[rules-users] Retrieving timestamps from default Drools Fusion event

Hi, First time posting in the mailing list, so I apologise if I make any silly mistakes. I have two classes MachineOnline and MachineOffline, which denote when a machine is online and offline respectively public class MachineOnline { int machineId } These are declared in the drl file as events, so Drools Fusion automatically generates the timestamp for me (I am running in STREAM mode, so i get real time updates on the machine status) declare MachineOnline @role(event) end I then have a rule to generate the duration when the machine is online, but I cannot seem to extract the timestamp that drools automatically inserts. A thread a few years ago suggested using .startTimestamp, but Drools does not seem to recognise it as a field. I believe that needs an EventFactHandle, but I'm not sure how to retrieve that inside the drl file. rule "Find duration machine is online" when $message1 : MachineOnline() $message2: MachineOffline(machineId == $message1.machineId && this after $message1) // + more rules to handle edge cases then //processing duration = $message2.startTimestamp - $message1.startTimestamp ? end The eventual aim is to allow for a query that allows me to find how long the machine is online for during a specified time interval, so if there is a way to do this without needing to retrieve the actual timestamp of each event, that will be great too. Or would it be better to manually define a timeStamp field for each event? I've been using the default one as that together with the pseudo allows for easy unit testing. Thanks a lot! Regards Jing