<br> Hi Tina,<br><br> 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.<br>
<br> I recommend you read the Drools Expert documentation as well, as Fusion features are additions to the overall Expert features and syntax. <br><br> 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.<br>
<br> 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:<br>
<br>$ea : EventA()<br>$eb : EventB( this after[10s,30s] $ea )<br><br> 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.<br>
<br> Hope it helps,<br><br> Edson<br><br><div class="gmail_quote">2010/5/7 Tina Vießmann <span dir="ltr"><<a href="mailto:tviessmann@stud.hs-bremen.de">tviessmann@stud.hs-bremen.de</a>></span><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
Hello everybody :)<br>
<br>
I'm completely new to the Drools universe. I've discovered Drools, or more<br>
specifically Drools Fusion, by looking for a powerful CEP engine.<br>
<div class="im">I've read the DF user guide and came up with some issues about DF features.<br>
It would be great, if anyone can give me some explanations and/or refer to<br>
different information sources.<br>
<br>
My questions:<br>
<br>
1. Persistence of events:<br>
</div>I know that DF can store events explicitly and implicitly. But does it<br>
store events in persistent (e.g., I can continue my computation after a<br>
reboot)? If it does, how are the events stored?<br>
<br>
2. Sliding windows:<br>
<div class="im">It's written that a window contains the last X events/the event occurred<br>
</div>in the last X time units. Is it somehow possible to specify a window for<br>
process only old events - which does not catch up to the latest event?<br>
(Lets assume we have the times A, B and C with: A < B < C and C ==<br>
current time. Is it possible to specify a window that process events<br>
occurred between A and B?)<br>
So are more complex windows like described in chapter 7 of the book 'Event<br>
Processing in Action' (see <a href="http://www.manning.com/etzion/" target="_blank">http://www.manning.com/etzion/</a>) possible?<br>
<br>
<br>
Are there any (step-to-step) tutorials / how-tos about simple DF programs?<br>
<br>
<br>
In case my questions are stupid because they can be answered when knowing<br>
Drools, but I've got absolute now experience using Drools. At the moment I<br>
kind of have the feeling, Drools is a little bit too complex for just<br>
using to implement CEP applications...<br>
<br>
<br>
Thanks for any help! :)<br>
<font color="#888888"><br>
Tina<br>
</font><div><div></div><div class="h5"><br>
<br>
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</div></div></blockquote></div><br><br clear="all"><br>-- <br> Edson Tirelli<br> JBoss Drools Core Development<br> JBoss by Red Hat @ <a href="http://www.jboss.com">www.jboss.com</a><br>