[rules-users] Need advice on asynchronicity

I'm really pretty new to Drools, so bear with me here: I'm trying to develop some rules for classifying domains as belonging to spammers or not, based on various test scenarios. Whether to even start these test scenarios is also controlled by various rules, like occurrences within a timeframe, so a rule engine seems a natural fit. So how I might write some rules, off the top of my head: rule "Lookup A Records" when d : Domain( name : n, arecs == null ) not Verdict(domain == d) then # lookup_a_records is potentially quite slow modify( d ) { arecs = lookup_a_records(n) } end rule "Spammy host" when # isAnyBlacklisted just looks up each record in a DNS zone, very quick d : Domain( eval( isAnyBlacklisted( d.arecs ) ) not Verdict(domain == d) then insert( new Verdict(d, SPAM) ) end First off, I wouldn't mind being able to refactor those "not Verdict(domain == d)" conditions out somehow ... agenda groups, perhaps? My main problem however is: I want lookup_a_records() to be asynchronous. It's potentially very slow, and I have hundreds of other domains to check (I have other scenarios that are slower than mere DNS lookups, this is just an example). Just to add to the fun, there can only be so many queries outstanding at any one time, so I'm looking at using a queue somewhere. I'm thinking I could lose the modify in the first rule, and make lookup_a_records schedule some asynchronous call through a ThreadPoolExecutor that modifies the fact -- hopefully directly, but is a session threadsafe? Are there any examples I can look at where the RHS modifies and inserts facts asynchronously? Chuck