Lucene 4.2.1 facet API

Provides faceted indexing and search capabilities (checkout the userguide).

See:
Description

Packages

org.apache.lucene.facet	faceted search
org.apache.lucene.facet.associations	Allows associating arbitrary values with a category.
org.apache.lucene.facet.codecs.facet42	Codec + DocValuesFormat that are optimized for facets.
org.apache.lucene.facet.collections	Various optimized Collections implementations.
org.apache.lucene.facet.complements	Allows to cache the total counts of categories, so that during search which returns a large number of results (>60% of segment size), the complement set of matching documents is counted.
org.apache.lucene.facet.encoding	Offers various encoders and decoders for category ordinals.
org.apache.lucene.facet.index	Facets indexing code.
org.apache.lucene.facet.params	Facets indexing and search parameters.
org.apache.lucene.facet.partitions	Category Partitions
org.apache.lucene.facet.sampling	Facets sampling.
org.apache.lucene.facet.search	Facets search code.
org.apache.lucene.facet.taxonomy	Taxonomy of Categories
org.apache.lucene.facet.taxonomy.directory	Taxonomy index implementation using on top of a Directory.
org.apache.lucene.facet.taxonomy.writercache	Improves indexing time by caching a map of CategoryPath to their Ordinal.
org.apache.lucene.facet.taxonomy.writercache.cl2o	Category->Ordinal caching implementation using an optimized data-structures
org.apache.lucene.facet.taxonomy.writercache.lru	An LRU cache implementation for the CategoryPath to Ordinal map
org.apache.lucene.facet.util	Various utilities for faceted search

Provides faceted indexing and search capabilities (checkout the userguide).