# All Classes

- All Classes Interface Summary Class Summary Enum Summary
  Class | Description
  --- | ---
  AssociationAggregationFunction | Specify aggregation logic used in `TaxonomyFacetIntAssociations` and `TaxonomyFacetFloatAssociations`.
  AssociationFacetField | Add an instance of this to your `Document` to add a facet label associated with an arbitrary byte[].
  BackCompatSortedNumericDocValues | Deprecated. Only here for back-compat support.
  CachedOrdinalsReader | Deprecated. Custom binary encodings for taxonomy ordinals are no longer supported starting with Lucene 9
  CachedOrdinalsReader.CachedOrds | Holds the cached ordinals in two parallel `int[]` arrays.
  ConcurrentSortedSetDocValuesFacetCounts | Like `SortedSetDocValuesFacetCounts`, but aggregates counts concurrently across segments.
  DefaultSortedSetDocValuesReaderState | Default implementation of `SortedSetDocValuesFacetCounts`.
  DimRange | Defines a single range in a `FacetSet` dimension.
  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
  DirectoryTaxonomyWriter.OrdinalMap | Mapping from old ordinal to new ordinals, used when merging indexes with separate taxonomies.
  DocValuesOrdinalsReader | Deprecated. Custom binary encodings for taxonomy ordinals are no longer supported starting with Lucene 9
  DoubleFacetSet | A `FacetSet` which encodes double dimension values.
  DoubleRange | Represents a range over double values.
  DoubleRange | Represents a double range for RangeOnRange faceting
  DoubleRangeFacetCounts | `Facets` implementation that computes counts for dynamic double ranges.
  DoubleRangeOnRangeFacetCounts | Represents counts for double range on range faceting.
  DrillDownQuery | A `Query` for drill-down over facet categories.
  DrillSideways | Computes drill down and sideways counts for the provided `DrillDownQuery`.
  DrillSideways.ConcurrentDrillSidewaysResult<R> | Result of a concurrent drill sideways search, including the `Facets` and `TopDocs`.
  DrillSideways.DrillSidewaysResult | Result of a drill sideways search, including the `Facets` and `TopDocs`.
  ExactFacetSetMatcher | A `FacetSetMatcher` which considers a set as a match only if all dimension values are equal to the given one.
  FacetCountsWithFilterQuery | Base class for facet counts.
  FacetField | Add an instance of this to your `Document` for every facet label.
  FacetLabel | Holds a sequence of string components, specifying the hierarchical name of a category.
  FacetQuery | A term `Query` over a `FacetField`.
  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 `LeafReaderContext`.
  FacetsCollectorManager | A `CollectorManager` implementation which produces FacetsCollector and produces a merged FacetsCollector.
  FacetsConfig | Records per-dimension configuration.
  FacetsConfig.DimConfig | Holds the configuration for one dimension
  FacetsConfig.DrillDownTermsIndexing | Drill down terms indexing option to control whether dimension and sub-path terms should be indexed.
  FacetSet | Holds a set of facet dimension values.
  FacetSetDecoder | A functional interface for decoding facet set values into comparable `long` ones.
  FacetSetMatcher | Matches the encoded `FacetSet` that was indexed in `FacetSetsField`.
  FacetSetsField | A `BinaryDocValuesField` which encodes a list of `facet sets`.
  FacetUtils | Utility class with a single method for getting a DocIdSetIterator that skips deleted docs
  FastTaxonomyFacetCounts | Computes facets counts, assuming the default encoding into DocValues was used.
  FloatAssociationFacetField | Add an instance of this to your `Document` to add a facet label associated with a float.
  FloatFacetSet | A `FacetSet` which encodes float dimension values.
  FloatTaxonomyFacets | Deprecated. Visibility of this class will be reduced to pkg-private in a future version.
  IntAssociationFacetField | Add an instance of this to your `Document` to add a facet label associated with an int.
  IntFacetSet | A `FacetSet` which encodes integer dimension values.
  IntTaxonomyFacets | Deprecated. Visibility of this class will be reduced to pkg-private in a future version.
  LabelAndValue | Single label and its value, usually contained in a `FacetResult`.
  LabelToOrdinal | Abstract class for storing Label->Ordinal mappings in a taxonomy.
  LongFacetSet | A `FacetSet` which encodes long dimension values.
  LongRange | Represents a range over long values.
  LongRange | Represents a long range for RangeOnRange faceting
  LongRangeFacetCounts | `Facets` implementation that computes counts for dynamic long ranges.
  LongRangeOnRangeFacetCounts | Represents counts for long range on range faceting.
  LongValueFacetCounts | `Facets` implementation that computes counts for all unique long values, more efficiently counting small values (0-1023) using an int array, and switching to a `HashMap` for values above 1023.
  LRUHashMap<K,​V> | LRUHashMap is an extension of Java's HashMap, which has a bounded size(); When it reaches that size, each time a new element is added, the least recently used (LRU) entry is removed.
  LruTaxonomyWriterCache | LRU `TaxonomyWriterCache` - good choice for huge taxonomies.
