March 2007 - rules-users - Jboss List Archives

PackageBuilder fail with java.lang.ExceptionInInitializerError

by Sergio Szychowski

Hi, when I try PackageBuilder builder = new PackageBuilder(); I running this in JbossEclipse, I can run the examples without trouble, but in a new project I get this error. Exception in thread "main" java.lang.ExceptionInInitializerError at org.drools.compiler.PackageBuilder.loadCompiler(Unknown Source) at org.drools.compiler.PackageBuilder.<init>(Unknown Source) at org.drools.compiler.PackageBuilder.<init>(Unknown Source) at nova.common.session.GenericSession.configTaskData(GenericSession.java:220) at nova.common.session.GenericSession.initSession(GenericSession.java:73) at nova.test.entity.client.TestFrameTask.initSession(TestFrameTask.java:268) at nova.common.task.FrameTask.init(FrameTask.java:12) at nova.test.entity.client.TestFrameTask.init(TestFrameTask.java:90) at nova.common.task.SimpleLauncher.launchTask(SimpleLauncher.java:65) at nova.common.task.SimpleLauncher.main(SimpleLauncher.java:25) Caused by: org.apache.commons.logging.LogConfigurationException: org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException) (Caused by org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException)) at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:543) at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235) at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:209) at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351) at org.apache.commons.jci.compilers.EclipseJavaCompiler.<clinit>(EclipseJavaCompiler.java:52) ... 10 more Caused by: org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException) at org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:397) at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:529) ... 14 more Caused by: java.lang.NullPointerException at org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:374) ... 15 more Greetings

17 years, 1 month

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problem in comparing two dynamic values inside

by Sikkandar Nawabjan

Your logic in the condition is wrong.

17 years, 1 month

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'from accumulate' doesn't work on multiple columns?..

by Olenin, Vladimir (MOH)

This is as a follow up for the previous question.... It looks like I made a wrong assumption that 'accumulate' can work on multiple columns: Integer ( intValue > 0) from accumulate ( Record ( f1 == $f1, f2 < 10, $value1 : value ) Record ( f1 == $f1, f2 >= 10, $value2 : value ) Init ( int sum = 0; ), Action ( sum += $value1 - $value2 ), Result ( new Integer (sum) ) ) I'm getting an error ('then' is expected or smth like that at the point where the second 'Record' is defined) and the only way to remove the error is to declare one and only one Column constraint... So, it is not possible then to use multiple columns in 'accumulate'? If not, then it would be even more interesting to get some idea on how to approach the kind of problem I mentioned in the previous post..... Thanks, Vlad

17 years, 1 month

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'distinct' keyword?.... or an alternative... here is an example

by Olenin, Vladimir (MOH)

Hi, I ran into the situation when I need the functionality similar to 'distinct' keyword from SQL, ie I have a set of facts: Record (f1 = 1, f2 = 1, value = 4) Record (f1 = 1, f2 = 2, value = 1) Record (f1 = 1, f2 = 13, value = 2) Record (f1 = 1, f2 = 14, value = 5) Record (f1 = 2, f2 = 5, value = 7) Record (f1 = 2, f2 = 6, value = 3) Record (f1 = 2, f2 = 15, value = 8) Record (f1 = 2, f2 = 16, value = 9) .. etc And I need to calculate two sums _within the same 'f1' field_ for each unique 'f1' field and compare them: - $sum1: f2 < 10 - $sum2: f2 >= 10 - If $sum1 > sum2 then do something One of the ways to do that is to iterate through all unique f1 fields and calculate two sums. Here is where I thought 'distinct' keyword might have helped. Otherwise I need to assert another set of 'unique f1 fields' facts to iterate through: Rule XXX When Distinct Record ( $f1 : f1 ) Integer ( intValue > 0) from accumulate ( Record ( f1 == $f1, f2 < 10, $value1 : value ) Record ( f1 == $f1, f2 >= 10, $value2 : value ) Init ( int sum = 0; ), Action ( sum += $value1 - $value2 ), Result ( new Integer (sum) ) ) Then System.out.println("HURRAH!"); End I realize that one would not be able to bind any other variable from 'distincted' record other than those in the constraint fields, but this is not really required..... The only other solution for the problem above I managed to come up with is to accumulate the sums in a helper object, which has the buckets for each unique f1 value and do the eval after 'accumulate on testing if any of the buckets is a positive number. In other words, not to iterate through each unique 'f1', but iterate through all records and put the sum to the correct bucket: Helper.getBucket($f1).addValues($value1, value2). The other thing is what Edson mentioned some time ago: DROOLS does not allow internally for the same fact to be selected twice in a tuple. Surprisingly one of the recent tests I ran against 3.1M did actually select the same fact in the tuple (see the post from last Friday, March 02: "confused again.... - why it selects all possible combinations"). Not sure if it's a bug or an extended functionality... but this kind of thing should be helpful in here.... Are there any other approaches I missed?... What's the best one in terms of performance? Thanks, Vlad

