groupOrder = null;
}
}
OperatorDescriptorSingle props = useCombiner ?
(this.keys == null ? new AllGroupWithPartialPreGroupProperties() : new GroupReduceWithCombineProperties(this.keys, groupOrder)) :
(this.keys == null ? new AllGroupReduceProperties() : new GroupReduceProperties(this.keys, groupOrder));
return Collections.singletonList(props);
}