  LruTaxonomyWriterCache.LRUType | Determines cache type.
  MatchingFacetSetsCounts | Returns the counts for each given `FacetSet`
  MultiDoubleValues | Per-segment, per-document double values, which can be calculated at search-time.
  MultiDoubleValuesSource | Base class for producing `MultiDoubleValues`.
  MultiFacetQuery | A multi-terms `Query` over a `FacetField`.
  MultiFacets | Maps specified dims to provided Facets impls; else, uses the default Facets impl.
  MultiLongValues | Per-segment, per-document long values, which can be calculated at search-time.
  MultiLongValuesSource | Base class for producing `MultiLongValues`.
  NameHashIntCacheLRU | An LRU cache of mapping from name to int.
  OrdinalMappingLeafReader | A `FilterLeafReader` for updating facets ordinal references, based on an ordinal map.
  OrdinalsReader | Deprecated. Custom binary encodings for taxonomy ordinals are no longer supported starting with Lucene 9
  OrdinalsReader.OrdinalsSegmentReader | Returns ordinals for documents in one segment.
  ParallelTaxonomyArrays | Returns 3 arrays for traversing the taxonomy: `parents`: `parents[i]` denotes the parent of category ordinal `i`.
  ParallelTaxonomyArrays.IntArray | Abstraction that looks like an int[], but read-only.
  PrintTaxonomyStats | Prints how many ords are under each dimension.
  RandomSamplingFacetsCollector | Collects hits for subsequent faceting, using sampling if needed.
  Range | Base class for a single labeled range.
  Range | Base class for a single labeled range.
  RangeFacetSetMatcher | A `FacetSetMatcher` which considers a set as a match if all dimensions fall within the given corresponding range.
  ReindexingEnrichedDirectoryTaxonomyWriter | Use this `TaxonomyWriter` to append arbitrary fields to the ordinal documents in the taxonomy.
  SearcherTaxonomyManager | Manages near-real-time reopen of both an IndexSearcher and a TaxonomyReader.
  SearcherTaxonomyManager.SearcherAndTaxonomy | Holds a matched pair of `IndexSearcher` and `TaxonomyReader`
  SortedSetDocValuesFacetCounts | Compute facets counts from previously indexed `SortedSetDocValuesFacetField`, without require a separate taxonomy index.
  SortedSetDocValuesFacetField | Add an instance of this to your Document for every facet label to be indexed via SortedSetDocValues.
  SortedSetDocValuesReaderState | Wraps a `IndexReader` and resolves ords using existing `SortedSetDocValues` APIs without a separate taxonomy index.
  SortedSetDocValuesReaderState.DimTree | Holds children and sibling information for a single dimension.
  SortedSetDocValuesReaderState.OrdRange | Holds start/end range of ords, which maps to one dimension.
  StringDocValuesReaderState | Stores an `OrdinalMap` created for a specific `IndexReader` (`reader`) + `field`.
  StringValueFacetCounts | Compute facet counts from a previously indexed `SortedSetDocValues` or `SortedDocValues` field.
  TaxonomyFacetCounts | Deprecated. Custom binary encodings for taxonomy ordinals are no longer supported starting with Lucene 9.
  TaxonomyFacetFloatAssociations | Aggregates float values associated with facet fields.
  TaxonomyFacetIntAssociations | Aggregates int values previously indexed with `IntAssociationFacetField`, assuming the default encoding.
  TaxonomyFacetLabels | Utility class to easily retrieve previously indexed facet labels, allowing you to skip also adding stored fields for these values, reducing your index size.
  TaxonomyFacets | Deprecated. Visibility of this class will be reduced to pkg-private in a future version.
  TaxonomyFacetSumFloatAssociations | Deprecated. This class is being deprecated in favor of `TaxonomyFacetFloatAssociations`, which provides more flexible aggregation functionality beyond just "sum"
  TaxonomyFacetSumIntAssociations | Deprecated. This class is being deprecated in favor of `TaxonomyFacetIntAssociations`, which provides more flexible aggregation functionality beyond just "sum"
  TaxonomyFacetSumValueSource | Deprecated. This class is being deprecated in favor of `TaxonomyFacetFloatAssociations`, which provides more flexible aggregation functionality beyond just "sum"
  TaxonomyMergeUtils | Utility methods for merging index and taxonomy directories.
  TaxonomyReader | TaxonomyReader is the read-only interface with which the faceted-search library uses the taxonomy during search time.
  TaxonomyReader.ChildrenIterator | An iterator over a category's children.
  TaxonomyWriter | TaxonomyWriter is the interface which the faceted-search library uses to dynamically build the taxonomy at indexing time.
  TaxonomyWriterCache | TaxonomyWriterCache is a relatively simple interface for a cache of category->ordinal mappings, used in TaxonomyWriter implementations (such as `DirectoryTaxonomyWriter`).
  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.
  UTF8TaxonomyWriterCache | Deprecated. Use `LruTaxonomyWriterCache` instead.