[FLINK-3536] Make clearer distinction between event time and processing time

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 1.0.0
• Component/s: API / DataStream
• Assignee: Aljoscha Krettek
• Reporter: Till Rohrmann
• Created: 29/Feb/16 13:42
• Updated: 29/Feb/16 19:53
• Resolved: 29/Feb/16 19:53

Description

If you define your own windows it is easy to mix up the time characteristic with the wrong set of predefined WindowAssigners. You cannot use processing time with a TumblingTimeWindows window assigner, for example.

Neither from the name of TumblingTimeWindows nor from the JavaDocs it is clearly obvious that this WindowAssigner can only be used with event time. I think it would be better to rename the event time window assigner to something like TumblingEventTimeWindows. Additionally, we could extend the JavaDocs a bit, since not everyone knows that "based on the timestamps" means based on event time.