October 2013 - rules-users - Jboss List Archives

What is the side-effect of using the CE "from"?

by Sonata

Hi, I remember seeing some best practice and since then it has been in my mind that the Drools team actually against the use of CE "from". I do however find it really useful and use it alot (and in fact everywhere). Could the Drools team clear this up? For example, I found it useful because 1. When a fact is inserted into the working memory, "from" conditions are not evaluated. This is good because the fact may not be ready yet (e.g. need updating to fill in more stuff to complete it in some rules) and evaluating the fact too early may cause exceptions. Using "from" does not suffer from this issue. 2. Also, this is good because I dont get unnecessary calls to getters of that newly inserted fact for all the rules in the kbase with the class of that fact in the LHS because they may not be triggered at the end (e.g. filtered by agenda-groups, activation-groups). I put auditing codes on my getters to track usage and profiling, hence each call to getters is quite expensive for me (elapse time recording, database updating, etc.) 3. Once a preceding "from" condition fails, all the subsequent "from" conditions will not be evaluated. Again, this is good to save unnecessary member accesses to boost performance. I know what I dont get using "from" is same pattern node sharing (i.e. same condition pattern across rules is evaluated only once when "from" is not used), but it seems to me that the pros outweigh the cons. Thanks the Drools team for clarifying -- View this message in context: http://drools.46999.n3.nabble.com/What-is-the-side-effect-of-using-the-CE... Sent from the Drools: User forum mailing list archive at Nabble.com.

12 years, 11 months

2
2
0 / 0

session deserialization slidingTimeWindow NPE

by Alexander Wolf

Sometimes (I am not sure what the actual reason is yet ) I get following NPE when I try to deserialize my ksessions: java.lang.NullPointerException at org.drools.common.ConcurrentNodeMemories.getNodeMemory(ConcurrentNodeMemories.java:63) at org.drools.common.AbstractWorkingMemory.getNodeMemory(AbstractWorkingMemory.java:1034) at org.drools.rule.SlidingTimeWindow$BehaviorExpireWMAction.<init>(SlidingTimeWindow.java:460) This is not a new problem, I found an old post on the mailing list, that describes the same here: (but unfortunately without any answers) http://drools.46999.n3.nabble.com/rules-users-5-5-0-Final-persistence-to-... Apparently it's got something to do with slidingTime in one rule, but as it does not always occur - am I quite puzzled. Any Ideas or Workarounds? - Alex

12 years, 11 months

2
5
0 / 0

Decision Table Row #

by nzhu972

Hi, in Drools 5, is there a way to retrieve the row # in the web based decision table? The # column is auto generated and I like to retrieve the row # along with the rest of the table data when a match is found in the table. Thanks -- View this message in context: http://drools.46999.n3.nabble.com/Decision-Table-Row-tp4026392.html Sent from the Drools: User forum mailing list archive at Nabble.com.

12 years, 11 months

3
3
0 / 0

why define the returnedProcessor twice

by scarlettxu

Hi Expert, I am a new guy to drools rules and studying the drools camel server now. And I see in the DroolsPolicy class located in project drools-camel-5.2.0.Final , it define the returnedProcessor twice public Processor wrap(RouteContext routeContext, Processor processor) { RouteDefinition routeDef = routeContext.getRoute(); ToDefinition toDrools = getDroolsNode(routeDef); * Processor returnedProcessor; Processor returnedProcessor;* if (toDrools != null) { returnedProcessor = new DroolsProcess(toDrools.getUri(), processor); } else { returnedProcessor = processor; } return returnedProcessor; } I wonder is it for special purpose ? As I checked from version 5.2.0 Final to 6.0.0RC3 -- View this message in context: http://drools.46999.n3.nabble.com/why-define-the-returnedProcessor-twice-... Sent from the Drools: User forum mailing list archive at Nabble.com.

12 years, 11 months

2
2
0 / 0

Ascending sort by salience results in NPE

by Wolfgang Laun

rule "process Token" salience - $prio // by ascending x25No values when $token: Token( $x25No: x25No ) // match on int x25No $elem: ElemType( $prio: x25No == $x25No ) then retract($token); end All versions 5.[2345].0 crash. Using "0 - $prio" is a workaround. Exception in thread "main" java.lang.NullPointerException at org.drools.base.mvel.MVELSalienceExpression.getValue(MVELSalienceExpression.java:93) at org.drools.common.DefaultAgenda.createActivation(DefaultAgenda.java:579) at org.drools.reteoo.RuleTerminalNode.assertLeftTuple(RuleTerminalNode.java:253) at org.drools.reteoo.SingleLeftTupleSinkAdapter.doPropagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:196) at org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:71) at org.drools.reteoo.JoinNode.propagateFromLeft(JoinNode.java:107) at org.drools.reteoo.JoinNode.assertLeftTuple(JoinNode.java:95) at org.drools.reteoo.SingleLeftTupleSinkAdapter.doPropagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:196) at org.drools.reteoo.SingleLeftTupleSinkAdapter.createAndPropagateAssertLeftTuple(SingleLeftTupleSinkAdapter.java:145) at org.drools.reteoo.LeftInputAdapterNode.assertObject(LeftInputAdapterNode.java:154) at org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObjectSinkAdapter.java:59) at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:235) at org.drools.reteoo.EntryPointNode.assertObject(EntryPointNode.java:240) at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:350) at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:311) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:903) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:847) at org.drools.impl.StatefulKnowledgeSessionImpl.insert(StatefulKnowledgeSessionImpl.java:269) at geninq.Main.execute(Main.java:97) at geninq.Main.main(Main.java:133)

