[rules-users] Inserting a fact via a specific entry point inside a rule
Justin King
justin.matthew.king at gmail.com
Sun Aug 16 21:31:33 EDT 2009
Hi Everyone,
I'm aware that in Drools you can use 'insert()' in the 'then' part of a rule
to insert a new fact into the memory, meaning more rules may be fired based
on the addition of this new fact. I wish to do a similar thing, but I wish
to insert the fact into a specific entry point. My current rule code to do
this is:
rule "Allow message buyBook"
no-loop true
when
$event : MessageRecievedEvent(operationName == "buyBook") from
entry-point "t1 stream"
then
MessageRecievedEvent mre = new MessageRecievedEvent();
mre.setOperationName("sellBook");
StatefulKnowledgeSession session =
kcontext.getKnowledgeRuntime().getKnowledgeBase().newStatefulKnowledgeSession();
WorkingMemoryEntryPoint obStream =
session.getWorkingMemoryEntryPoint("ob1 stream");
obStream.insert(mre);
session.fireAllRules();
end
rule "ob1"
no-loop true
when
$event : MessageRecievedEvent(operationName == "sellBook") from
entry-point "ob1 stream"
then
System.out.println("executed");
end
Which is pretty hideous, but it does work, causing the second rule to fire
after the first one. What I would like is something like:
rule "Allow message buyBook"
no-loop true
when
$event : MessageRecievedEvent(operationName == "buyBook") from
entry-point "t1 stream"
then
MessageRecievedEvent mre = new MessageRecievedEvent();
mre.setOperationName("sellBook");
insert(mre, "ob1 stream")
end
rule "ob1"
no-loop true
when
$event : MessageRecievedEvent(operationName == "sellBook") from
entry-point "ob1 stream"
then
System.out.println("executed");
end
Is something like this possible or will I have to write a function to do it?
I'm also a bit concerned about the performance hit of creating a whole new
StatefulKnowledgeSession to fire the second rule, I'd like to just use the
current one.
Thanks,
Justin
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/rules-users/attachments/20090817/6d15c27d/attachment.html
More information about the rules-users
mailing list