# Uses of Package
org.apache.lucene.index

Packages that use org.apache.lucene.index
Package
Description
org.apache.lucene.codecs
Codecs API: API for customization of the encoding and structure of the index.
org.apache.lucene.codecs.compressing
Compressing helper classes.
org.apache.lucene.codecs.hnsw
HNSW vector helper classes.
org.apache.lucene.codecs.lucene102
Lucene 10.2 file format.
org.apache.lucene.codecs.lucene103
Lucene 10.3 file format.
org.apache.lucene.codecs.lucene103.blocktree
BlockTree terms dictionary.
org.apache.lucene.codecs.lucene90
Lucene 9.0 file format.
org.apache.lucene.codecs.lucene90.compressing
Lucene 9.0 compressing format.
org.apache.lucene.codecs.lucene94
Lucene 9.4 file format.
org.apache.lucene.codecs.lucene95
Lucene 9.5 file format.
org.apache.lucene.codecs.lucene99
Lucene 9.9 file format.
org.apache.lucene.codecs.perfield
Postings format that can delegate to different formats per-field.
org.apache.lucene.document
The logical representation of a `Document` for indexing and searching.
org.apache.lucene.geo
Core geo-spatial types and utilities for handling geographical data and spatial operations in Lucene.
org.apache.lucene.index
Code to maintain and access indices.
org.apache.lucene.internal.tests
Internal bridges to package-private internals, for use by the lucene test framework only.
org.apache.lucene.search
Code to search indices.
org.apache.lucene.search.comparators
Comparators, used to compare hits so as to determine their sort order when collecting the top results with `TopFieldCollector`.
org.apache.lucene.search.knn
Classes related to vector search: knn and vector fields.
org.apache.lucene.search.similarities
This package contains the various ranking models that can be used in Lucene.
org.apache.lucene.util
Some utility classes.
org.apache.lucene.util.automaton
Finite-state automaton for regular expressions.
org.apache.lucene.util.bkd
Block KD-tree, implementing the generic spatial data structure described in this paper.
org.apache.lucene.util.graph
Utility classes for working with token streams as graphs.
org.apache.lucene.util.hnsw
Navigable Small-World graph, nominally Hierarchical but currently only has a single layer.
org.apache.lucene.util.quantization
Provides quantization methods for scaling vector values to smaller data types and possibly fewer dimensions

- Classes in org.apache.lucene.index used by org.apache.lucene.codecs
  Class
  Description
  BinaryDocValues
  A per-document numeric value.
  ByteVectorValues
  This class provides access to per-document floating point vector values indexed as `KnnByteVectorField`.
  DocsWithFieldSet
  Accumulator for documents that have a value for a field.
  DocValuesSkipper
  Skipper for `DocValues`.
  FieldInfo
  Access to the Field Info file that describes document fields and whether or not they are indexed.
  FieldInfos
  Collection of `FieldInfo`s (accessible by number or by name).
  Fields
  Provides a `Terms` index for fields that have it, and lists which fields do.
  FloatVectorValues
  This class provides access to per-document floating point vector values indexed as `KnnFloatVectorField`.
  Impact
  Per-document scoring factors.
  ImpactsEnum
  Extension of `PostingsEnum` which also provides information about upcoming impacts.
  IndexOptions
  Controls how much information is stored in the postings lists.
  MergeState
  Holds common state used during segment merging.
  NumericDocValues
  A per-document numeric value.
  OrdinalMap
  Maps per-segment ordinals to/from global ordinal space, using a compact packed-ints representation.
  OrdTermState
  An ordinal based `TermState`
  PointValues
  Access to indexed numeric values.
  PointValues.IntersectVisitor
  We recurse the `PointValues.PointTree`, using a provided instance of this to guide the recursion.
  PointValues.PointTree
  Basic operations to read the KD-tree.
  PostingsEnum
  Iterates through the postings.
  SegmentCommitInfo
  Embeds a [read-only] SegmentInfo and adds per-commit fields.
  SegmentInfo
  Information about a segment such as its name, directory, and files related to the segment.
  SegmentReadState
  Holder class for common parameters used during read.
  SegmentWriteState
  Holder class for common parameters used during write.
  SortedDocValues
  A per-document byte[] with presorted values.
  SortedNumericDocValues
  A list of per-document numeric values, sorted according to `Long.compare(long, long)`.
