app-dev 'toe in water' help please
by dhartford
Hey all,
I'm trying to dip some toes into the water with Drools, and have an
application that would be a good start but having some understanding/lacking
an appropriate example issue.
The application context, let's say, is Mortgages, and already using the
Mortgage rules that are stored in a running instance of Guvnor.
Going back to 'toe in water', lets assume that all 'facts' are loaded on
call (so nothing is pre-loaded, all data to run a rule is supplied at the
time the rule is called). This is to make it easier to get started without
jumping all-in just yet ;-)
Using the mortgage business rule 'CreditApproval' that is already loaded
into Guvnor, I can see passing the Application object, with the creditRating
field/fact to a rule.
However, instead of populating and returning a loanApplication object, how
would I return just the decision/end result of a rule if it was only one
value (the approved/not approved decision) from the java app? KnowledgeBase
is loaded from the java app, but struggling with StatefulKnowledgeSession
versus StatelessKnowledgeSession and how to simply get back the rule
decision value (again, preferably without a specific object if it is only
one value)?
I'm also looking to only fire/execute one rule at a time for now until we
get comfortable - any help for an app developer trying to ease their way
into drools?
Sorry if I not overly clear, still trying to learn the appropriate
terminology :-)
-Darren
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2 weeks, 4 days
drools-solver results question
by Andrew Waterman
Hello,
I'm starting to work with the drools-solver to help on a gaming
project. Basically, we have a game that works in two modes: 1) a
competitive game where humans (or agents) compete with one another on
a well defined game board to achieve 24 points by using three (or
four) agricultural development tokens. 2. A puzzle, where all 4
players work cooperatively to create an equitable solution, where all
4 players win with at least 24 points by means of our agricultural
development tokens.
I am starting to work with drools-solver to address the puzzle part of
our game. Basically, we are interested in having the solver do two
things for us: a) find the optimal solution for our game/puzzle,
based upon our requirements [this part seems quite straightforward]
and b) getting the total number of solutions that satisfy our
constraints. We would like, as well, to be able to inspect these
other, sub-optimal, solutions, in order to explore our game and puzzle
further. From my reading of the "Solver" API , it looks like we will
only be able to get the optimal solution. Does anyone have any
suggestions for a workaround in this case? Or is there some
functionality in the solver that I am missing?
I look forward to your feedback.
best wishes,
Andrew
---------------------------------
Andrew Waterman
San Cristóbal de las Casas, Chiapas, Mexico
1 month, 2 weeks
Need help with setFocus
by new2drools
Hi All,
Need some help with understanding setFocus.
I have the following use case:
if (condition1) {
if (condition2) {
} else if (condition3) {
} else if (condition 4) {
}
}
if (condition5) {
if (condition2) {
} else if (condition3) {
} else if (condition 4) {
}
}
I created 3 rules (rule2, rule3, rule4) for checking condition2, condition3,
condition4 and
created 1 agenda group (groupX) for them.
I created 2 rules (rule1, rule5) for checking condition1, condition5 and
created 1 agenda group(groupY) for them.
rule "rule1"
agenda-group "groupY"
when
//
then
drools.setFocus("groupX");
end
rule "rule3"
agenda-group "groupX"
activation-group "someActiveGroup"
when
//
then
//
end
>From the java code:
ksession.getAgenda().getAgendaGroup("groupY").setFocus();
Problem: The first time, drools.setFocus("groupX") is invoked, I see that
it's working fine. rule2 or rule3 or rule4 get triggered. But, the SECOND
time that drools.setFocus("groupX") is invoked, I don't see that any rule in
agenda-group groupX is being invoked...even though one of the rule's LHS
explicitly matches...thinking that the activation-group is cancelling all
the activation's (after one rule in that activation group is fired), I even
removed the activation-group statement. But, it didn't help...ideally, I
would like to bunch rule2, rule3, rule4 in one activation group.
Can you please let me know as to why the second invocation of setFocus is
not working? I even tried to remove everything in LHS of rule2/3/4, to see
if the second invocation would work...it doesn't...
Thanks!!
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2 months, 1 week
conways game of life
by Mark Proctor
For anyone looking for a good and complex example on how to write rules
properly, please look at Conways Game of Life in drools-examples, for
extra bonus points compare it to the old version in M1. You'll see
nearly all the logic is moved from java to the drl and we have removed
the need for nested objects by using objects relaitionally, which also
allows us to exploit cross products to drive the application.
Mark
6 months
How to read XML using XMLPackageReader-Drools-compiler.5.2.1.final?
by Praveen
Hi,
I am using Drools-compiler.5.2.1.final.
I am trying to convert an drl to xml and vice versa using DrlParser,
DrlDumper, XMLPackageReader and XML Dumper.
Drl to XML conversion works fine but XML to Drl throws NPE.
I have placed the XML file under a folder called sample.
NPE is thrown at line 5..
Also attached is the exception.
Please suggest.
TIA.
