I think a Tuple0 cannot be implemented like the current tuples, at least with respect to runtime serialization.
The system makes the assumption that it makes progress in consuming bytes when deserializing values. If a Tuple= never consumes data from the byte stream, this assumption is broken. It would need at least one marker byte. Then it effectively is a Tuple1<Byte> disgusing itself as a tuple0. On Sat, Aug 1, 2015 at 1:38 PM, Matthias J. Sax < mj...@informatik.hu-berlin.de> wrote: > I just double checked. Scala does not have type Tuple0. IMHO, it would > be best to remove Tuple0 for consistency. Having Tuple types is for > consistency reason with Scala in the first place, right? Please give > feedback. > > -Matthias > > > On 08/01/2015 01:04 PM, Matthias J. Sax wrote: > > I see. > > > > I think that it might be useful to have Tuple0, because in rare cases, > > you only want to "notify" a downstream operators (taking about > > streaming) that something happened but there is no actual data to be > > processed. Furthermore, if Flink cannot deal with Tuple0 it should be > > removed completely for consistency IMHO. > > > > I will open a JIRA for it. > > > > -Matthias > > > > On 07/31/2015 10:44 PM, Chesnay Schepler wrote: > >> also, I'm not sure if I ever sent a Tuple0 through a program, it could > >> be that the system freaks out. > >> > >> On 31.07.2015 22:40, Chesnay Schepler wrote: > >>> there's no specific reason. it was added fairly recently by me (mid of > >>> april), and you're most likely the second person to use it. > >>> > >>> i didn't integrate into all our tuple related stuff because, well, i > >>> never thought anyone would actually need it, so i saved myself the > >>> trouble. > >>> > >>>> Hi, > >>>> > >>>> is there any specific reason, why Tuple.getTupleClass(int arity) does > >>>> not support arity zero? There is a class Tuple0, but it cannot be > >>>> generator by Tuple.getTupleClass(...). Is it a missing feature (I > would > >>>> like to have it). > >>>> > >>>> -Matthias > >>>> > >>> > >>> > >> > > > >