  SortedSetDocValues
  A multi-valued version of `SortedDocValues`.
  Sorter.DocMap
  A permutation of doc IDs.
  StoredFieldDataInput
  A fixed size DataInput which includes the length of the input.
  StoredFields
  API for reading stored fields.
  StoredFieldVisitor
  Expert: provides a low-level means of accessing the stored field values in an index.
  StoredFieldVisitor.Status
  Enumeration of possible return values for `StoredFieldVisitor.needsField(org.apache.lucene.index.FieldInfo)`.
  TermsEnum
  Iterator to seek (`TermsEnum.seekCeil(BytesRef)`, `TermsEnum.seekExact(BytesRef)`) or step through (`BytesRefIterator.next()` terms to obtain frequency information (`TermsEnum.docFreq()`), `PostingsEnum` or `PostingsEnum` for the current term (`TermsEnum.postings(org.apache.lucene.index.PostingsEnum)`.
  TermState
  Encapsulates all required internal state to position the associated `TermsEnum` without re-seeking.
  TermVectors
  API for reading term vectors.
- Classes in org.apache.lucene.index used by org.apache.lucene.codecs.compressing
  Class
  Description
  MergeState
  Holds common state used during segment merging.
- Classes in org.apache.lucene.index used by org.apache.lucene.codecs.hnsw
  Class
  Description
  DocsWithFieldSet
  Accumulator for documents that have a value for a field.
  FieldInfo
  Access to the Field Info file that describes document fields and whether or not they are indexed.
  KnnVectorValues
  This class abstracts addressing of document vector values indexed as `KnnFloatVectorField` or `KnnByteVectorField`.
  MergeState
  Holds common state used during segment merging.
  SegmentReadState
  Holder class for common parameters used during read.
  SegmentWriteState
  Holder class for common parameters used during write.
  VectorSimilarityFunction
  Vector similarity function; used in search to return top K most similar vectors to a target vector.
- Classes in org.apache.lucene.index used by org.apache.lucene.codecs.lucene102
  Class
  Description
  ByteVectorValues
  This class provides access to per-document floating point vector values indexed as `KnnByteVectorField`.
  FieldInfo
  Access to the Field Info file that describes document fields and whether or not they are indexed.
  KnnVectorValues
  This class abstracts addressing of document vector values indexed as `KnnFloatVectorField` or `KnnByteVectorField`.
  MergeState
  Holds common state used during segment merging.
  SegmentReadState
  Holder class for common parameters used during read.
  SegmentWriteState
  Holder class for common parameters used during write.
  Sorter.DocMap
  A permutation of doc IDs.
  VectorSimilarityFunction
  Vector similarity function; used in search to return top K most similar vectors to a target vector.
- Classes in org.apache.lucene.index used by org.apache.lucene.codecs.lucene103
  Class
  Description
  FieldInfo
  Access to the Field Info file that describes document fields and whether or not they are indexed.
  ImpactsEnum
  Extension of `PostingsEnum` which also provides information about upcoming impacts.
  NumericDocValues
  A per-document numeric value.
  OrdTermState
  An ordinal based `TermState`
  PostingsEnum
  Iterates through the postings.
  SegmentReadState
  Holder class for common parameters used during read.
  SegmentWriteState
  Holder class for common parameters used during write.
  TermState
  Encapsulates all required internal state to position the associated `TermsEnum` without re-seeking.
- Classes in org.apache.lucene.index used by org.apache.lucene.codecs.lucene103.blocktree
  Class
  Description
  Fields
  Provides a `Terms` index for fields that have it, and lists which fields do.
  SegmentReadState
  Holder class for common parameters used during read.
  SegmentWriteState
  Holder class for common parameters used during write.
  Terms
  Access to the terms in a specific field.
  TermsEnum
  Iterator to seek (`TermsEnum.seekCeil(BytesRef)`, `TermsEnum.seekExact(BytesRef)`) or step through (`BytesRefIterator.next()` terms to obtain frequency information (`TermsEnum.docFreq()`), `PostingsEnum` or `PostingsEnum` for the current term (`TermsEnum.postings(org.apache.lucene.index.PostingsEnum)`.
- Classes in org.apache.lucene.index used by org.apache.lucene.codecs.lucene90
  Class
  Description
  FieldInfo
  Access to the Field Info file that describes document fields and whether or not they are indexed.