Reader source = new InputStreamReader(
DroolsConversionHelper.class.getResourceAsStream(xmlFileName));
PackageBuilderConfiguration conf = new PackageBuilderConfiguration();
XmlPackageReader reader = new
XmlPackageReader(conf.getSemanticModules());
DrlDumper dumper = new DrlDumper();
//line 5 reader.read(source);
PackageDescr descr = reader.getPackageDescr();
String test = dumper.dump(descr);
System.out.println(test);
java.lang.NullPointerException
at
org.drools.xml.ExtensibleXmlParser.resolveSchema(ExtensibleXmlParser.java:696)
at
org.drools.xml.ExtensibleXmlParser.resolveEntity(ExtensibleXmlParser.java:622)
at
com.sun.org.apache.xerces.internal.util.EntityResolverWrapper.resolveEntity(Unknown
Source)
at
com.sun.org.apache.xerces.internal.impl.XMLEntityManager.resolveEntity(Unknown
Source)
at
com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaLoader.resolveDocument(Unknown
Source)
at
com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.findSchemaGrammar(Unknown
Source)
at
com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.handleStartElement(Unknown
Source)
Regards,
Praveen.
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11 years, 8 months
Spring, KnowledgeAgent, and Guvnor
by paulB
I'm having a problem connecting my KnowledgeAgent to a package in Guvnor.
I'm using Spring to instantiate the KnowledgeAgent. The agent initializes
perfectly well when I point to a local change-set that in-turn points to a
local rule. However, even though I have the same rule in a package in
Guvnor, the KnowledgeAgent fails with the following exception when I point
to the package's change-set in Guvnor:
The code at KnowledgeBaseImpl.java:148 is (using 5.3.0.Final):
Here is the simple rule in the Guvnor as returned by the URL for the package
source URL:
Here is the local change-set definition. The line that is commented is the
failing resource, whereas the local file resource works fine:
Guvnor is residing on a Tomcat server.
I could not find anything related to this on the forum. Thank you for any
hints.
-Paul
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11 years, 11 months
named query TasksAssignedAsPotentialOwner doesn't work with MySql db
by Frank Knoll
Hi,
When I add a task (having two potential owners) by calling the method
addTask followed by calling the method getTasksAssignedAsPotentialOwner of
org.jbpm.task.service.TaskClient I expect to receive a list of TaskSummaries
containing at least the previously added task. But I actually get an empty
list!
Here is my setup and possible solution:
I am using the trunk version of
./jbpm-human-task/src/main/resources/META-INF/orm.xml and a MYSQL database.
When calling addTask the Task table will be populated with a NULL
actualOwner_id.
The named query TasksAssignedAsPotentialOwner
"select new org.jbpm.task.query.TaskSummary(...t.taskData.actualOwner...)
from ... left join t.taskData.actualOwner ..." of orm.xml generates SQL
consisting of an inner join "inner join OrganizationalEntity user7_ on
task0_.actualOwner_id=user7_.id" which doesn't take the NULL actualOwner_id
correctly into account.
When I replace the named query TasksAssignedAsPotentialOwner with
"select new org.jbpm.task.query.TaskSummary(...actualOwner...) from ...left
join t.taskData.actualOwner as actualOwner ...", then the generated SQL
consists of an "left outer join OrganizationalEntity user2_ on
task0_.actualOwner_id=user2_.id" which takes the NULL actualOwner_id
correctly into account. So I get a List of TaskSummaries containing the
added task.
Is this a correct fix?
Cheers, Frank
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12 years
Error Inserting events into drools fusion stream
by Ayush
Hi All,
I'm trying to implement drools fusion into my app. The scenario of my app is
as follows:
- Facts will be received continuosly.
- On receving fact I'm generating a new event and adding it into a new
working memory entry point stream. Also I'm adding facts into session coz
I'll be updating them.
- I need to apply rules on continuous stream of events.
- I've not used any camel + spring or pipeline. Are these mandatory to use?
For 1st fact everything works fine but when I receive 2nd fact I'm getting
Now when I'm trying to get entry point on receive of 2nd alarm I'm getting
org.drools.RuntimeDroolsException: Unexpected exception executing action
org.drools.reteoo.PropagationQueuingNode$PropagateAction@9ff411 Caused by:
java.util.concurrent.RejectedExecutionException.
On debug I found that the above exception is coming when I'm calling
session.getWorkingMemoryEntryPoint("MyStream"); Can anyone please help me
that how should I insert facts and events into working memory?
I'd invested ample amount of time searching for this but I'm empty handed.
Guys please help this is very urgent for me. Thanks in anticipation
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12 years, 1 month
Date equal comparison fails - don't understand why
by Saloojee, Karim
Hi
I am comparing SimpleAccount( dateAccountOpened == "5-Feb-2011")
where dateAccountOpened is "Sat Feb 05 00:00:00 GMT+02:00 2011" (if you
call toString()). The equal comparator fails (==) but the greater than
comparator passes (>) which I don't understand.
I feel I am missing something obvious here, but I have no idea what it
is.
rule "Test date equality"
when
$acc : SimpleAccount( dateAccountOpened == "5-Feb-2011")
then
System.out.println("Expected and found an account opened
on 5-Feb-2011: " + $acc);
end
rule "Some dates are more equal than others"
when
$acc : SimpleAccount( dateAccountOpened > "5-Feb-2011")
then
System.out.println("Unexpected match: " +
$acc.getDateAccountOpened());
end
Regards,
Karim
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12 years, 4 months
