Hi,
This was the exact need that motivated me to rework the windowing and
introduce the StreamWindow abstraction which can hold any metadata that
represents the current window.
At this moment it only contains a unique id but this could be extended
easily.
When the user created a windoweddatastream by applying some windowed
tranformation he can call .getDiscretizedStream() which will return a
stream of StreamWindows from which the user can extract any metadata
afterwards.
So this is practically something we can add already easily and no need to
rewrite any logic.
Cheers,
Gyula
On Tuesday, May 12, 2015, Aljoscha Krettek <aljos...@apache.org> wrote:
> Hi,
> I'll try to make it quick this time. I think we need to make
> information about the event time of an element and information about
> windows in which it resides accessible to the user. A simple example
> would be the aggregation of some user behaviour, for example:
>
> in = clickSource()
>
> analysedData = in
> .window(10 minutes).every(5 minutes)
> .groupBy("userId")
> .filter(is something interesting)
> .sum("something")
>
> analysedData.storeToMySystem()
>
> Now the results of this window aggregation tell me that at some point,
> there was some window and in this window some attribute summed up to
> this. This might not be very helpful. What might be helpful is the
> information that there occurred a spike in something at 12:45 on
> Wednesday. Therefore, I think we need to make this information
> available somehow.
>
> I only have some rough Ideas about how this might work, but I would
> first like to discuss whether others even think this necessary. So
> fire away...
>
> Cheers,
> Aljoscha
>
