This email has at least 3 mistakes, please ignore it. I need to rethink it.

2018-04-25 18:45 GMT+02:00 Pawel Szczur <[email protected]>:

> Hi,
>
> I'm using Beam since Google Dataflow has been made public.
> There used to be MapFn. Some time later it was removed.
>
> Now we have MapElements helper which kind of is suppose to do similar
> things.
> Using it with new Java 8 API seems pretty ugly to me, especially when I
> have something like:
>
> PCollection<KV<Class1, Class2>> input = ...;
> input.apply(
>   MapElements.into(*?*).via(v -> KV.of(newKey(v.getKey()), v.getValue()));
>
> I would need to replace *?* by KVCoder.of(KeyCoder.of(), ValueCoder.of()).
> This is troublesome especially when in a longer transformation chains.
>
> For me, it's became easier to write:
> input.apply(DoFn(new ReplaceKey()))
> where ReplaceKey is a implementation of SimpleFunction defined somewhere
> and just replacing KV's key.
>
> I'm wondering, am I missing something?
>
> Cheers, Paweł Szczur
>
>
>
>

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