); ..... The ruleflow is successfully validated though when i press that button in eclipse... Can somebody give me a hint what's missing? Thanks! -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/How-do-I-prevent-the-... Sent from the Drools - User mailing list archive at Nabble.com.

14 years, 10 months

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Drools Guvnor and BPMN processes...

by bob.breitling

I have a package in the Guvnor that has several rules and one BPMN process. When I get the package in my app by accessing the Guvnor, I download the ChangeSet.xml and I get all my rules but I never get the process. Here is a snipet of my code: UrlResource resource = (UrlResource) ResourceFactory.newUrlResource(myChangeSetURL); KnowledgeAgent kagent = KnowledgeAgentFactory.newKnowledgeAgent("myAgent"); kagent.applyChangeSet(resource); guvnorKnowledgeBase = kagent.getKnowledgeBase(); Is there something I'm missing to get my processes too? TIA, Bob -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Drools-Guvnor-and-BPM... Sent from the Drools - User mailing list archive at Nabble.com.

14 years, 10 months

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InsertLogical on web based decision tables

by Karolis Petrauskas

Hi all, I am using Drools Guvnor to manage rules. Some of them are in the form of decision tables. My rules highly rely on the knowledge management (inserLogical) functionality. Is it possible to make web based decision tables to generate insertLogical statements instead of insert statements? In the GUI I can't find any option related to this. Is there any way to do it or maybe some work around for this? Redesign of rules to make them not dependent on insertLogical functionality would make those rules much more complicated. If there are no ways to do this (or workarounds for this), could you point me to key places in the source code related to web based decision table handling? I would try to implement this functionality by myself. Or maybe this functionality was omitted intentionally? If yes, what are the reasons for that? Thanks in advance, Karolis Petrauskas

14 years, 10 months

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How to add jars of DROOLS/Drools to project manifest

by drools10

Hi, I am running guvnor in 1 instance of my jboss server & my application in another instance of same server. My application code refers to guvnor using ChangeSet.xml. When In run my code, it gives the following error: 16:00:12,131 INFO [STDOUT] java.lang.RuntimeException: KnowledgeAgent exception while trying to deserialize KnowledgeDefinitionsPackage 16:00:12,131 INFO [STDOUT] at org.drools.agent.impl.KnowledgeAgentImpl.rebuildResources(KnowledgeAgentImpl.java:418) 16:00:12,131 INFO [STDOUT] at org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet(KnowledgeAgentImpl.java:120) 16:00:12,131 INFO [STDOUT] at org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet(KnowledgeAgentImpl.java:109) But when I access the guvnor through similar code in a java class with main method(using run as>java application) it works fine, as long as my .classpath file has the following entry: <classpathentry kind="con" path="DROOLS/Drools"/> Any idea how I can add the jar files referred by this to my projects manifest.mf, which I think would solve the issue when application refers to the guvnor. -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/How-to-add-jars-of-DR... Sent from the Drools - User mailing list archive at Nabble.com.

14 years, 10 months

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statefulSession

by saurabh maheshwari

Hi, I am very new in drools . can any tell me what is the difference b/w org.drools.runtime.StatefulKnowledgeSession and org.drools.StatefulSession*? * Please inform if you have any idea about this. Regards Saurabh

14 years, 10 months

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rules-users February 2011