12 years, 11 months

2
1
0 / 0

Why disable properyreactive if amount of properties larger than or equals to 64

by richie

In this code drools-compiler / src / main / java / org / drools / compiler / compiler / PackageBuilder.java (Line 2515): private void setPropertyReactive(Resource resource, TypeDeclaration type, boolean propertyReactive) { *if ( propertyReactive && type.getSettableProperties().size() >= 64 ) {* this.results.add( new DisabledPropertyReactiveWarning( resource, type.getTypeName() ) ); *type.setPropertyReactive( false );* } else { type.setPropertyReactive( propertyReactive ); } } As we can see, if amount of properties is larger than or equals to 64, will disable the property active, why? Is there any special reason? -- View this message in context: http://drools.46999.n3.nabble.com/Why-disable-properyreactive-if-amount-o... Sent from the Drools: User forum mailing list archive at Nabble.com.

12 years, 11 months

4
8
0 / 0

Drools Fusion, best practise?!

by Alexander Wolf

Hey, I try to use drools fusion to detect patterns in an event stream. Each time an event occurs I insert it into my ksession and call fireAllRules(). Most of my rules need to reason over the newest event (the one that just came in) in conjunction with events that happend before or after that. I also have a "state" within my environment. e.g. temperature (HIGH, MEDIUM, LOW). (but also other state variables) e.g. [pseudo code] WHEN temperature MEDIUM or LOW newest event (value >= 20) last previous event (value >= 20) then set temperature to HIGH Now I run into lots of problems with this e.g. that I can not easily get the "newest" and "last previous" events. When i get Events() there is usually more than one (as some of them are not immediately expired) Also the rule is triggert when temperature is changed without a new event being inserted. I could theoretically "mark" events that have been used, but I might run into problems when other rules are added that depend on the same events. Also it seems to be untidy to do so. For now I used this to get the "newest" event, but it seems to be very non-declarative to do it like that //most recent event Stack(size > 0, $event: pop, $event.value == 1) from collect( Event()) Are there any best practices especially for working with the "newest" event and with events + facts (as "states")? - Alex

12 years, 11 months

3
3
0 / 0

NPE exception when retracting fact in Drools 5.5.0.Final and 5.3.0.Final

by Bransford-Koons, Geoff

I'm trying to update our application from Drools 4.0.7 to Drools 5.5 (or 5.3 if that's better). All the rules compile and I am serializing the KnowledgeBase and reading it in upon application start-up. Inserting facts works find. Retracting can often return the NullPointerException shown below. That clip comes from a unit test that literally just inserts 10 "TestFact" objects and then tries to retract them one at a time. No rule firing happens, just insertion and retraction. I did try adding a rule firing in between the insert and retraction loops but it made no difference. These "TestFact" object don't actually trigger any rules if that matters. I've tried this with both the Drools 5.5.0.Final and 5.3.0.Final jars with the same results. Searches on the forum and on Google show this as a bug in 5.5.0.Final, but say it should work in 5.3.0.Final. It doesn't work on either for me. I am going to try some variations on this test, but it seems like this should work as-is. Any suggestions would be greatly appreciated. 2013-10-14 11:56:02,533 (ERROR) [AgdKnowledgeSession] caught exception trying to retract TestFact [name=testfact-0] java.lang.NullPointerException at org.drools.core.util.RightTupleIndexHashTable.remove(RightTupleIndexHashTable.java:365) at org.drools.reteoo.NotNode.retractRightTuple(NotNode.java:172) at org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:257) at org.drools.reteoo.EntryPointNode.retractObject(EntryPointNode.java:330) at org.drools.common.NamedEntryPoint.retract(NamedEntryPoint.java:542) at org.drools.common.NamedEntryPoint.retract(NamedEntryPoint.java:486) at com.teradata.agd.AgdKnowledgeSession.retract(AgdKnowledgeSession.java:134) at com.teradata.agd.AgCoreManager.executeFactEvent(AgCoreManager.java:279) at com.teradata.agd.AgCoreManager.executeRuleEngine(AgCoreManager.java:189) at com.teradata.agd.AgCoreManager.enqueue(AgCoreManager.java:259) at com.teradata.agd.AgCoreManager.retractFact(AgCoreManager.java:480) at com.teradata.agdtest.functional.FactInsertionAndRetractionTest.testFactInsertion(FactInsertionAndRetractionTest.java:50) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:84) at org.testng.internal.Invoker.invokeMethod(Invoker.java:714) at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:901) at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1231) at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:127) at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:111) at org.testng.TestRunner.privateRun(TestRunner.java:767) at org.testng.TestRunner.run(TestRunner.java:617) at org.testng.SuiteRunner.runTest(SuiteRunner.java:335) at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:330) at org.testng.SuiteRunner.privateRun(SuiteRunner.java:291) at org.testng.SuiteRunner.run(SuiteRunner.java:240) at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52) at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86) at org.testng.TestNG.runSuitesSequentially(TestNG.java:1224) at org.testng.TestNG.runSuitesLocally(TestNG.java:1149) at org.testng.TestNG.run(TestNG.java:1057) at org.testng.remote.RemoteTestNG.run(RemoteTestNG.java:111) at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:204) at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:175)