  FieldInfos
  Collection of `FieldInfo`s (accessible by number or by name).
  KnnVectorValues.DocIndexIterator
  A DocIdSetIterator that also provides an index() method tracking a distinct ordinal for a vector associated with each doc.
  MergeState
  Holds common state used during segment merging.
  PointValues
  Access to indexed numeric values.
  SegmentCommitInfo
  Embeds a [read-only] SegmentInfo and adds per-commit fields.
  SegmentInfo
  Information about a segment such as its name, directory, and files related to the segment.
  SegmentReadState
  Holder class for common parameters used during read.
  SegmentWriteState
  Holder class for common parameters used during write.
- Classes in org.apache.lucene.index used by org.apache.lucene.codecs.lucene90.compressing
  Class
  Description
  FieldInfo
  Access to the Field Info file that describes document fields and whether or not they are indexed.
  FieldInfos
  Collection of `FieldInfo`s (accessible by number or by name).
  Fields
  Provides a `Terms` index for fields that have it, and lists which fields do.
  MergeState
  Holds common state used during segment merging.
  SegmentInfo
  Information about a segment such as its name, directory, and files related to the segment.
  StoredFieldDataInput
  A fixed size DataInput which includes the length of the input.
  StoredFields
  API for reading stored fields.
  StoredFieldVisitor
  Expert: provides a low-level means of accessing the stored field values in an index.
  TermVectors
  API for reading term vectors.
- Classes in org.apache.lucene.index used by org.apache.lucene.codecs.lucene94
  Class
  Description
  FieldInfos
  Collection of `FieldInfo`s (accessible by number or by name).
  SegmentInfo
  Information about a segment such as its name, directory, and files related to the segment.
- Classes in org.apache.lucene.index used by org.apache.lucene.codecs.lucene95
  Class
  Description
  ByteVectorValues
  This class provides access to per-document floating point vector values indexed as `KnnByteVectorField`.
  DocsWithFieldSet
  Accumulator for documents that have a value for a field.
  FloatVectorValues
  This class provides access to per-document floating point vector values indexed as `KnnFloatVectorField`.
  KnnVectorValues
  This class abstracts addressing of document vector values indexed as `KnnFloatVectorField` or `KnnByteVectorField`.
  KnnVectorValues.DocIndexIterator
  A DocIdSetIterator that also provides an index() method tracking a distinct ordinal for a vector associated with each doc.
  VectorEncoding
  The numeric datatype of the vector values.
  VectorSimilarityFunction
  Vector similarity function; used in search to return top K most similar vectors to a target vector.
- Classes in org.apache.lucene.index used by org.apache.lucene.codecs.lucene99
  Class
  Description
  ByteVectorValues
  This class provides access to per-document floating point vector values indexed as `KnnByteVectorField`.
  DocsWithFieldSet
  Accumulator for documents that have a value for a field.
  FieldInfo
  Access to the Field Info file that describes document fields and whether or not they are indexed.
  FloatVectorValues
  This class provides access to per-document floating point vector values indexed as `KnnFloatVectorField`.
  KnnVectorValues
  This class abstracts addressing of document vector values indexed as `KnnFloatVectorField` or `KnnByteVectorField`.
  KnnVectorValues.DocIndexIterator
  A DocIdSetIterator that also provides an index() method tracking a distinct ordinal for a vector associated with each doc.
  MergeState
  Holds common state used during segment merging.
  SegmentInfo
  Information about a segment such as its name, directory, and files related to the segment.
  SegmentReadState
  Holder class for common parameters used during read.
  SegmentWriteState
  Holder class for common parameters used during write.
  Sorter.DocMap
  A permutation of doc IDs.
  VectorEncoding
  The numeric datatype of the vector values.
  VectorSimilarityFunction
  Vector similarity function; used in search to return top K most similar vectors to a target vector.
- Classes in org.apache.lucene.index used by org.apache.lucene.codecs.perfield
  Class
  Description
  ByteVectorValues
  This class provides access to per-document floating point vector values indexed as `KnnByteVectorField`.
  FieldInfo
  Access to the Field Info file that describes document fields and whether or not they are indexed.
  FloatVectorValues
  This class provides access to per-document floating point vector values indexed as `KnnFloatVectorField`.
