creating .pkg from .drl
by Amit Kumar
Hi Folks,
I am trying to create a .pkg file (for probably faster loading) from a .drl
file
Does anybody has a code snippet which I can use. Am unable to find it in
javadocs.
Thanks
Amit
15 years, 10 months
KnowledgeAgent and OSGI
by mmarmol
Hi, I have managed to install Drools-core and Drools-compiler in my Equinox
osgi environment, I can compile rules and execute them just fine, I was just
wandering how to configure a KnowledgeAgent using
KnowledgeBuilderFactoryService and KnowledgeBaseFactoryService. I managed to
configure one but i am not able to reload rules when they change at runtime.
I have started ResourceChangeScannerService and
ResourceChangeNotifierService, changeset related to the rules file gets read
but no change gets implemented. An idea?
Here is the code:
ResourceFactory.getResourceChangeScannerService().start();
ResourceFactory.getResourceChangeNotifierService().start();
ServiceReference serviceRef = bc
.getServiceReference(ServiceRegistry.class.getName());
ServiceRegistry registry = (ServiceRegistry) bc.getService(serviceRef);
KnowledgeBuilderFactoryService knowledgeBuilderFactoryService = registry
.get(KnowledgeBuilderFactoryService.class);
KnowledgeBaseFactoryService knowledgeBaseFactoryService = registry
.get(KnowledgeBaseFactoryService.class);
ResourceFactoryService resourceFactoryService = registry
.get(ResourceFactoryService.class);
KnowledgeBuilderConfiguration kbConf = knowledgeBuilderFactoryService
.newKnowledgeBuilderConfiguration(null, getClass()
.getClassLoader());
KnowledgeBuilder kbuilder = knowledgeBuilderFactoryService
.newKnowledgeBuilder(kbConf);
ResourceFactoryService resource = resourceFactoryService;
kbuilder.add(resource.newFileSystemResource(filePath),
ResourceType.CHANGE_SET);
if (kbuilder.hasErrors()) {
System.out.println(kbuilder.getErrors());
throw new RuntimeException(kbuilder.getErrors().toString());
}
KnowledgeBaseConfiguration kbaseConf = knowledgeBaseFactoryService
.newKnowledgeBaseConfiguration(null, getClass()
.getClassLoader());
KnowledgeBase kbase = knowledgeBaseFactoryService
.newKnowledgeBase(kbaseConf);
kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());
KnowledgeAgentConfiguration aconf =
KnowledgeAgentFactory.newKnowledgeAgentConfiguration();
aconf.setProperty("drools.agent.scanDirectories", "true");
aconf.setProperty("drools.agent.scanResources", "true");
aconf.setProperty("drools.agent.newInstance", "false");
kagent = KnowledgeAgentFactory.newKnowledgeAgent( "CoreDroolsAgent",kbase,
aconf);
kagent.applyChangeSet(resource.newFileSystemResource(filePath));
Thanks in advance!
Cheers
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15 years, 10 months
Failed to read schema document when trying to transform from XML to DRL
by Chang Liu
Hi there,
Error message:
(null: 5, 77): schema_reference.4: Failed to read schema document 'drools.org/drools-5.0.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
I ran into this issue when experimenting a project that transforming the rules back and forth from DRL to XML with utility classes as documented in following link:
http://downloads.jboss.com/drools/docs/5.0.1.26597.FINAL/drools-expert/ht...
My code:
...
XmlPackageReader xmlReader = new XmlPackageReader(null);
StringReader sr = new StringReader(rulesInXml);
try {
PackageDescr packageDescr = xmlReader.read(sr);
DrlDumper drlDumper = new DrlDumper();
String drlString = drlDumper.dump(packageDescr);
}
catch (Exception ex) {
System.out.println(ex);
}
...
where string "rulesInXml" is the result xml string transformed from a valid .drl file. It looks like:
<?xml version="1.0" encoding="UTF-8"?>
<package name="com.sample"
xmlns="http://drools.org/drools-5.0"
xmlns:xs="http://www.w3.org/2001/XMLSchema-instance"
xs:schemaLocation="http://drools.org/drools-5.0 drools.org/drools-5.0.xsd">
<import name="com.sample.DroolsTest.Message" />
<rule name="Hello World">
<lhs><pattern identifier="m" object-type="Message" >
<field-constraint field-name="status">
<qualified-identifier-restriction evaluator="==">Message.HELLO </qualified-identifier-restriction>
</field-constraint>
<field-binding field-name="message" identifier="myMessage" />
</pattern>
</lhs>
<rhs> System.out.println( myMessage );
m.setMessage( "Goodbye cruel world" );
m.setStatus( Message.GOODBYE );
update( m );
</rhs>
</rule>
<rule name="GoodBye">
<lhs><pattern object-type="Message" >
<field-constraint field-name="status">
<qualified-identifier-restriction evaluator="==">Message.GOODBYE </qualified-identifier-restriction>
</field-constraint>
<field-binding field-name="message" identifier="myMessage" />
</pattern>
</lhs>
<rhs> System.out.println( myMessage );
</rhs>
</rule>
</package>
What did I miss here?
