[rules-users] Re: Load working memory with "old/existsing" facts

[Mark Proctor]

I've found the issue, its removing the item twice. I'll fix this for the 
point release next week.
http://jira.jboss.org/jira/browse/JBRULES-1033

Thanks

Mark
Mark Proctor wrote:
> hmm that looks like a bug, I'll look into it. We do have 
> unit/integration tests for this, so I'd be interested to know what you 
> are doing to kick this off. Are you just adding a clear agenda after 
> the fireAllRules() in that example?
>
> Mark
> tom at bergstein-soraic.de wrote:
>>
>> Thank you for the hint. I've tried to use clearAgenda() but I've 
>> following error:
>>
>>  
>>
>> Exception in thread "main" _java.lang.NullPointerException_
>>
>> at org.drools.util.LinkedList.remove(_LinkedList.java:97_)
>>
>> at 
>> org.drools.common.DefaultAgenda.removeScheduleItem(_DefaultAgenda.java:150_) 
>>
>>
>> at 
>> org.drools.common.ScheduledAgendaItem.remove(_ScheduledAgendaItem.java:159_) 
>>
>>
>> at org.drools.common.DefaultAgenda.clearAgenda(_DefaultAgenda.java:362_)
>>
>> at 
>> org.drools.common.AbstractWorkingMemory.clearAgenda(_AbstractWorkingMemory.java:363_) 
>>
>>
>> at 
>> org.drools.examples.TroubleTicketExample.main(_TroubleTicketExample.java:58_)
>>
>>
>>   
>>
>> Is there anything special to consider when using clearAgenda()?
>>
>>  
>>
>>  
>>
>>  
>>
>> ----- Edison wrote:  
>>
>>  Technically it is possible and supported to serialize working 
>> memories. Although, we did faced problems with large serializations 
>> due to a known recursion issue in JDK. There is a JIRA for that, but 
>> I don't have the link right now.
>>
>>     Now, if you want to reassert objects without firing rules, maybe 
>> what you can do is call WorkingMemory.clearAgenda() after reasserting 
>> the ob! jects. Not sure if that will give you the results you expect.
>>
>>     []s
>>     Edson
>>
>> 2007/7/25, Arjun Dhar <dhar_ar at yahoo.com <mailto:dhar_ar at yahoo.com>>:
>>
>>     bergstein-soraic.de
>>     </xml/deref?link=http%3A%2F%2Fbergstein-soraic.de>> writes:
>>
>>     >
>>     >
>>     > I've a use case that is similar to the TroubleTicketExample that
>>     is part of
>>     the drools examples.
>>     > In this examples new tickets are inserted via
>>     workingMemory.assertObject
>>     (ticket). However, tickets are usually managed and stored in a
>>     ticketing system
>>     (Remedy, Peregrine, etc). When I stop the drools engine, I assume
>>     that the
>>     state of the working memory is lost. When I start the engine
>>     again, I'd like to
>>     load the working memory with the tickets that are stored in the
>>     tic! keting
>>     system, but I don't want to fire all rules, since I'd to avoid
>>     that rules are
>>     executed again (e.g., rule "Escalate" -> send a e-mail), which
>>     have been
>>     already executed before the drools engine has
>>     >   been stopped. Existing tickets in the ticketing system are
>>     important facts
>>     for the rules!
>>     >   and therefore the need to be loaded into the morking memory.
>>     >
>>     >
>>     > Is there a way to build up the working memory with initial facts?
>>     > Can I persist the state of the working memory and load it later
>>     again?
>>     >
>>     >
>>     > Many thanks in advance,
>>     > Tom
>>     >
>>
>>     Hey my two bits,
>>
>>     Assuming I dont know much about StatefulSessions holding objects
>>     I wanted to
>>     check with you, is this safe? I'm not sure over a period of time
>>     if your
>>     objects would be released with a StatefulSession/WorkingMemory,
>>     would recommend
>>     you 'soak test' (test over a period of time with consistent l oad)
>>
>>     But here is the possibility:
>>     Well the interface WorkinfgMemory -- extends --> Eventmanager
>>     which extends
>>     Serializable.
>>
>>     You could try serializing the object, or query your WorkingMemory
>>     for its state
>>     and save it to a database. Am assuming you are using
>>     StatefulSession so you
>>     will have access to WorkingMemory.
>>
>>     Conceptually I just think its worng to use a Rule Engine to
>>     persist state over
>>     a such a long period of time. Any expert opinion?
>>
>>     regards,
>>     Arjun
>>
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>>
>>
>>
>>
>> -- 
>>   Edson Tirelli
>>   Soft! ware Engineer - JBoss Rules Core Developer
>>   Office: +55 11 3529-6000
>>   Mobile: +55 11 9287-5646
>>   JBoss, a division of Red Hat @ www.jboss.com 
>> </xml/deref?link=http%3A%2F%2Fwww.jboss.com>
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