  SegmentReadState
  Holder class for common parameters used during read.
  SegmentWriteState
  Holder class for common parameters used during write.
- Classes in org.apache.lucene.index used by org.apache.lucene.document
  Class
  Description
  BinaryDocValues
  A per-document numeric value.
  DocValuesSkipIndexType
  Options for skip indexes on doc values.
  DocValuesType
  DocValues types.
  FieldInfo
  Access to the Field Info file that describes document fields and whether or not they are indexed.
  IndexableField
  Represents a single field for indexing.
  IndexableFieldType
  Describes the properties of a field.
  IndexOptions
  Controls how much information is stored in the postings lists.
  StoredFieldDataInput
  A fixed size DataInput which includes the length of the input.
  StoredFieldVisitor
  Expert: provides a low-level means of accessing the stored field values in an index.
  StoredFieldVisitor.Status
  Enumeration of possible return values for `StoredFieldVisitor.needsField(org.apache.lucene.index.FieldInfo)`.
  VectorEncoding
  The numeric datatype of the vector values.
  VectorSimilarityFunction
  Vector similarity function; used in search to return top K most similar vectors to a target vector.
- Classes in org.apache.lucene.index used by org.apache.lucene.geo
  Class
  Description
  PointValues.Relation
  Used by `PointValues.intersect(org.apache.lucene.index.PointValues.IntersectVisitor)` to check how each recursive cell corresponds to the query.
- Classes in org.apache.lucene.index used by org.apache.lucene.index
  Class
  Description
  BaseCompositeReader
  Base class for implementing `CompositeReader`s based on an array of sub-readers.
  BaseTermsEnum
  A base TermsEnum that adds default implementations for `BaseTermsEnum.attributes()` `BaseTermsEnum.termState()` `BaseTermsEnum.seekExact(BytesRef)` `BaseTermsEnum.seekExact(BytesRef, TermState)` In some cases, the default implementation may be slow and consume huge memory, so subclass SHOULD have its own implementation if possible.
  BinaryDocValues
  A per-document numeric value.
  ByteVectorValues
  This class provides access to per-document floating point vector values indexed as `KnnByteVectorField`.
  CheckIndex.Options
  Run-time configuration options for CheckIndex commands.
  CheckIndex.Status
  Returned from `CheckIndex.checkIndex()` detailing the health and status of the index.
  CheckIndex.Status.DocValuesStatus
  Status from testing DocValues
  CheckIndex.Status.FieldInfoStatus
  Status from testing field infos.
  CheckIndex.Status.FieldNormStatus
  Status from testing field norms.
  CheckIndex.Status.IndexSortStatus
  Status from testing index sort
  CheckIndex.Status.LiveDocStatus
  Status from testing livedocs
  CheckIndex.Status.PointsStatus
  Status from testing PointValues
  CheckIndex.Status.SegmentInfoStatus
  Holds the status of each segment in the index.
  CheckIndex.Status.SoftDeletesStatus
  Status from testing soft deletes
  CheckIndex.Status.StoredFieldStatus
  Status from testing stored fields.
  CheckIndex.Status.TermIndexStatus
  Status from testing term index.
  CheckIndex.Status.TermVectorStatus
  Status from testing stored fields.
  CheckIndex.Status.VectorValuesStatus
  Status from testing vector values
  CodecReader
  LeafReader implemented by codec APIs.
  CompositeReader
  Instances of this reader type can only be used to get stored fields from the underlying LeafReaders, but it is not possible to directly retrieve postings.
  CompositeReaderContext
  `IndexReaderContext` for `CompositeReader` instance.
  ConcurrentMergeScheduler.MergeThread
  Runs a merge thread to execute a single merge, then exits.
  DirectoryReader
  DirectoryReader is an implementation of `CompositeReader` that can read indexes in a `Directory`.
  DocIDMerger
  Utility class to help merging documents from sub-readers according to either simple concatenated (unsorted) order, or by a specified index-time sort, skipping deleted documents and remapping non-deleted documents.
  DocIDMerger.Sub
  Represents one sub-reader being merged
  DocValuesSkipIndexType
  Options for skip indexes on doc values.
  DocValuesSkipper
  Skipper for `DocValues`.
  DocValuesType
  DocValues types.
  FieldInfo
  Access to the Field Info file that describes document fields and whether or not they are indexed.
