[rules-users] On demand events

Hello, I'm a new user of Drools and have experimented with the basics. I am interested in processing events and have had success when defining rules of the type: rule "example" when Event1(..) from entry-point Event1Store Event2(..) from entry-point Event2Store then System.out.println("Fired!"); end Where events of type Event1 and Event2 are continually injected into entry-points within the working memory. The events I have in mind are formed from data that sit in data stores that are expensive to access and I would like to explore strategies for minimising access to these. In the above example, I assume that if Drools does not match the pattern Event1(..) then it will not try and match the pattern Event2(..), in which case it would not be necessary to construct facts/events which may match the Event2(..) pattern. I understand that the 'from' statement can be used to evaluate facts that are not in working memory, on this basis I have defined proxy objects that are inserted into working memory which are then evaluated for the actual data from the database on demand: 1 rule "example" 2 when 3 $event1Provider : Event1Provider() 4 Event1(..) from $event1Provider.evaluate() 5 $event2Provider : Event2Provider() 6 Event2(..) from $event2Provider.evaluate() 7 then 8 System.out.println("Fired!"); 9 end On the basis that if line 4 fails to match, then line 5 and 6 will not get evaluated therefore avoiding accessing the database describing the Event2 fact/event. I think that this works - but only once, since it looks like the system is treating these as facts, that don't expire, rather than events. Is it the case that the 'from' statement cannot be used for events in this way? If not, what approach should be taken to addressing the problem I am trying to solve? Any direction would be much appreciated. James