[rules-users] Fusion: Null pointer exception when using sliding windows

I am getting a null pointer exception when I try and use a sliding window. The rule I'm trying to run is: $primary : Foo($name : Name) over window length(24) $prev : ArrayList(size<1) from collect ( Foo(Name == $name, this before $primary)) I am trying to look at the last 24 Foo events and have the rule only trigger when an event with that name hasn't been seen before. I also get a null pointer when I try and do a time window and no Foo events happen within the window. Shouldn't the rule just not fire? -- View this message in context: http://drools.46999.n3.nabble.com/Fusion-Null-pointer-exception-when-usin... Sent from the Drools: User forum mailing list archive at Nabble.com.