  FieldInfos
  Collection of `FieldInfo`s (accessible by number or by name).
  Fields
  Provides a `Terms` index for fields that have it, and lists which fields do.
  FilterCodecReader
  A `FilterCodecReader` contains another CodecReader, which it uses as its basic source of data, possibly transforming the data along the way or providing additional functionality.
  FilterDirectoryReader
  A FilterDirectoryReader wraps another DirectoryReader, allowing implementations to transform or extend it.
  FilterDirectoryReader.SubReaderWrapper
  Factory class passed to FilterDirectoryReader constructor that allows subclasses to wrap the filtered DirectoryReader's subreaders.
  FilteredTermsEnum
  Abstract class for enumerating a subset of all terms.
  FilteredTermsEnum.AcceptStatus
  Return value, if term should be accepted or the iteration should `END`.
  FilterLeafReader
  A `FilterLeafReader` contains another LeafReader, which it uses as its basic source of data, possibly transforming the data along the way or providing additional functionality.
  FilterLeafReader.FilterFields
  Base class for filtering `Fields` implementations.
  FilterLeafReader.FilterTerms
  Base class for filtering `Terms` implementations.
  FilterLeafReader.FilterTermsEnum
  Base class for filtering `TermsEnum` implementations.
  FilterMergePolicy
  A wrapper for `MergePolicy` instances.
  FloatVectorValues
  This class provides access to per-document floating point vector values indexed as `KnnFloatVectorField`.
  Impact
  Per-document scoring factors.
  Impacts
  Information about upcoming impacts, ie.
  ImpactsEnum
  Extension of `PostingsEnum` which also provides information about upcoming impacts.
  ImpactsSource
  Source of `Impacts`.
  IndexableField
  Represents a single field for indexing.
  IndexableFieldType
  Describes the properties of a field.
  IndexCommit
  Expert: represents a single commit into an index as seen by the `IndexDeletionPolicy` or `IndexReader`.
  IndexDeletionPolicy
  Expert: policy for deletion of stale `index commits`.
  IndexOptions
  Controls how much information is stored in the postings lists.
  IndexReader
  IndexReader is an abstract class, providing an interface for accessing a point-in-time view of an index.
  IndexReader.CacheHelper
  A utility class that gives hooks in order to help build a cache based on the data that is contained in this index.
  IndexReader.CacheKey
  A cache key identifying a resource that is being cached on.
  IndexReader.ClosedListener
  A listener that is called when a resource gets closed.
  IndexReaderContext
  A struct like class that represents a hierarchical relationship between `IndexReader` instances.
  IndexSorter
  Handles how documents should be sorted in an index, both within a segment and between segments.
  IndexSorter.ComparableProvider
  Used for sorting documents across segments
  IndexSorter.DocComparator
  A comparator of doc IDs, used for sorting documents within a segment
  IndexSorter.NumericDocValuesProvider
  Provide a NumericDocValues instance for a LeafReader
  IndexSorter.SortedDocValuesProvider
  Provide a SortedDocValues instance for a LeafReader
  IndexWriter
  An `IndexWriter` creates and maintains an index.
  IndexWriter.DocStats
  DocStats for this index
  IndexWriter.IndexReaderWarmer
  If `DirectoryReader.open(IndexWriter)` has been called (ie, this writer is in near real-time mode), then after a merge completes, this class can be invoked to warm the reader on the newly merged segment, before the merge commits.
  IndexWriterConfig
  Holds all the configuration that is used to create an `IndexWriter`.
  IndexWriterConfig.OpenMode
  Specifies the open mode for `IndexWriter`.
  IndexWriterEventListener
  A callback event listener for recording key events happened inside IndexWriter
  KnnVectorValues
  This class abstracts addressing of document vector values indexed as `KnnFloatVectorField` or `KnnByteVectorField`.
  KnnVectorValues.DocIndexIterator
  A DocIdSetIterator that also provides an index() method tracking a distinct ordinal for a vector associated with each doc.
  LeafMetaData
  Provides read-only metadata about a leaf.
  LeafReader
  `LeafReader` is an abstract class, providing an interface for accessing an index.
  LeafReaderContext
  `IndexReaderContext` for `LeafReader` instances.
  LiveIndexWriterConfig
  Holds all the configuration used by `IndexWriter` with few setters for settings that can be changed on an `IndexWriter` instance "live".
