Lucene.Net.Facet.FacetsCollector.DoSearch C# (CSharp) Method

        private static TopDocs DoSearch(IndexSearcher searcher, ScoreDoc after, Query q, Filter filter, int n, Sort sort, bool doDocScores, bool doMaxScore, Collector fc)
        {

            if (filter != null)
            {
                q = new FilteredQuery(q, filter);
            }

            int limit = searcher.IndexReader.MaxDoc;
            if (limit == 0)
            {
                limit = 1;
            }
            n = Math.Min(n, limit);

            if (after != null && after.Doc >= limit)
            {
                throw new System.ArgumentException("after.doc exceeds the number of documents in the reader: after.doc=" + after.Doc + " limit=" + limit);
            }


            if (sort != null)
            {
                if (after != null && !(after is FieldDoc))
                {
                    // TODO: if we fix type safety of TopFieldDocs we can
                    // remove this
                    throw new System.ArgumentException("after must be a FieldDoc; got " + after);
                }
                const bool fillFields = true;
                var hitsCollector = TopFieldCollector.Create(sort, n, (FieldDoc)after, fillFields, doDocScores, doMaxScore, false);
                searcher.Search(q, MultiCollector.Wrap(hitsCollector, fc));
                return hitsCollector.TopDocs();
            }
            else
            {
                // TODO: can we pass the right boolean for
                // in-order instead of hardwired to false...?  we'd
                // need access to the protected IS.search methods
                // taking Weight... could use reflection...
                var hitsCollector = TopScoreDocCollector.Create(n, after, false);
                searcher.Search(q, MultiCollector.Wrap(hitsCollector, fc));
                return hitsCollector.TopDocs();
            }
        }
    }