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 _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

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(a)stud.hs-bremen.de&gt; > >> 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 >> >> >> _______________________________________________ >> rules-users mailing list >> rules-users(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/rules-users >> > > > > -- > Edson Tirelli > JBoss Drools Core Development > JBoss by Red Hat @ www.jboss.com > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users