  LogMergePolicy
  This class implements a `MergePolicy` that tries to merge segments into levels of exponentially increasing size, where each level has fewer segments than the value of the merge factor.
  MergePolicy
  Expert: a MergePolicy determines the sequence of primitive merge operations.
  MergePolicy.MergeAbortedException
  Thrown when a merge was explicitly aborted because `IndexWriter.abortMerges()` was called.
  MergePolicy.MergeContext
  This interface represents the current context of the merge selection process.
  MergePolicy.MergeSpecification
  A MergeSpecification instance provides the information necessary to perform multiple merges.
  MergePolicy.OneMerge
  OneMerge provides the information necessary to perform an individual primitive merge operation, resulting in a single new segment.
  MergePolicy.OneMergeProgress
  Progress and state for an executing merge.
  MergePolicy.OneMergeProgress.PauseReason
  Reason for pausing the merge thread.
  MergeScheduler
  Expert: `IndexWriter` uses an instance implementing this interface to execute the merges selected by a `MergePolicy`.
  MergeScheduler.MergeSource
  Provides access to new merges and executes the actual merge
  MergeState
  Holds common state used during segment merging.
  MergeState.DocMap
  A map of doc IDs.
  MergeTrigger
  MergeTrigger is passed to `MergePolicy.findMerges(MergeTrigger, SegmentInfos, MergePolicy.MergeContext)` to indicate the event that triggered the merge.
  MultiFields
  Provides a single `Fields` term index view over an `IndexReader`.
  MultiPostingsEnum
  Exposes `PostingsEnum`, merged from `PostingsEnum` API of sub-segments.
  MultiPostingsEnum.EnumWithSlice
  Holds a `PostingsEnum` along with the corresponding `ReaderSlice`.
  MultiTermsEnum
  Exposes `TermsEnum` API, merged from `TermsEnum` API of sub-segments.
  NumericDocValues
  A per-document numeric value.
  OneMergeWrappingMergePolicy
  A wrapping merge policy that wraps the `MergePolicy.OneMerge` objects returned by the wrapped merge policy.
  OrdinalMap
  Maps per-segment ordinals to/from global ordinal space, using a compact packed-ints representation.
  PointValues
  Access to indexed numeric values.
  PointValues.IntersectVisitor
  We recurse the `PointValues.PointTree`, using a provided instance of this to guide the recursion.
  PointValues.PointTree
  Basic operations to read the KD-tree.
  PointValues.Relation
  Used by `PointValues.intersect(org.apache.lucene.index.PointValues.IntersectVisitor)` to check how each recursive cell corresponds to the query.
  PostingsEnum
  Iterates through the postings.
  PrefixCodedTerms
  Prefix codes term instances (prefixes are shared).
  PrefixCodedTerms.TermIterator
  An iterator over the list of terms stored in a `PrefixCodedTerms`.
  QueryTimeout
  Query timeout abstraction that controls whether a query should continue or be stopped.
  ReaderSlice
  Subreader slice from a parent composite reader.
  SegmentCommitInfo
  Embeds a [read-only] SegmentInfo and adds per-commit fields.
  SegmentInfo
  Information about a segment such as its name, directory, and files related to the segment.
  SegmentInfos
  A collection of segmentInfo objects with methods for operating on those segments in relation to the file system.
  SegmentReadState
  Holder class for common parameters used during read.
  SegmentWriteState
  Holder class for common parameters used during write.
  SnapshotDeletionPolicy
  An `IndexDeletionPolicy` that wraps any other `IndexDeletionPolicy` and adds the ability to hold and later release snapshots of an index.
  SortedDocValues
  A per-document byte[] with presorted values.
  SortedNumericDocValues
  A list of per-document numeric values, sorted according to `Long.compare(long, long)`.
  SortedSetDocValues
  A multi-valued version of `SortedDocValues`.
  Sorter.DocMap
  A permutation of doc IDs.
  SortFieldProvider
  Reads/Writes a named SortField from a segment info file, used to record index sorts
  StoredFieldDataInput
  A fixed size DataInput which includes the length of the input.
  StoredFields
  API for reading stored fields.
  StoredFieldVisitor
  Expert: provides a low-level means of accessing the stored field values in an index.