17 years, 1 month

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column binding vs field binding - any performance implications?

by Olenin, Vladimir (MOH)

Hi, I wonder if there are any performance implications of choosing column binding vs field binding (I'll be using bound variable in eval). Eg, in such case: Record($field : field) eval ( $field.equals("xxx") ) vs $r: Record() eval ( $r.field.equals("xxx") ) Does it start to make difference only when some significant number of variable get bound? Thanks, Vlad

17 years, 1 month

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Help - speaker needed

by Steven Williams

Hi all, I need to organise a speaker for a seminar in Melbourne (Australia) around Business Rules. We are specifically interested in hearing about projects that have implemented using rules engines (as opposed to hearing about rules engine internals or theory). So if you have used rules engines (it doesn't have to be Drools/JBoss Rules) on a project and will be in Melbourne in the next few months and would be interested in speaking, please let me know as soon as possible. thanks a lot Steve -- Steven Williams Supervising Consultant Object Consulting Office: 8615 4500 Mob: 0439 898 668 Fax: 8615 4501 stevenw(a)objectconsulting.com.au www.objectconsulting.com.au consulting | development | training | support our experience makes the difference

17 years, 1 month

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RE: [rules-users] what's wrong with this rule?...

by Olenin, Vladimir (MOH)

Edson, Thanks for the tip - you are right - 'return' keyword should not be used - got to this one by trial & error just before I saw your reply :). The problem is that the only 'public' docs available on the new functionality (Wiki 3.1 release notes: http://wiki.jboss.org/wiki/Wiki.jsp?page=3.1M1ReleaseNotes) gives the example of 'accumulate' keyword where 'return' keyword IS used in the 'result' section! So, I guess this needs to be updated?.. Interestingly, "eval ($count < 4)" DOES work correctly and as expected! So, I guess that's an extra feature? :) Thanks for the example on how to avoid eval altogether - already tried it and it works like a charm! Nice functionality! Would it be worth it to include this in Wiki? Thanks, Vlad -----Original Message----- From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Edson Tirelli Sent: 06 March 2007 16:19 To: Rules Users List Subject: Re: [rules-users] what's wrong with this rule?... Vlad, You should not use the "return" keyword and the ";" inside the result block as it is implicit. Also, remember that anything inside eval() is pure java code, so you cant do $count < 4 if $count is an Integer object. Finally, try to always avoid eval() when writing rules. Try something like: *rule* "FG.23C" *when* *exists* Record( $psc : psc == "323", pa == "7[0-9]*", sa == "F39040" |== "F38010" |== "F38090" ) $count : Integer( intValue < 4 ) *from* *accumulate *( Record( psc == "323", pa *matches* "8[0-9]995", sa *matches* "F390[4-8][2-5]" ), init ( *int* count = 0; ), action( count += count; ), result( *new* Integer(count) ) ) *then* System.out.println( "rule FC.23C has failed" ); System.out.println(); *end* ** Please, let me know if it works. []s Edson Olenin, Vladimir (MOH) wrote: > Hi, > > I have the following rule: > > *rule* "FG.23C" > > *when* > > *exists* > > Record( $psc : psc == "323", > > pa == "7[0-9]*", > > sa == "F39040" > > |== "F38010" > > |== "F38090" ) > > $count : Integer() *from* *accumulate *( > > Record( psc == "323", > > pa *matches* "8[0-9]995", > > sa *matches* "F390[4-8][2-5]" ), > > init ( *int* count = 0; ), > > action( count += count; ), > > result( *return* *new* Integer(count); ) > > ) > > *eval* ($count < 4 ) > > *then* > > System.out.println( "rule FC.23C has failed" ); > > System.out.println(); > > *end* > > * * > > And for some reason I can't compile correctly: I'm getting the > following error: > > org.drools.rule.InvalidRulePackage: Rule Compilation error This method > must return a result of type Integer Syntax error on token "(", ; > expected Syntax error on token ")", delete this token > > at org.drools.rule.Package.checkValidity(_Package.java:367_) > > at > org.drools.common.AbstractRuleBase.addPackage(_AbstractRuleBase.java:244_) > > at moh.ohfs.rules.RulesTest.readRule(_RulesTest.java:70_) > > at moh.ohfs.rules.RulesTest.main(_RulesTest.java:22_) > > All brackets seem to be matching.... This happens on 3.1M build. > > Thanks, > > Vlad > >------------------------------------------------------------------------ > >_______________________________________________ >rules-users mailing list >rules-users(a)lists.jboss.org >https://lists.jboss.org/mailman/listinfo/rules-users > > -- Edson Tirelli Software Engineer - JBoss Rules Core Developer Office: +55 11 3124-6000 Mobile: +55 11 9218-4151 JBoss, a division of Red Hat @ www.jboss.com _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

