Rich Window Function - When does close(tear down) method executes ?

[Swapnil Chougule]

I am using rich window function in my streaming project. I want "close"
method to get triggered after each window interval.
In my case, open gets executed life time once & close method doesn't get
executed ?

Can anybody help to sort out same ? I want tear down method after each
window interval.

Thanks,
Swapnil