A java.util.Iterable is expected to provide iterators again and again. On Fri, Sep 14, 2018 at 10:53 PM Alejandro Alcalde <algu...@gmail.com> wrote:
> Hello all, > > I am trying to replicate the code in the Docs ( > https://ci.apache.org/projects/flink/flink-docs-release-1.6/dev/batch/dataset_transformations.html#combinable-groupreducefunctions > ) > > But I keep getting the following exception: > > The Iterable can be iterated over only once. Only the first call to > 'iterator()' will succeed. > > This is what I have: > > class MyCombinableGroupReducer > extends GroupReduceFunction[(Double, Double), Double] > with GroupCombineFunction[(Double, Double), (Double, Double)] { > import collection.JavaConverters._ > override def reduce( > in: java.lang.Iterable[(Double, Double)], > out: Collector[Double]): Unit = > { > val r = in.asScala.reduce ( (a, b) => ///ERROR HAPPENS HERE > (a._1, a._2 + b._2) > ) > out.collect(r._1 + r._2) > } > > override def combine( > in: lang.Iterable[(Double, Double)], > out: Collector[(Double, Double)]): Unit = { > ??? > } > } > > Where am I transversing `in` a second time? may be is the call to > `asScala`? > > Bests > > *-- Alejandro Alcalde - elbauldelprogramador.com > <http://elbauldelprogramador.com>* >
