# Package org.apache.lucene.facet.taxonomy.directory

Taxonomy index implementation using on top of a Directory.

See: Description

Interface Summary
DirectoryTaxonomyWriter.OrdinalMap: Mapping from old ordinal to new ordinals, used when merging indexes with separate taxonomies.

Class Summary
DirectoryTaxonomyReader: A `TaxonomyReader` which retrieves stored taxonomy information from a `Directory`.
DirectoryTaxonomyWriter: `TaxonomyWriter` which uses a `Directory` to store the taxonomy information on disk, and keeps an additional in-memory cache of some or all categories.
DirectoryTaxonomyWriter.DiskOrdinalMap: `DirectoryTaxonomyWriter.OrdinalMap` maintained on file system
DirectoryTaxonomyWriter.MemoryOrdinalMap: `DirectoryTaxonomyWriter.OrdinalMap` maintained in memory

## Package org.apache.lucene.facet.taxonomy.directory Description

Taxonomy index implementation using on top of a Directory.