ExternalTimeBatch window to support round

[RalphSu]

Currently external time batch is trigger by events driven, which is correct and expected. But there is no time round.

Is that possible to support feature like
from stream#window.externalTimeBatch(timestamp, 5 min, 1 second), here the optional third parameter is to specify the round. That's if given 1 seconds, each time window should be starting seconds. (Instead, currently we might start by event timestamp which is not necessary to be round as starting seconds)

[mohanvive]

@RalphSu , above feature is already implemented and available in the master branch.. See [1], I believe, this is what you are looking for..

[1] https://docs.wso2.com/display/CEP420/Inbuilt+Windows#InbuiltWindows-externalTimeBatchexternalTimeBatch

[RalphSu]

@mohanvive i did check the PR of #170, but it looks something different. I'm try to generate something like

timewindow point | avg(value) | count(value)
2016-8-4 10:25:01 000 | 50 | 10
2016-8-4 10:25:02 000 | 30 | 20
...

That's mean i would to have time batch in round time point. while current external timebatch implementation might have this timewindow point not align to round point (say it could be possible a batch window starting from 2016-8-4 10:25:01 010 )

[mohanvive]

Hmm, If you put start time as 0 then it will give the output in round time point (in GMT)

[RalphSu]

Rechecked, looks good. Will evaluate with test again. Closing this one. Thanks, @mohanvive