12 years, 11 months

3
2
0 / 0

using eval(function(this))) in rule LHS

by Elran Dvir

Hi all, I have the a drl similar to the following drl: package com.checkpoint.correlation.impl.drools.package1; import java.util.Date import java.util.HashMap import com.checkpoint.correlation.impl.drools.Log import com.checkpoint.correlation.impl.drools.CorrelatedEvent global com.checkpoint.correlation.server.EventsHandler externalEventsHandler; function boolean filter(Log log) { return (log.fieldsMap.get("port")!= null && (!log.fieldsMap.get("product").toString().equals("-1"))); } function String calcSeverity(Log log) { return "High"; } declare Log @role( event) end declare CorrelatedEvent @role( event) @expires( 10s ) end // this rule will create a "Port Scan" event if none exist for this group-by values rule "Create Port Scan Event" dialect "java" no-loop when $log : Log(eval(filter(this))) accumulate(Log(eval(filter(this)) , this after[0s,5s] $log, fieldsMap.get("src") == $log.fieldsMap.get("src") , fieldsMap.get("dst") == $log.fieldsMap.get("dst"), $port : fieldsMap.get("port")); $portSet : collectSet($port); $portSet.size > 2 ) accumulate( CpLog(eval(filter(this)), this after[0s,5s] $log, fieldsMap.get("src") == $log.fieldsMap.get("src") , fieldsMap.get("dst") == $log.fieldsMap.get("dst"), $portSet.contains(fieldsMap.get("port")), $marker : fieldsMap.get("marker")); $markerSet : collectSet($marker)) not CorrelatedEvent(getId() == "portScan" , groupByFieldsMap.get("src") == $log.fieldsMap.get("src") , groupByFieldsMap.get("dst") == $log.fieldsMap.get("dst")) then System.out.println("port scan"); System.out.println(drools.getRule().getId()); CorrelatedEvent $ce = new CorrelatedEvent("portScan"); $ce.groupByFieldsMap.put("src", $log.fieldsMap.get("src")); $ce.groupByFieldsMap.put("dst", $log.fieldsMap.get("dst")); insert($ce); HashMap<String,Object> fieldsMap = new HashMap<String,Object>(); fieldsMap.put("src",$log.fieldsMap.get("src")); fieldsMap.put("dst",$log.fieldsMap.get("dst")); fieldsMap.put("cu_rule_severity", calcSeverity($log)); fieldsMap.put("markers",$markerSet.toString()); externalEventsHandler.handleEvent(fieldsMap); end when I compile it, I am getting the error "Cannot use this in a static context". This is because the use of filter(this). I know that in this example, I can write my conditions inside the fact, but I have more complicated cases, so I prefer to use a function. So, how can I use a function with the fact being processed? Thanks!

12 years, 11 months

2
1
0 / 0

Ask about Drools, Business Rule (.brl file) and technical rule (.drl)

by Trong Hieu Tran

Hello Madam/ Sir I'm Trong-Hieu, I'm developer at Clearpath LLC. I'm stuck with drools guvnor and realy need your help please. We developed web application with drools rules - technical rules (.drl). Our project has a large of technical rule, one nice day, the customer would like to transfer all the technical rules to business rules (.brl files). I have searched on internet and can not find the right way to do. Please help! If you have any documents or reference links please show me. I heard about Drools guvnor 6 that it allows the user use Guide Editor to edit technical rule file (.drl), so if it is true, could I transform business rule to technical rule in drools 6? Please help me, I'm sorry to take your time. Thank you, Trong Hieu

12 years, 11 months

2
2
0 / 0

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

rules-users October 2013