Drools 5 PseudoClock with StatelessKnowledgeSession
by Ben Scott
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I'm wanting to use the date-effective and date-expiry rule metadata to add date specific rule variants within my app. To test these I was planning on using the pseudo clock and setting the expected date prior to executing the rules within a StatelessKnowledgeSession. I can set the clock easily enough, but can't understand why the getSessionClock() method is missing? It's on the StatefulKnowledgeSession, but not on the Stateless.
I'm initialising the session like this:
SessionConfiguration sessionConfiguration = new SessionConfiguration();
sessionConfiguration.setClockType( ClockType.PSEUDO_CLOCK );
StatelessKnowledgeSession session = _testKnowledgeBase.newStatelessKnowledgeSession(sessionConfiguration);
The only thing I could think of to set the pseudo clock was to write a command something like:
private static class SetPseudoClockCommand implements org.drools.process.command.Command<Boolean> {
public Boolean execute(ReteooWorkingMemory session) {
// Set the clock to the current date
pseudoSessionClock.advanceTime(new DateTime().getMillis(), TimeUnit.MILLISECONDS);
// Add a couple of days
pseudoSessionClock.advanceTime(2, TimeUnit.DAYS);
return true;
}
}
But this doesn't appear to take any effect whilst rules are running.
Is there another way to get programmatic access to the session clock, or some better way of changing the underlying date prior to rule execution?
Ben.
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14 years, 8 months
Persistence of events
by Maciej Prochniak
Hello,
Is it possible to persist events (from drools fusion) with default jpa
mechanism? When I try to do this 'just like that' I get exception
like
org.drools.common.DefaultFactHandle incompatible with
org.drools.common.EventFactHandle
It seems that session marshaller is not really aware of certain objects
being events, not facts.
The code I try is more or less like:
UserTransaction ut = ...
StatefulKnowledgeSession session = JPAKnowledgeService
.newStatefulKnowledgeSession(kbase, null, env);
ut.begin()
session.insert(e1);
ut.commit();
StatefulKnowledgeSession sessionPersisted =
JPAKnowledgeService.loadStatefulKnowledgeSession( session.getId(),
kbase, null, env );
ut.begin()
sessionPersisted.insert(e2); (*) <- fails
ut.commit();
When I use session instead of sessionPersisted - it works fine, when
e2 is a fact, not an event - it also works
I know that it may be awkward to persist events which have time
limitations, but I want to use time limits in rules which are like few
days - so I want to have some persistence in case of server shutdown.
I would be grateful for any comment,
br,
maciek prochniak
14 years, 9 months
Log4j in the rules?
by granz＠MIT.EDU
Hi,
Is it possible to use Log4j inside the rules (RHS)?? (drl file)
Thanks,
Fabrice
14 years, 9 months
Drools-Fusion : Inserting an Event in to an "entry-point" stream in the RHS of a rule?? Pls help
by Chetan Mahadev
Hi
Can we insert an Event in the RHS part of a rule to an entry-point?
basically i am trying to do this. Pls let me know if this is possible? if
not any alternative approaches? Any example would be useful pls
declare TransactionEvent
@role( event )
end
$tmp : TestClass()
$tmp.message == "TRUE"
then
TransactionEvent ev1 = new TransactionEvent (); // This should be
inserted in to an entry-pont "Temporal Reasoning" stream
ev1.setMessage("Temporal Reasoning")
insert (ev1) to entry-point "Temporal Reasoning"
end
rule "Temporal Reasoning"
$tmp : TransactionEvent ( message== "Temporal Reasoning") from entry-point
"Temporal Reasoning"
then
System.out.println("Rule fired due to entry point ");
end
Regds
Chetan
14 years, 10 months
How to Access and Execute Rules from Database
by Ashish Soni
Hi All ,
I am able to configure oracle database in drools but now i am not able to
find how can i load rules from the DB and execute them , I gone through the
documentation but not able to get much information or might be i am missing
something.
If any one can provide me a example or some pointer ,hints then it would be
helpful.
