[rules-users] Query in stateless knowledge session returns no results
Mark Proctor
mproctor at codehaus.org
Sun Jul 31 12:45:59 EDT 2011
On 31/07/2011 17:25, Heijink, Hank wrote:
> Aha! I missed the line about the dispose. That makes a lot of sense.
> What I don't understand is why the example 3.37 in the docs would
> work. If I understand what you're saying, it shouldn't.
It should work, as long as the query is executed as part of the same
execute batch. We have unit tests f or that too somewhere.
mark
>
> Thanks!
> Hank
>
> Sent from my iPhone
>
> On Jul 30, 2011, at 8:27 AM, "Wolfgang Laun" <wolfgang.laun at gmail.com
> <mailto:wolfgang.laun at gmail.com>> wrote:
>
>> StatelessKnowledgeSession.execute(...) executes the command(s) and
>> /finally calls dispose()/ on the session. Use a stateful session or a
>> global (filled with a low-salience rule) or - simply use the
>> getObjects command.
>> -W
>>
>> On 29 July 2011 22:47, Heijink, Hank <heijink at audible.com
>> <mailto:heijink at audible.com>> wrote:
>>
>> Hi all,
>>
>> I'm new to Drools, so please excuse me if I'm asking about the
>> obvious--it's certainly not obvious to me. The problem is this: I
>> use a stateless knowledge session where a list of facts is
>> inserted. The rules that fire create new facts, and after all the
>> rules have fired, I'd like to obtain a list of all the facts (the
>> old and the new). The best way seemed to use a query. I'm using
>> Drools 5.1 on Linux.
>> This is part of my .drl file (without the imports):
>>
>> rule "create badge"
>> when
>> Event ( eventType == EventType.SOME_EVENT_TYPE )
>> not BadgeState ( identifier == "badge" )
>> then
>> insert( new BadgeState("badge") );
>> end
>>
>> query "all badges"
>> aBadge : BadgeState()
>> end
>>
>> This is the Java code:
>>
>> StatelessKnowledgeSession ksession =
>> StatsKnowledgeBase.getKnowledgeBase().newStatelessKnowledgeSession();
>>
>> // Create a list of share events
>> ArrayList<Event> events = new ArrayList<Event>();
>> Date now = new Date();
>> MobileDevice aDevice = new
>> MobileDevice("uniqueId", "deviceType");
>> for (int i = 0; i < 5; i++) {
>> Event anEvent = new Event.Builder(now,
>> aDevice, "aCustomer", EventType.SOME_EVENT_TYPE).build();
>> events.add(anEvent);
>> }
>>
>> // Create the query for the badges
>> List<Command> commands = new ArrayList<Command>();
>>
>> commands.add(CommandFactory.newInsertElements(events));
>> commands.add(CommandFactory.newQuery("all badges",
>> "all badges"));
>>
>> // Feed the events into Drools
>> KnowledgeRuntimeLogger logger =
>> KnowledgeRuntimeLoggerFactory.newConsoleLogger(ksession);
>> ExecutionResults results = ksession.execute(
>> CommandFactory.newBatchExecution(commands) );
>> NativeQueryResults queryResults =
>> (NativeQueryResults)results.getValue("all badges");
>>
>> // At this point, queryResults is empty.
>>
>> logger.close();
>>
>> // Get a list of badges
>> List<BadgeState> badges = new ArrayList<BadgeState>();
>> for (Iterator<QueryResultsRow> i =
>> queryResults.iterator(); i.hasNext(); ) {
>> QueryResultsRow result = i.next();
>> BadgeState obj =
>> (BadgeState)result.get("aBadge");
>> badges.add(obj);
>> }
>>
>> The logger shows me that the BadgeState object is created, but
>> the query returns an empty list. I've searched the documentation,
>> which suggests that I'm doing it right
>> (http://drools.herod.net/drools-expert/html/ch03.html#d0e1956,
>> example 3.37), the archives of this mailinglist, and the web, so
>> far without success.
>>
>> Clearly, I'm missing something, and I have the nagging feeling
>> that it's something simple...
>>
>> Any help is much appreciated!
>>
>> Best,
>> Hank
>>
>>
>> _______________________________________________
>> rules-users mailing list
>> rules-users at lists.jboss.org <mailto:rules-users at lists.jboss.org>
>> https://lists.jboss.org/mailman/listinfo/rules-users
>>
>>
>> _______________________________________________
>> rules-users mailing list
>> rules-users at lists.jboss.org <mailto:rules-users at lists.jboss.org>
>> https://lists.jboss.org/mailman/listinfo/rules-users
>
>
> _______________________________________________
> rules-users mailing list
> rules-users at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/rules-users/attachments/20110731/380aa26a/attachment.html
More information about the rules-users
mailing list