# Uses of Package
org.apache.lucene.codecs

- Packages that use org.apache.lucene.codecs
  Package | Description
  --- | ---
  org.apache.lucene.codecs | Codecs API: API for customization of the encoding and structure of the index.
  org.apache.lucene.codecs.lucene90 | Lucene 9.0 file format.
  org.apache.lucene.codecs.lucene90.blocktree | BlockTree terms dictionary.
  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.lucene99 | Lucene 9.9 file format.
  org.apache.lucene.codecs.perfield | Postings format that can delegate to different formats per-field.
  org.apache.lucene.index | Code to maintain and access indices.
  org.apache.lucene.util.bkd | Block KD-tree, implementing the generic spatial data structure described in this paper.
  org.apache.lucene.util.hnsw | Navigable Small-World graph, nominally Hierarchical but currently only has a single layer.

- Classes in org.apache.lucene.codecs used by org.apache.lucene.codecs
  Class | Description
  --- | ---
  BlockTermState | Holds all state required for `PostingsReaderBase` to produce a `PostingsEnum` without re-seeking the terms dict.
  Codec | Encodes/decodes an inverted index segment.
  CompetitiveImpactAccumulator | This class accumulates the (freq, norm) pairs that may produce competitive scores.
  CompoundDirectory | A read-only `Directory` that consists of a view over a compound file.
  CompoundFormat | Encodes/decodes compound files
  DocValuesConsumer | Abstract API that consumes numeric, binary and sorted docvalues.
  DocValuesFormat | Encodes/decodes per-document values.
  DocValuesProducer | Abstract API that produces numeric, binary, sorted, sortedset, and sortednumeric docvalues.
  FieldInfosFormat | Encodes/decodes `FieldInfos`
  FieldsConsumer | Abstract API that consumes terms, doc, freq, prox, offset and payloads postings.
  FieldsProducer | Abstract API that produces terms, doc, freq, prox, offset and payloads postings.
  FlatFieldVectorsWriter | Vectors' writer for a field
  FlatVectorsReader | Reads vectors from an index.
  FlatVectorsWriter | Vectors' writer for a field that allows additional indexing logic to be implemented by the caller
  KnnFieldVectorsWriter | Vectors' writer for a field
  KnnVectorsFormat | Encodes/decodes per-document vector and any associated indexing structures required to support nearest-neighbor search
  KnnVectorsReader | Reads vectors from an index.
  KnnVectorsWriter | Writes vectors to an index.
  LiveDocsFormat | Format for live/deleted documents
  NormsConsumer | Abstract API that consumes normalization values.
  NormsFormat | Encodes/decodes per-document score normalization values.
  NormsProducer | Abstract API that produces field normalization values
  PointsFormat | Encodes/decodes indexed points.
  PointsReader | Abstract API to visit point values.
  PointsWriter | Abstract API to write points
  PostingsFormat | Encodes/decodes terms, postings, and proximity data.
  PostingsWriterBase | Class that plugs into term dictionaries, such as `Lucene90BlockTreeTermsWriter`, and handles writing postings.
  SegmentInfoFormat | Expert: Controls the format of the `SegmentInfo` (segment metadata file).
  StoredFieldsFormat | Controls the format of stored fields
  StoredFieldsReader | Codec API for reading stored fields.
  StoredFieldsWriter | Codec API for writing stored fields: For every document, `StoredFieldsWriter.startDocument()` is called, informing the Codec that a new document has started.
  TermVectorsFormat | Controls the format of term vectors
  TermVectorsReader | Codec API for reading term vectors:
  TermVectorsWriter | Codec API for writing term vectors: For every document, `TermVectorsWriter.startDocument(int)` is called, informing the Codec how many fields will be written.

- Classes in org.apache.lucene.codecs used by org.apache.lucene.codecs.lucene90
  Class | Description
  --- | ---
  CompoundDirectory | A read-only `Directory` that consists of a view over a compound file.
  CompoundFormat | Encodes/decodes compound files
  DocValuesConsumer | Abstract API that consumes numeric, binary and sorted docvalues.
  DocValuesFormat | Encodes/decodes per-document values.
  DocValuesProducer | Abstract API that produces numeric, binary, sorted, sortedset, and sortednumeric docvalues.
  LiveDocsFormat | Format for live/deleted documents
  NormsConsumer | Abstract API that consumes normalization values.
  NormsFormat | Encodes/decodes per-document score normalization values.
  NormsProducer | Abstract API that produces field normalization values
  PointsFormat | Encodes/decodes indexed points.
  PointsReader | Abstract API to visit point values.
  PointsWriter | Abstract API to write points
  StoredFieldsFormat | Controls the format of stored fields
  StoredFieldsReader | Codec API for reading stored fields.
  StoredFieldsWriter | Codec API for writing stored fields: For every document, `StoredFieldsWriter.startDocument()` is called, informing the Codec that a new document has started.
  TermVectorsFormat | Controls the format of term vectors

- Classes in org.apache.lucene.codecs used by org.apache.lucene.codecs.lucene90.blocktree
  Class | Description
  --- | ---
  FieldsConsumer | Abstract API that consumes terms, doc, freq, prox, offset and payloads postings.
  FieldsProducer | Abstract API that produces terms, doc, freq, prox, offset and payloads postings.
  NormsProducer | Abstract API that produces field normalization values
  PostingsReaderBase | The core terms dictionaries (BlockTermsReader, BlockTreeTermsReader) interact with a single instance of this class to manage creation of `PostingsEnum` and `PostingsEnum` instances.
  PostingsWriterBase | Class that plugs into term dictionaries, such as `Lucene90BlockTreeTermsWriter`, and handles writing postings.

