Hi Soheil, Flink support many kinds of time window. The "onXXXTime" interface method would be triggered based on the time characteristic you chose, you should read the documentation that Chesnay provided and this documentation : https://ci.apache.org/projects/flink/flink-docs-master/dev/event_time.html#event-time--processing-time--ingestion-time
Thanks, Vino 2018-07-16 20:49 GMT+08:00 Chesnay Schepler <ches...@apache.org>: > Did you read the documentation? https://ci.apache.org/projects > /flink/flink-docs-master/dev/stream/operators/windows.html#triggers > > > On 16.07.2018 14:45, Soheil Pourbafrani wrote: > >> Hi, >> >> In extending class Trigger we have methods like onElement, >> onProcessingTime and onEventTime. I know the method onElement will be >> called when a element is added to the window, but I have no idea about when >> two other methods onProcessingTime and onEventTime will be called? >> > > >