OrdToDocDISIReaderConfiguration (Lucene 10.5.1 core API)
Description: declaration: package: org.apache.lucene.codecs.lucene95, class: OrdToDocDISIReaderConfiguration

Package org.apache.lucene.codecs.lucene95

# Class OrdToDocDISIReaderConfiguration

java.lang.Object
org.apache.lucene.codecs.lucene95.OrdToDocDISIReaderConfiguration

public class OrdToDocDISIReaderConfiguration extends Object
Configuration for `DirectMonotonicReader` and `IndexedDISI` for reading sparse vectors. The format in the static writing methods adheres to the Lucene95HnswVectorsFormat

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static OrdToDocDISIReaderConfiguration`
  `fromStoredMeta(IndexInput inputMeta, int size)`
  Reads in the necessary fields stored in the outputMeta to configure `DirectMonotonicReader` and `IndexedDISI`.
  `DirectMonotonicReader`
  `getDirectMonotonicReader(IndexInput dataIn)`
  `IndexedDISI`
  `getIndexedDISI(IndexInput dataIn)`
  `boolean`
  `isDense()`
  `boolean`
  `isEmpty()`
  `static void`
  `writeStoredMeta(int directMonotonicBlockShift, IndexOutput outputMeta, IndexOutput vectorData, int count, int maxDoc, DocsWithFieldSet docsWithField)`
  Writes out the docsWithField and ordToDoc mapping to the outputMeta and vectorData respectively.

  ### Methods inherited from class java.lang.Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Method Details

  - ### writeStoredMeta

    public static void writeStoredMeta(int directMonotonicBlockShift, IndexOutput outputMeta, IndexOutput vectorData, int count, int maxDoc, DocsWithFieldSet docsWithField) throws IOException
    Writes out the docsWithField and ordToDoc mapping to the outputMeta and vectorData respectively. This is in adherence to the Lucene95HnswVectorsFormat.

    Within outputMeta the format is as follows:

    - [int8] if equals to -2, empty - no vector values. If equals to -1, dense – all documents have values for a field. If equals to 0, sparse – some documents missing values.
    - DocIds were encoded by `IndexedDISI.writeBitSet(DocIdSetIterator, IndexOutput, byte)`
    - OrdToDoc was encoded by `DirectMonotonicWriter`, note that only in sparse case

    Within the vectorData the format is as follows:

    - DocIds encoded by `IndexedDISI.writeBitSet(DocIdSetIterator, IndexOutput, byte)`, note that only in sparse case
    - OrdToDoc was encoded by `DirectMonotonicWriter`, note that only in sparse case
    Parameters:
      `outputMeta` - the outputMeta
      `vectorData` - the vectorData
      `count` - the count of docs with vectors
      `maxDoc` - the maxDoc for the index
      `docsWithField` - the docs contaiting a vector field
    Throws:
      `IOException` - thrown when writing data fails to either output

  - ### fromStoredMeta

    public static OrdToDocDISIReaderConfiguration fromStoredMeta(IndexInput inputMeta, int size) throws IOException
    Reads in the necessary fields stored in the outputMeta to configure `DirectMonotonicReader` and `IndexedDISI`.
    Parameters:
      `inputMeta` - the inputMeta, previously written to via `writeStoredMeta(int, IndexOutput, IndexOutput, int, int, DocsWithFieldSet)`
      `size` - The number of vectors
    Returns:
      the configuration required to read sparse vectors
    Throws:
      `IOException` - thrown when reading data fails

  - ### getIndexedDISI

    public IndexedDISI getIndexedDISI(IndexInput dataIn) throws IOException
    Parameters:
      `dataIn` - the dataIn
    Returns:
      the IndexedDISI for sparse values
    Throws:
      `IOException` - thrown when reading data fails

  - ### getDirectMonotonicReader

    public DirectMonotonicReader getDirectMonotonicReader(IndexInput dataIn) throws IOException
    Parameters:
      `dataIn` - the dataIn
    Returns:
      the DirectMonotonicReader for sparse values
    Throws:
      `IOException` - thrown when reading data fails

  - ### isEmpty

    public boolean isEmpty()
    Returns:
      If true, the field is empty, no vector values. If false, the field is either dense or sparse.

  - ### isDense

    public boolean isDense()
    Returns:
      If true, the field is dense, all documents have values for a field. If false, the field is sparse, some documents missing values.