method meaning of class Trigger

Posted by Soheil Pourbafrani on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/method-meaning-of-class-Trigger-tp21488.html

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?