Moreover, the Drools 5.0 API's for XML support are poorly-documented. For example, the constructors of class "XmlPackageReader" has an arg of "SemanticModules" type which is not documented. :(
Any help would be highly appreciated!
Thanks,
Chang
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15 years, 10 months
Timers' Week :)
by nanic23
Alright... two more:
1. If a process suspends, do timers keep running/firing?
2. Let's say I have workItem_1 --> workItem_2 --> workItem_3 of which
"workItem_1" suspends the flow and "workItem_3" has a timer. After reloading
the StatefulKnowledgeSession and completing "workItem_1" and moving on do I
need to restart the timer for "workItem_3"?
I would like to mention some inconsistent behavior I have experienced:
- ksession.fireUntilHalt() is not starting the timers, instead
ksession.fireAllRules() DOES.
- ksession.halt() does not stop the timers (if that is the way I'm supposed
to stop them)
Any tips or personal experience will be very appreciated.
Thanks,
Nick.
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15 years, 11 months
Decision Tree input?
by Wilson O Ojwang
All,
Is there something in the works to support Decision Tree Inputs in
addition to Decision Table?
Regards
Wilson
15 years, 11 months
java.lang.NoSuchMethodError on every Action node
by Ana F Santos
Hi everyone.
I've been trying to use Drools for the past month, and sometimes I have
problems I can't guess anymore how to solve.
This time, every action I try to insert in a ruleflow, I receive a
java.lang.NoSuchMethodError. I'm even trying a really simple ruleflow with
just one simple action - like System.out.println("Test"); - and all I get
is a java.lang.NoSuchMethodError.
[
The stack trace:
java.lang.NoSuchMethodError:
br.com.pst.packages.ruleflows.Process_br_com_pst_packages_ruleflows_0.action0(Lorg/drools/spi/KnowledgeHelper;Lorg/drools/spi/ProcessContext;)V
at
br.com.pst.packages.ruleflows.Process_br_com_pst_packages_ruleflows_0Action0Invoker.execute(
Process_br_com_pst_packages_ruleflows_0Action0Invoker.java:20)
at
org.drools.workflow.instance.node.ActionNodeInstance.internalTrigger(
ActionNodeInstance.java:54)
at org.drools.workflow.instance.impl.NodeInstanceImpl.trigger(
NodeInstanceImpl.java:111)
at
org.drools.workflow.instance.impl.NodeInstanceImpl.triggerConnection(
NodeInstanceImpl.java:142)
at
org.drools.workflow.instance.impl.NodeInstanceImpl.triggerCompleted(
NodeInstanceImpl.java:128)
at
org.drools.workflow.instance.node.StartNodeInstance.triggerCompleted(
StartNodeInstance.java:49)
at
org.drools.workflow.instance.node.StartNodeInstance.internalTrigger(
StartNodeInstance.java:41)
at org.drools.workflow.instance.impl.NodeInstanceImpl.trigger(
NodeInstanceImpl.java:111)
at
org.drools.ruleflow.instance.RuleFlowProcessInstance.internalStart(
RuleFlowProcessInstance.java:16)
at org.drools.process.instance.impl.ProcessInstanceImpl.start(
ProcessInstanceImpl.java:185)
at
org.drools.workflow.instance.impl.WorkflowProcessInstanceImpl.start(
WorkflowProcessInstanceImpl.java:230)
at org.drools.common.AbstractWorkingMemory.startProcess(
AbstractWorkingMemory.java:1639)
at org.drools.common.AbstractWorkingMemory.startProcess(
AbstractWorkingMemory.java:1604)
at org.drools.impl.StatefulKnowledgeSessionImpl.startProcess(
StatefulKnowledgeSessionImpl.java:267)
at br.com.pst.packages.ServicePackages.main(
ServicePackages.java:99)
]
Actually, the beginning problem was with my project, with a process and
subprocess. The subprocess works fine, but the main process throws a
java.lang.NoSuchMethodError always on any node I put after a specific
RuleFlowGroup node. Everyting used to work before, but when I begin to
enlarge it, nothing seems to work anymore. And, as I told, I can't always
guess the exact problem as the thrown exceptions are very generic.
