Package org.apache.lucene.facet

faceted search

This module provides multiple methods for computing facet counts and value aggregations:

• Taxonomy-based methods rely on a separate taxonomy index to map hierarchical facet paths to global int ordinals for fast counting at search time; these methods can compute counts ((FastTaxonomyFacetCounts, TaxonomyFacetCounts) aggregate long or double values TaxonomyFacetSumIntAssociations, TaxonomyFacetSumFloatAssociations, TaxonomyFacetSumValueSource. Add FacetField or AssociationFacetField to your documents at index time to use taxonomy-based methods.
• Sorted-set doc values method does not require a separate taxonomy index, and computes counts based on sorted set doc values fields (SortedSetDocValuesFacetCounts). Add SortedSetDocValuesFacetField to your documents at index time to use sorted set facet counts.
• Range faceting LongRangeFacetCounts, DoubleRangeFacetCounts compute counts for a dynamic numeric range from a provided ValueSource (previously indexed numeric field, or a dynamic expression such as distance).

At search time you first run your search, but pass a FacetsCollector to gather all hits (and optionally, scores for each hit). Then, instantiate whichever facet methods you'd like to use to compute aggregates. Finally, all methods implement a common Facets base API that you use to obtain specific facet counts.

The various FacetsCollector.search(org.apache.lucene.search.IndexSearcher, org.apache.lucene.search.Query, int, org.apache.lucene.search.Collector) utility methods are useful for doing an "ordinary" search (sorting by score, or by a specified Sort) but also collecting into a FacetsCollector for subsequent faceting.

Class Summary

Class	Description
DrillDownQuery	A Query for drill-down over facet categories.
DrillSideways	Computes drill down and sideways counts for the provided DrillDownQuery.
DrillSideways.DrillSidewaysResult	Result of a drill sideways search, including the Facets and TopDocs.
FacetField	Add an instance of this to your Document for every facet label.
FacetResult	Counts or aggregates for a single dimension.
Facets	Common base class for all facets implementations.
FacetsCollector	Collects hits for subsequent faceting.
FacetsCollector.MatchingDocs	Holds the documents that were matched in the AtomicReaderContext.
FacetsConfig	Records per-dimension configuration.
FacetsConfig.DimConfig	Holds the configuration for one dimension
LabelAndValue	Single label and its value, usually contained in a FacetResult.
MultiFacets	Maps specified dims to provided Facets impls; else, uses the default Facets impl.
TopOrdAndFloatQueue	Keeps highest results, first by largest float value, then tie break by smallest ord.
TopOrdAndFloatQueue.OrdAndValue	Holds a single entry.
TopOrdAndIntQueue	Keeps highest results, first by largest int value, then tie break by smallest ord.
TopOrdAndIntQueue.OrdAndValue	Holds a single entry.