Interface Summary
Interface	Description
CategoryListBuilder	Builds a category list data by encoding the appropriate information for every category and ordinal given to `CategoryListBuilder.build(IntsRef, Iterable)`.

Class Summary
Class	Description
CountingListBuilder	A `CategoryListBuilder` which builds a counting list data by encoding the category ordinals into one or more `BytesRef`.
DrillDownStream	A `TokenStream` which creates category drill-down terms.
FacetFields	A utility class for adding facet fields to a document.
OrdinalMappingAtomicReader	A `FilterAtomicReader` for updating facets ordinal references, based on an ordinal map.

Package org.apache.lucene.facet.index Description

Indexing of document categories

Attachment of CategoryPath's or CategoryAssociation's to a given document using a Taxonomy.