  StoredFieldVisitor.Status
  Enumeration of possible return values for `StoredFieldVisitor.needsField(org.apache.lucene.index.FieldInfo)`.
  Term
  A Term represents a word from text.
  Terms
  Access to the terms in a specific field.
  TermsEnum
  Iterator to seek (`TermsEnum.seekCeil(BytesRef)`, `TermsEnum.seekExact(BytesRef)`) or step through (`BytesRefIterator.next()` terms to obtain frequency information (`TermsEnum.docFreq()`), `PostingsEnum` or `PostingsEnum` for the current term (`TermsEnum.postings(org.apache.lucene.index.PostingsEnum)`.
  TermsEnum.SeekStatus
  Represents returned result from `TermsEnum.seekCeil(org.apache.lucene.util.BytesRef)`.
  TermState
  Encapsulates all required internal state to position the associated `TermsEnum` without re-seeking.
  TermStates
  Maintains a `IndexReader` `TermState` view over `IndexReader` instances containing a single term.
  TermVectors
  API for reading term vectors.
  TieredMergePolicy
  Merges segments of approximately equal size, subject to an allowed number of segments per tier.
  TieredMergePolicy.MergeScore
  Holds score and explanation for a single candidate merge.
  TwoPhaseCommit
  An interface for implementations that support 2-phase commit.
  TwoPhaseCommitTool.CommitFailException
  Thrown by `TwoPhaseCommitTool.execute(TwoPhaseCommit...)` when an object fails to commit().
  TwoPhaseCommitTool.PrepareCommitFailException
  Thrown by `TwoPhaseCommitTool.execute(TwoPhaseCommit...)` when an object fails to prepareCommit().
  VectorEncoding
  The numeric datatype of the vector values.
  VectorSimilarityFunction
  Vector similarity function; used in search to return top K most similar vectors to a target vector.
- Classes in org.apache.lucene.index used by org.apache.lucene.internal.tests
  Class
  Description
  ConcurrentMergeScheduler
  A `MergeScheduler` that runs each merge using a separate thread.
  DirectoryReader
  DirectoryReader is an implementation of `CompositeReader` that can read indexes in a `Directory`.
  FieldInfo
  Access to the Field Info file that describes document fields and whether or not they are indexed.
  FieldInfos
  Collection of `FieldInfo`s (accessible by number or by name).
  Impacts
  Information about upcoming impacts, ie.
  IndexReader.CacheKey
  A cache key identifying a resource that is being cached on.
  IndexWriter
  An `IndexWriter` creates and maintains an index.
  SegmentCommitInfo
  Embeds a [read-only] SegmentInfo and adds per-commit fields.
  SegmentReader
  IndexReader implementation over a single segment.
- Classes in org.apache.lucene.index used by org.apache.lucene.search
  Class
  Description
  BaseTermsEnum
  A base TermsEnum that adds default implementations for `BaseTermsEnum.attributes()` `BaseTermsEnum.termState()` `BaseTermsEnum.seekExact(BytesRef)` `BaseTermsEnum.seekExact(BytesRef, TermState)` In some cases, the default implementation may be slow and consume huge memory, so subclass SHOULD have its own implementation if possible.
  BinaryDocValues
  A per-document numeric value.
  DirectoryReader
  DirectoryReader is an implementation of `CompositeReader` that can read indexes in a `Directory`.
  DocValuesSkipper
  Skipper for `DocValues`.
  ImpactsEnum
  Extension of `PostingsEnum` which also provides information about upcoming impacts.
  ImpactsSource
  Source of `Impacts`.
  IndexCommit
  Expert: represents a single commit into an index as seen by the `IndexDeletionPolicy` or `IndexReader`.
  IndexReader
  IndexReader is an abstract class, providing an interface for accessing a point-in-time view of an index.
  IndexReaderContext
  A struct like class that represents a hierarchical relationship between `IndexReader` instances.
  IndexSorter
  Handles how documents should be sorted in an index, both within a segment and between segments.
  IndexWriter
  An `IndexWriter` creates and maintains an index.
  LeafReader
  `LeafReader` is an abstract class, providing an interface for accessing an index.
  LeafReaderContext
  `IndexReaderContext` for `LeafReader` instances.
  NumericDocValues
  A per-document numeric value.
  PostingsEnum
  Iterates through the postings.
