Facet support sorting through FacetRequest.SortOrder. This is used in the ResultSortUtils. For my application it would be very nice if the facets can also be sorted on their label.
I think this could be accomplished by altering FacetRequest with an extra enum SortType, and two extra Heap in ResultSortUtils which instead of comparing the double value, compare the CategoryPath.
What do you think of this idea? Or could the same behaviour be accomplished in a different way already?
(btw: I tried building this patch on the trunk of lucene5.0; but I couldn't get the maven build to build correctly. I will try again lateron on the 4.6 branch.