facet filtering

[Daniel Rosher]

Hi,

How can I have faceting on a subset of the query docset e.g. with something
akin to:

SimpleFacets.base =
SolrIndexSearcher.getDocSet(
Query mainQuery,
SolrIndexSearcher.getDocSet(Query filter)
)

Is there anything like facet.fq?

Cheers,
Dan