- Classes in org.apache.lucene.codecs used by org.apache.lucene.codecs.lucene90.compressing
  Class | Description
  --- | ---
  StoredFieldsFormat | Controls the format of stored fields
  StoredFieldsReader | Codec API for reading stored fields.
  StoredFieldsWriter | Codec API for writing stored fields: For every document, `StoredFieldsWriter.startDocument()` is called, informing the Codec that a new document has started.
  TermVectorsFormat | Controls the format of term vectors
  TermVectorsReader | Codec API for reading term vectors:
  TermVectorsWriter | Codec API for writing term vectors: For every document, `TermVectorsWriter.startDocument(int)` is called, informing the Codec how many fields will be written.

- Classes in org.apache.lucene.codecs used by org.apache.lucene.codecs.lucene94
  Class | Description
  --- | ---
  FieldInfosFormat | Encodes/decodes `FieldInfos`

- Classes in org.apache.lucene.codecs used by org.apache.lucene.codecs.lucene99
  Class | Description
  --- | ---
  BlockTermState | Holds all state required for `PostingsReaderBase` to produce a `PostingsEnum` without re-seeking the terms dict.
  Codec | Encodes/decodes an inverted index segment.
  CompetitiveImpactAccumulator | This class accumulates the (freq, norm) pairs that may produce competitive scores.
  CompoundFormat | Encodes/decodes compound files
  DocValuesFormat | Encodes/decodes per-document values.
  FieldInfosFormat | Encodes/decodes `FieldInfos`
  FieldsConsumer | Abstract API that consumes terms, doc, freq, prox, offset and payloads postings.
  FieldsProducer | Abstract API that produces terms, doc, freq, prox, offset and payloads postings.
  FlatFieldVectorsWriter | Vectors' writer for a field
  FlatVectorsFormat | Encodes/decodes per-document vectors
  FlatVectorsReader | Reads vectors from an index.
  FlatVectorsWriter | Vectors' writer for a field that allows additional indexing logic to be implemented by the caller
  HnswGraphProvider | An interface that provides an HNSW graph.
  KnnFieldVectorsWriter | Vectors' writer for a field
  KnnVectorsFormat | Encodes/decodes per-document vector and any associated indexing structures required to support nearest-neighbor search
  KnnVectorsReader | Reads vectors from an index.
  KnnVectorsWriter | Writes vectors to an index.
  LiveDocsFormat | Format for live/deleted documents
  MultiLevelSkipListReader | This abstract class reads skip lists with multiple levels.
  MultiLevelSkipListWriter | This abstract class writes skip lists with multiple levels.
  NormsFormat | Encodes/decodes per-document score normalization values.
  PointsFormat | Encodes/decodes indexed points.
  PostingsFormat | Encodes/decodes terms, postings, and proximity data.
  PostingsReaderBase | The core terms dictionaries (BlockTermsReader, BlockTreeTermsReader) interact with a single instance of this class to manage creation of `PostingsEnum` and `PostingsEnum` instances.
  PostingsWriterBase | Class that plugs into term dictionaries, such as `Lucene90BlockTreeTermsWriter`, and handles writing postings.
  PushPostingsWriterBase | Extension of `PostingsWriterBase`, adding a push API for writing each element of the postings.
  SegmentInfoFormat | Expert: Controls the format of the `SegmentInfo` (segment metadata file).
  StoredFieldsFormat | Controls the format of stored fields
  TermVectorsFormat | Controls the format of term vectors

- Classes in org.apache.lucene.codecs used by org.apache.lucene.codecs.perfield
  Class | Description
  --- | ---
  DocValuesConsumer | Abstract API that consumes numeric, binary and sorted docvalues.
  DocValuesFormat | Encodes/decodes per-document values.
  DocValuesProducer | Abstract API that produces numeric, binary, sorted, sortedset, and sortednumeric docvalues.
  FieldsConsumer | Abstract API that consumes terms, doc, freq, prox, offset and payloads postings.
  FieldsProducer | Abstract API that produces terms, doc, freq, prox, offset and payloads postings.
  KnnVectorsFormat | Encodes/decodes per-document vector and any associated indexing structures required to support nearest-neighbor search
  KnnVectorsReader | Reads vectors from an index.
  KnnVectorsWriter | Writes vectors to an index.
  PostingsFormat | Encodes/decodes terms, postings, and proximity data.

- Classes in org.apache.lucene.codecs used by org.apache.lucene.index
  Class | Description
  --- | ---
  Codec | Encodes/decodes an inverted index segment.
  DocValuesProducer | Abstract API that produces numeric, binary, sorted, sortedset, and sortednumeric docvalues.
  FieldsProducer | Abstract API that produces terms, doc, freq, prox, offset and payloads postings.
  KnnVectorsReader | Reads vectors from an index.
  NormsProducer | Abstract API that produces field normalization values
  PointsReader | Abstract API to visit point values.
  StoredFieldsReader | Codec API for reading stored fields.
  TermVectorsReader | Codec API for reading term vectors:

- Classes in org.apache.lucene.codecs used by org.apache.lucene.util.bkd
  Class | Description
  --- | ---
  MutablePointTree | One leaf `PointValues.PointTree` whose order of points can be changed.

- Classes in org.apache.lucene.codecs used by org.apache.lucene.util.hnsw
  Class | Description
  --- | ---
  KnnVectorsReader | Reads vectors from an index.