Re: [drools-user] Rule Execution Flow

No, the entire rule set does not get re-evaluated if the WorkingMemory changes.  When a new fact is asserted, that fact gets "matched" against the rule set, but *only* that fact.  Previous matches don't happen again, otherwise you'd constantly be getting recursion problems.  Drools isn't that inefficient -- it can't afford to be!

Take a look at the example code and DRL files distributed with Drools.  Those examples should show you how various very simple problems are solved, and reveal more of how rules interact with each other.  Also, you should definitely dive right into trying out some code and rules of your own, that will help you iteratively build up your rules set.  I think you'll find it's simpler than you think.  More complex rules do require complex logic, but it is quite possible to start simple.

Also, read the manual and become familiar with the RETE algorithm and other algorithms Drools uses -- they're only lightly explained in the manual, but there are plenty of other engines based on Rete and other info sources (like the Wikipedia page on RETE:  
http://en.wikipedia.org/wiki/Rete_algorithm).  That will better explain how rule matching happens.

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Michael J. Suzio
msuzio@xxxxxxxxx