Hmm, right, I didn't think about that. I'll add a warning. Thanks, Matthias
On Monday, 2012-11-12, Josh Wills wrote: > Not necessarily-- you can use a secondary sort to make a non-commutative > aggregator deterministic. But we should have a warning to that effect. > > J > > > On Mon, Nov 12, 2012 at 10:12 AM, Matthias Friedrich <[email protected]> wrote: > > > Hi, > > > > I would guess that Aggregator implementations have to be associative > > and commutative. Otherwise they can't be used in Combiners in a > > deterministic way. Am I right? > > > > If this is the case I'd suggest we add a big fat warning to our > > StringConcatAggregator, because string concatenation isn't > > commutative. Or maybe even remove it from our core API because it's a > > bad role model? > > > > Thanks, > > Matthias > >
