[rules-users] Drools and jBPM integration

[Fabian Weisensee]

Well, I'm sorry if this was a dumb question. I'm writing my master 
thesis about serviceoriented architectures and this drools/jbpm project 
is only a very tiny part of it, so I don't have time to dig so deeply 
into this topic. And I thought I could rely on the only official 
documentation for the jbpm/drools integration.
But thank you very much for you answer. I'll try that tomorrow (already 
11pm here).

--Fabian

Mark Proctor schrieb:
> Fabian Weisensee wrote:
>> Yes, thanks for your help. I'll try your suggestion for #2.
>>
>> I resolved the deployment problem by myself. It was just a mistake 
>> with the JBoss ESB deploying...
>>
>> But now I have another problem. The rule file is found, but there seem 
>> to be some problems with the parser.
>>
>> The FireRulesActionHandler class from the jbpm wiki uses the following 
>> code:
>> RuleBaseImpl ruleBase = new RuleBaseImpl();
>> ruleBase.addPackage(pkg);
> You should read the Drools docuemtation, heck every example we have 
> shows how to do this, and every example will show
> RuleBase ruleBase = RuleBaseFactory.newRuleBase()
> ruleBase.addPackage( pkg )
> 
> Where the pkg is created from the PackageBuilder class, again this is 
> all documented with full examples. What you are using, and someone 
> wrongly documented, was an internal implementation class, you should be 
> using the interface.
>>
>> But the RuleBaseImpl class doesn't seem to be part of drools anymore. 
>> I looked at the javadocs to find a replacement. I've found the 
>> RuleBaseLoader class which looked like what I needed. I replaced the 
>> two lines with this:
>> RuleBaseLoader rbl = RuleBaseLoader.getInstance();
>> RuleBase ruleBase = rbl.loadFromReader(reader);
>> ruleBase.addPackage(pkg);
>>
>> but when I run this I get the following error:
>>
>> ERROR [GraphElement] action threw exception: Unable to parser Reader
>> java.lang.RuntimeException: Unable to parser Reader
>>     at org.drools.compiler.DrlParser.getParser(DrlParser.java:209)
>>     at org.drools.compiler.DrlParser.parse(DrlParser.java:60)
>>     at 
>> org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:165) 
>>
>>     at 
>> org.drools.compiler.RuleBaseLoader.loadFromReader(RuleBaseLoader.java:38)
>>     at 
>> rechnung.kontrolle.FireRulesActionHandler.readRule(FireRulesActionHandler.java:92) 
>>
>>     at 
>> rechnung.kontrolle.FireRulesActionHandler.execute(FireRulesActionHandler.java:49) 
>>
>>
>> Of course I thought my rule file would be syntacticaly incorrect, but 
>> even this rule file didn't work:
>>
>> package rechnung.kontrolle
>>
>> rule "test rule 1"
>>     when
>>     then                System.out.println("rule fired!");   end
>>
>> What am I doing wrong? Is RulesBaseLoader the right class?
>> Are there any other Informations about integrating jBPM and Drools?
>>
>> --Fabian
>>
>>
>>
>> Aziz Boxwala schrieb:
>>> Fabian,
>>>
>>> Response to #1: I believe the rule file needs to reside in the root 
>>> directory of the archive/directory of the example application. I have 
>>> not tried that out so not sure.
>>>
>>> With Drools 4.0.x, you have the option of having your rules be 
>>> located in the BRMS.
>>>
>>> Response to #2: You should be able to do so using one decision-node. 
>>> Associate the rule action handler with either the Before Signal or 
>>> Node Enter event and specify your decision conditions on the 
>>> transitions out of that node..
>>>
>>> --Aziz
>>>
>>> ----- Original Message ----
>>> From: Fabian Weisensee <fabian at weisensee.net>
>>> To: rules-users at lists.jboss.org
>>> Sent: Monday, November 12, 2007 7:35:02 AM
>>> Subject: [rules-users] Drools and jBPM integration
>>>
>>> Hi there
>>>
>>> I have some questions concerning Drools and jBPM integration.
>>> I know there is this wiki page:
>>> http://wiki.jboss.org/wiki/Wiki.jsp?page=JbpmAndDrools
>>> but first it's not really detailed and second does it seem to be 
>>> outdated.
>>>
>>> 1) I changed the FireRulesActionHandler from the wiki to reflect the
>>> API-changes, that at least it's compileable. In the jBPM process
>>> definition the rule file is simply passed as parameter like this:
>>> "/Shipper.drl". To which directory does this relative path apply? So
>>> where do I have to deploy this rule file? I tried several locations in
>>> the application server, but even with an absolute path every time
>>> FireRulesActionHandler tries to read the rule it crashes:
>>>
>>> ERROR [GraphElement] action threw exception: null
>>> java.lang.NullPointerException
>>>     at java.io <http://java.io.Re>.Reader.<init>(Unknown Source)
>>>     at java.io <http://java.io.In>.InputStreamReader.<init>(Unknown 
>>> Source)
>>>     at
>>> rechnung.kontrolle.FireRulesActionHandler.readRule(FireRulesActionHandler.java:83) 
>>>
>>>     at
>>> rechnung.kontrolle.FireRulesActionHandler.execute(FireRulesActionHandler.java:50) 
>>>
>>>
>>> 2) As I understood the example in the wiki you have to create a node
>>> which executes the rule and then a decision-node which routes the
>>> process flow according to the rule results.
>>> Is it possible to do this with just one node?
>>> But perhaps I should ask this at the jBPM forums.
>>>
>>> Every help would be appreciated. Thanks in advance.
>>>
>>> Fabian Weisensee
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>>> rules-users at lists.jboss.org <mailto:rules-users at lists.jboss.org>
>>> https://lists.jboss.org/mailman/listinfo/rules-users
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