Hello everyone. I'm currently evaluating Drools as a part of my bachelor thesis. And I'm having trouble to categorize Drools regarding detection semantics of complex events.
I understand that there are two possibilities of timestamping events: just time points or time intervals (where a duration of 0 represents a time point event). Now, Drools definitely implements time intervals, no doubt there. Then I understand that there are semantic differences in detecting complex events. This problem stems from composition-operator based languages. If a complex event (represented by its pattern) is detected, it could get assigned the occurrence time as timestamp of the last event which was needed for the pattern OR it could get assigned an interval of the occurrence times of the first and the last event needed for the pattern. I have read a lot of papers which describe this problem. I have read the papers specified in the Fusion docs and even some more like 1. Walzer K, Groch M, Breddin T. Time to the Rescue - Supporting Temporal Reasoning in the Rete Algorithm for Complex Event Processing. 2008:635-642. and 1. Walzer K, Breddin T, Groch M. Relative temporal constraints in the Rete algorithm for complex event detection. Proceedings of the second international conference on Distributed event-based systems - DEBS ’08. 2008:147. Available at: http://portal.acm.org/citation.cfm?doid=1385989.1386008. But I can't seem to find a statement how Drools ultimately manages this. In Drools, there seems to be no such problem at all. Rules (LHS) can also feature facts which have no notion of time, and the user is able to set the timestamp (and duration) manually when inserting a new event through the RHS of a rule. Since its a rule based language, and the RETE algorithm works differently than the implementations of composition-operator based languages, I infer that there is no problem with detection semantics. Am I right here? Thanks in advance Kind regards Oliver -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Detection-semantics-tp2365940p2365940.html Sent from the Drools - Research mailing list archive at Nabble.com. _______________________________________________ drools-research mailing list [email protected] https://www.redhat.com/mailman/listinfo/drools-research
