question: private List < FacetResult > search ( ) throws IOException { DirectoryReader indexReader = DirectoryReader . open ( indexDir ) ; IndexSearcher searcher = new IndexSearcher ( indexReader ) ; SortedSetDocValuesReaderState state = new DefaultSortedSetDocValuesReaderState ( indexReader ) ; FacetsCollector fc = new FacetsCollector ( ) ; FacetsCollector . search ( searcher , new MatchAllDocsQuery ( ) , 10 , fc ) ; Facets facets = new SortedSetDocValuesFacetCounts ( state , fc ) ; List < FacetResult > results = new ArrayList < > ( ) ; results . add ( facets . getTopChildren ( 10 , "Author" ) ) ; results . add ( facets . getTopChildren ( 10 , "Publish Year" ) ) ; indexReader . close ( ) ; return results ; }
target:  User runs a query and counts facets. 