Hope anyone could help me!
Thanks a lot
ANA FLÁVIA FONSECA DOS SANTOS
Analista de Desenvolvimento de Software
PST Eletrônica S/A
Phone: +55 19 3787 6379
aflavia(a)pst.com.br
www.pst.com.br
www.positron.com.br
15 years, 11 months
KnowledgeAgent doesn't load dsl files and dslr file from a change-set correctly
by Pritham
I have a folder in classpath:
dsl/global.dsl
rules/section-A.dslr
rules/section-A/page-1.dslr
I create a knowledge base like this:
public KnowledgeBase createKnowledgeBase() throws DroolsParserException,
IOException {
KnowledgeBuilder knowledgeBuilder = KnowledgeBuilderFactory
.newKnowledgeBuilder();
knowledgeBuilder.add(ResourceFactory
.newClassPathResource("dsl/global.dsl"),
ResourceType.DSL);
knowledgeBuilder.add(ResourceFactory
.newClassPathResource("rules/section-A.dslr"),
ResourceType.DSLR);
knowledgeBuilder.add(ResourceFactory
.newClassPathResource("rules/section-A/page-1.dslr"),
ResourceType.DSLR);
if (knowledgeBuilder.hasErrors()) {
throw new RuntimeException(knowledgeBuilder.getErrors().toString());
}
KnowledgeBase knowledgeBase = KnowledgeBaseFactory.newKnowledgeBase();
knowledgeBase.addKnowledgePackages(knowledgeBuilder.getKnowledgePackages());
return knowledgeBase;
}
// code
knowledgeBase = createKnowledgeBase();
session = knowledgeBase.newStatefulKnowledgeSession();
// insert facts
session.fireAllRules();
session.dispose();
The above code works and I can get a unit test to work that processes rules
accordingly. I can see my dslr converting to a drl using the "drl viewer"
correctly (provided I temporarily place the dsl file in the same location
since expander doesn't accept a relative path).
The problem, however is when I use a change-set.xml and a KnowledgeAgent,
things don't work
code for loading via knowledgeAgent
public static KnowledgeBase loadKnowledgeBase() throws
DroolsParserException, IOException {
agent = KnowledgeAgentFactory.newKnowledgeAgent("msll agent");
agent.applyChangeSet(ResourceFactory.newClassPathResource("change-set.xml"));
return agent.getKnowledgeBase();
}
<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.xsd'
>
<add>
<resource source='classpath:dsl/' type='DSL' />
<resource source='classpath:rules/' type='DSLR' />
<resource source='classpath:rules/section-A/' type='DSLR' />
</add>
</change-set>
I get the following generic drools errors:
ERR 103] Line 4:0 rule 'rule_key' failed predicate:
{(validateIdentifierKey(DroolsSoftKeywords.RULE))}? in rule[7,0]: [ERR 101]
Line 7:0 no viable alternative at input 'import' in rule Con in rule
attribute
...
...
The rules are same, folder location is the same. I believe that drools has a
problem resolving path (expander global.dsl) from the dslr file when using a
KnowlegeAgent since in the earlier strategy, one could build a dsl into the
knowledgeBuilder directly from the classpath.
Pl suggest.
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15 years, 11 months
Implementing Timers With Drools Persistence Enabled
by nanic23
Hi All,
I was able to implement some timers and they behave as expected until I
enable persistence. Timers work (get triggered) when creating the
StatefulKnowledgeSession by kbase.newStatefulKnowledgeSession() but they do
NOT work (do not get triggered) when creating the StatefulKnowledgeSession
by JPAKnowledgeService.newStatefulKnowledgeSession(kbase, null, env);
I am calling ksession.fireUntilHalt() from within a new thread and all that.
The problem is not getting timers to work, as I have already accomplished
this, but the problem is rather getting them to work with persistence
enabled.
- Has anyone implemented timers while using (having enabled) persistence?
- Did you experience any problems such as timers not triggering?
- If so, have you found a work around you could share?
The timers are being implemented in ruleflow (DRF) and I'm using drools
5.1.0
Any comments are welcome.
Thanks,
Nick.
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15 years, 11 months