Regards,
Ashish
14 years, 11 months
unable to determine operator for symbol [before]
by vladimiro
Hi all,
I'm building a KnowledgeBase with KnowledgeAgent and a precompiled
rule package. When the package contains a rule using temporal operators
such "after" or "before" I get the exception listed at the end of this
message.
I'm using the latest version of drools 5 and my runtime configuration
includes the following libraries:
* drools-core - the rule engine itself.
* drools-api
* mvel2-2.0.10
* joda-time-1.6
the rule causing such a behaviour is:
rule 'Test2'
dialect 'mvel'
when
u1:UserType( firstName=="UserA" )
lie:UserEventType( event=="Login", user.id==u1.id)
loe:UserEventType(event=="Logout", user.id==u1.id, this before lie)
then
Message msg = new Message();msg.setText("Test2
fired");driver.getMessages().add(msg);
end
java.lang.RuntimeException: KnowledgeAgent exception while trying to
deserialize KnowledgeDefinitionsPackage
at
org.drools.agent.impl.KnowledgeAgentImpl.rebuildResources(KnowledgeAgentImpl.java:418)
at
org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet(KnowledgeAgentImpl.java:120)
at
org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet(KnowledgeAgentImpl.java:109)
at
info.vladimiro.tesi.peservice.KnowledgeBaseService.<init>(KnowledgeBaseService.java:94)
at
info.vladimiro.tesi.peservice.KnowledgeBaseService.getInstance(KnowledgeBaseService.java:65)
at
info.vladimiro.tesi.peservice.PEListener$KBTask.run(PEListener.java:35)
at java.util.TimerThread.mainLoop(Timer.java:512)
at java.util.TimerThread.run(Timer.java:462)
Caused by: org.drools.RuntimeDroolsException: unable to determine
operator for symbol [before]
at
org.drools.base.evaluators.Operator.determineOperator(Operator.java:71)
at org.drools.base.evaluators.Operator.readResolve(Operator.java:106)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at
java.io.ObjectStreamClass.invokeReadResolve(ObjectStreamClass.java:1033)
at
java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1728)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1305)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:348)
at org.drools.base.BaseEvaluator.readExternal(BaseEvaluator.java:53)
at ...
Can someone help? Thanks in advance.
Vladimiro Corsi
15 years, 1 month
StatefulKnowledgeSession Vs StatefulSession
by DeepakA
I used a KnowledgeBuilder ro read the resources (DSL & DSLR files)
Then created a KnowledgeBase and created a StatefulKnowledgeSession out of
the KnowledgeBase.
The StatefulKnowledgeSession was used to start the process and fire all
rules.
Then I realized I was not able to access the RuleBase from
StatefulKnowledgeSession.
So, now I create a RuleBase, then a PackageBuilder, add the resources to the
packageBuilder, then add the
package to the RuleBase and create a StatefulSession out of the RuleBase.
This statefulsession is used to start the process and fire all rules.
Can someone explain to me whats the difference in the above 2 methods of
firing the rules.
Whats the difference between StatefulKnowledgeSession & StatefulSession.
--
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15 years, 2 months
[Urgent] Error in ontext assist in DSLR Editor
by hamza bakkali
Hi All,
I have been using drools 4 for couple of months now and I am starting to get
the hang of it. We recently decided to move to Dools 5 with Eclipse 3.4.2
(Ganymede).
We unfortunately hit a major 'show stopper' (for us). In the DSLR editor:
Context Assist + space + enter removes/replaces the whole line, not only the
place holder.
In other words:
DSL:
[*][]Log : {msg}=System.out.println("{msg}");
[*][]id1="some id label"
DSLR:
rule "MyRule"
when
then
end
If I Press L , control space --> the line Log:{msg} appears in the context
menu. Hit enter I get
Log :{msg}
Now, If want to replace msg by id1. I position the cursor in the {msg}, hit
ctrl space, id1 shows in the list. I hit enter the whole line disappear, and
I am left with
id1
instead of
Log : id1
Is this a setting somewhere in eclipse itself?? I doubt it.
The same thing use to work as expected in Drools 4.
thanks.
15 years, 3 months