  QueryTimeout
  Query timeout abstraction that controls whether a query should continue or be stopped.
  SortedDocValues
  A per-document byte[] with presorted values.
  SortedNumericDocValues
  A list of per-document numeric values, sorted according to `Long.compare(long, long)`.
  SortedSetDocValues
  A multi-valued version of `SortedDocValues`.
  SortFieldProvider
  Reads/Writes a named SortField from a segment info file, used to record index sorts
  StoredFields
  API for reading stored fields.
  Term
  A Term represents a word from text.
  Terms
  Access to the terms in a specific field.
  TermsEnum
  Iterator to seek (`TermsEnum.seekCeil(BytesRef)`, `TermsEnum.seekExact(BytesRef)`) or step through (`BytesRefIterator.next()` terms to obtain frequency information (`TermsEnum.docFreq()`), `PostingsEnum` or `PostingsEnum` for the current term (`TermsEnum.postings(org.apache.lucene.index.PostingsEnum)`.
  TermsEnum.SeekStatus
  Represents returned result from `TermsEnum.seekCeil(org.apache.lucene.util.BytesRef)`.
  TermState
  Encapsulates all required internal state to position the associated `TermsEnum` without re-seeking.
  TermStates
  Maintains a `IndexReader` `TermState` view over `IndexReader` instances containing a single term.
  VectorSimilarityFunction
  Vector similarity function; used in search to return top K most similar vectors to a target vector.
- Classes in org.apache.lucene.index used by org.apache.lucene.search.comparators
  Class
  Description
  LeafReaderContext
  `IndexReaderContext` for `LeafReader` instances.
  NumericDocValues
  A per-document numeric value.
  SortedDocValues
  A per-document byte[] with presorted values.
- Classes in org.apache.lucene.index used by org.apache.lucene.search.knn
  Class
  Description
  LeafReaderContext
  `IndexReaderContext` for `LeafReader` instances.
- Classes in org.apache.lucene.index used by org.apache.lucene.search.similarities
  Class
  Description
  FieldInvertState
  This class tracks the number and position / offset parameters of terms being added to the index.
- Classes in org.apache.lucene.index used by org.apache.lucene.util
  Class
  Description
  PointValues
  Access to indexed numeric values.
  Term
  A Term represents a word from text.
  Terms
  Access to the terms in a specific field.
- Classes in org.apache.lucene.index used by org.apache.lucene.util.automaton
  Class
  Description
  Terms
  Access to the terms in a specific field.
  TermsEnum
  Iterator to seek (`TermsEnum.seekCeil(BytesRef)`, `TermsEnum.seekExact(BytesRef)`) or step through (`BytesRefIterator.next()` terms to obtain frequency information (`TermsEnum.docFreq()`), `PostingsEnum` or `PostingsEnum` for the current term (`TermsEnum.postings(org.apache.lucene.index.PostingsEnum)`.
- Classes in org.apache.lucene.index used by org.apache.lucene.util.bkd
  Class
  Description
  MergeState.DocMap
  A map of doc IDs.
  PointValues
  Access to indexed numeric values.
  PointValues.PointTree
  Basic operations to read the KD-tree.
- Classes in org.apache.lucene.index used by org.apache.lucene.util.graph
  Class
  Description
  Term
  A Term represents a word from text.
- Classes in org.apache.lucene.index used by org.apache.lucene.util.hnsw
  Class
  Description
  FieldInfo
  Access to the Field Info file that describes document fields and whether or not they are indexed.
  IndexReader
  IndexReader is an abstract class, providing an interface for accessing a point-in-time view of an index.
  KnnVectorValues
  This class abstracts addressing of document vector values indexed as `KnnFloatVectorField` or `KnnByteVectorField`.
  MergeState.DocMap
  A map of doc IDs.
- Classes in org.apache.lucene.index used by org.apache.lucene.util.quantization
  Class
  Description
  ByteVectorValues
  This class provides access to per-document floating point vector values indexed as `KnnByteVectorField`.
  FloatVectorValues
  This class provides access to per-document floating point vector values indexed as `KnnFloatVectorField`.
  KnnVectorValues
  This class abstracts addressing of document vector values indexed as `KnnFloatVectorField` or `KnnByteVectorField`.
  VectorSimilarityFunction
  Vector similarity function; used in search to return top K most similar vectors to a target vector.