17 years, 1 month

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what's wrong with this rule?...

by Olenin, Vladimir (MOH)

Hi, I have the following rule: rule "FG.23C" when exists Record( $psc : psc == "323", pa == "7[0-9]*", sa == "F39040" |== "F38010" |== "F38090" ) $count : Integer() from accumulate ( Record( psc == "323", pa matches "8[0-9]995", sa matches "F390[4-8][2-5]" ), init ( int count = 0; ), action( count += count; ), result( return new Integer(count); ) ) eval ($count < 4 ) then System.out.println( "rule FC.23C has failed" ); System.out.println(); end And for some reason I can't compile correctly: I'm getting the following error: org.drools.rule.InvalidRulePackage: Rule Compilation error This method must return a result of type Integer Syntax error on token "(", ; expected Syntax error on token ")", delete this token at org.drools.rule.Package.checkValidity(Package.java:367) at org.drools.common.AbstractRuleBase.addPackage(AbstractRuleBase.java:244) at moh.ohfs.rules.RulesTest.readRule(RulesTest.java:70) at moh.ohfs.rules.RulesTest.main(RulesTest.java:22) All brackets seem to be matching.... This happens on 3.1M build. Thanks, Vlad

17 years, 1 month

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Dynamic rule creation

by seeker

How can I create a rule on the fly ? I have some rules working, and I want the user let chance some values in the conditions. Say I have somthing like rule "somerule" when foo : Foo ( a : level -> ( a.floatValue() > 20.0) ) then ... I want change the "20.0" afterwards to some other value. Is this possible ? What do I have to do for that? The drools javadocs are not that much helpful on that matter. Do I have to remove the rule, create a new one and insert it into the agendagroup ? Or can I modify a rule? What other things does somthing like this imply? (Do I have to reassert all facts or something?) The worst what I can think of is writing all rules including the modified one into a new file and start reading the rules-file, creating the workingmemory and building my facts once again. IS there another way? -- View this message in context: http://www.nabble.com/Dynamic-rule-creation-tf3354961.html#a9330444 Sent from the drools - user mailing list archive at Nabble.com.

17 years, 1 month

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DSL - Calling Java Method , Eval functions

by kingston

Is it possible to write a rule in DSL to check for a value that is returned by a calls to a java method in the Condition part ? Are there any sample codes for using eval in DSL Syntax or for calling java methods ? -- View this message in context: http://www.nabble.com/DSL---Calling-Java-Method-%2C-Eval-functions-tf3307... Sent from the drools - user mailing list archive at Nabble.com.

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rules-users March 2007