Resuming a simple process involving human task
by Touma
Hi all,
For the past few weeks I've been trying to get a simple drools flow example
involving human tasks up and running. I've done quite a bit to the point
that my session, process, task and workitems are being persisted in the
database. Here is what my flow looks like:
Start -> Ruleflow -> Decision node -> Human Task -> Printing Node -> End
The work item handler for the Human task simply performs the task of
persisting the Task instance. After reaching the Human Task, the flow stops
and the state is persisted. But how would I go about restarting/resuming the
flow so that the 'Printing node' is reached? I've tried using the
loadStatefulKnowledgeSession(sessionId) to load the session but querying the
list of all the processes for the given session returns an empty list. Ditto
with the list of all the process events. I have all the ID's with me
(workitem, process, task, session) but am pretty confused as to how these
can be put to use to resume my suspended workflow.
Any pointers would be much appreciated. TIA.
Peace,
/T\
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14 years, 1 month
Chained Rules
by djb
Hi all,
I know there are some basic ways to chain rules together, by setting flags
in consequences that are checked in the conditions of other rules...
but in a large system based on rule templates, where thousands of rules are
generated, it is not feasible to chain rules in this manner, especially when
they are chained in a somewhat arbitrary fashion
(eg. True if Rule 130 AND Rule 200 AND Rule 480 fire)
has anyone had this situation before? would I need to execute this as a
post-processing step? or, is there any design pattern that will allow rules
to be chained, preferably in a manageable way?
regards,
Daniel
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14 years, 2 months
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
14 years, 3 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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14 years, 3 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
14 years, 4 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
14 years, 4 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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14 years, 4 months
