[rules-users] Getting started with Drools Fusion

[Tina Vießmann]

Thank you, Edsons. You've answered my questions saitsfying. :)

I will read the Drools Expert UG - I've added it to my ToDo-list some days
ago. Lets see how DF+DE will in the end beat IEP and Esper. :)

Tina


>    Hi Tina,
>
>    I might look daunting at first, but I hope once you start using it, you
> will realize how powerful the concept of enabling CEP for rules and
> processes is and how simple that becomes in Drools as compared to
> integrating heterogeneous products for the same task.
>
>    I recommend you read the Drools Expert documentation as well, as Fusion
> features are additions to the overall Expert features and syntax.
>
>    Regarding your questions: drools does not handles persistence by
> itself.
> It delegates to the application to decide what to do with them. You can of
> course persist individual events in a database or disk, or you can persist
> drools session snapshots if that fits better your application model.
>
>    Sliding windows are always based on the current time or latest event,
> but
> Drools offers the complete set of 13 temporal operators and their
> negations.
> So you can reason over times A and B. For instance, you want to check that
> event Eb happened between 10s and 30s after Ea. You can write that as:
>
> $ea : EventA()
> $eb : EventB( this after[10s,30s] $ea )
>
>    So that creates a arbitrary "windows of interest" that are not based on
> the current time, but otherwise anchored on each EventA that is received
> by
> the engine.
>
>    Hope it helps,
>
>    Edson
>
> 2010/5/7 Tina Vießmann <tviessmann at stud.hs-bremen.de>
>
>> Hello everybody :)
>>
>> I'm completely new to the Drools universe. I've discovered Drools, or
>> more
>> specifically Drools Fusion, by looking for a powerful CEP engine.
>> I've read the DF user guide and came up with some issues about DF
>> features.
>> It would be great, if anyone can give me some explanations and/or refer
>> to
>> different information sources.
>>
>> My questions:
>>
>> 1. Persistence of events:
>> I know that DF can store events explicitly and implicitly. But does it
>> store events in persistent (e.g., I can continue my computation after a
>> reboot)? If it does, how are the events stored?
>>
>> 2. Sliding windows:
>> It's written that a window contains the last X events/the event occurred
>> in the last X time units. Is it somehow possible to specify a window for
>> process only old events - which does not catch up to the latest event?
>> (Lets assume we have the times A, B and C with: A < B < C  and  C ==
>> current time. Is it possible to specify a window that process events
>> occurred between A and B?)
>> So are more complex windows like described in chapter 7 of the book
>> 'Event
>> Processing in Action' (see http://www.manning.com/etzion/) possible?
>>
>>
>> Are there any (step-to-step) tutorials / how-tos about simple DF
>> programs?
>>
>>
>> In case my questions are stupid because they can be answered when
>> knowing
>> Drools, but I've got absolute now experience using Drools. At the moment
>> I
>> kind of have the feeling, Drools is a little bit too complex for just
>> using to implement CEP applications...
>>
>>
>> Thanks for any help! :)
>>
>> Tina
>>
>>
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>> rules-users at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/rules-users
>>
>
>
>
> --
>  Edson Tirelli
>  JBoss Drools Core Development
>  JBoss by Red Hat @ www.jboss.com
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