If there is no other attribute that distinguishes between the two Foo objects at the same time and with the same status, then the theory says that there is just one fact/event and you just happen to have the data duplicated. Getting rid of the duplicate may be one way of solving your problem. Another approach would be to create a marker fact saying that you've dealt with a Foo at a certain time, and check for its absence, both in the rule you've (almost) shown. -W On 16/04/2013, burmanator <alexburman(a)gmail.com&gt; wrote: > I am trying to track when an event object Foo with a distinguishing > identifier of Status. > I want to try and identify a list of events when a Foo event with Status 2 > happens after an event with Status 1 but at the same time a Status 1 has > not > happened before. > > fight now I've come up with: > > $foo1 : Foo($status : Status) > > not(Foo(Status == $status. this before $foo1)) > > $foos : ArrayList (size>0) from collect ( Foo(Status != $status, this after > $foo1)) > > Part of the problem I am having, is that a Foo event with the same Status > can happen at the same timestamp. How do I get it to work so the rule only > triggers once for multiple events on the same timestamp? > > > > -- > View this message in context: > http://drools.46999.n3.nabble.com/Drools-Fusion-Finding-an-event-that-occ... > Sent from the Drools: User forum mailing list archive at Nabble.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