Package org.apache.lucene.codecs

Class KnnVectorsFormat

java.lang.Object

org.apache.lucene.codecs.KnnVectorsFormat

All Implemented Interfaces:

NamedSPILoader.NamedSPI

Direct Known Subclasses:

Lucene99HnswScalarQuantizedVectorsFormat, Lucene99HnswVectorsFormat, PerFieldKnnVectorsFormat

public abstract class KnnVectorsFormat
extends Object
implements NamedSPILoader.NamedSPI

Encodes/decodes per-document vector and any associated indexing structures required to support nearest-neighbor search

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_MAX_DIMENSIONS	The maximum number of vector dimensions
static final KnnVectorsFormat	EMPTY	EMPTY throws an exception when written.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	KnnVectorsFormat(String name)	Sole constructor

Method Summary

Modifier and Type	Method	Description
static Set<String>	availableKnnVectorsFormats()	returns a list of all available format names
abstract KnnVectorsReader	fieldsReader(SegmentReadState state)	Returns a KnnVectorsReader to read the vectors from the index.
abstract KnnVectorsWriter	fieldsWriter(SegmentWriteState state)	Returns a KnnVectorsWriter to write the vectors to the index.
static KnnVectorsFormat	forName(String name)	looks up a format by name
int	getMaxDimensions(String fieldName)	Returns the maximum number of vector dimensions supported by this codec for the given field name
String	getName()
static void	reloadKnnVectorsFormat(ClassLoader classloader)	Reloads the KnnVectorsFormat list from the given ClassLoader.

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_MAX_DIMENSIONS

public static final int DEFAULT_MAX_DIMENSIONS

The maximum number of vector dimensions

See Also:

• Constant Field Values

EMPTY

public static final KnnVectorsFormat EMPTY

EMPTY throws an exception when written. It acts as a sentinel indicating a Codec that does not support vectors.

Constructor Details

KnnVectorsFormat

protected KnnVectorsFormat(String name)

Sole constructor

Method Details

getName

public String getName()

Specified by:

getName in interface NamedSPILoader.NamedSPI

reloadKnnVectorsFormat

public static void reloadKnnVectorsFormat(ClassLoader classloader)

Reloads the KnnVectorsFormat list from the given ClassLoader.

NOTE: Only new KnnVectorsFormat are added, existing ones are never removed or replaced.

This method is expensive and should only be called for discovery of new KnnVectorsFormat on the given classpath/classloader!

forName

public static KnnVectorsFormat forName(String name)

looks up a format by name

availableKnnVectorsFormats

public static Set<String> availableKnnVectorsFormats()

returns a list of all available format names

fieldsWriter

public abstract KnnVectorsWriter fieldsWriter(SegmentWriteState state)
                                       throws IOException

Returns a KnnVectorsWriter to write the vectors to the index.

Throws:

IOException

fieldsReader

public abstract KnnVectorsReader fieldsReader(SegmentReadState state)
                                       throws IOException

Returns a KnnVectorsReader to read the vectors from the index.

Throws:

IOException

getMaxDimensions

public int getMaxDimensions(String fieldName)

Returns the maximum number of vector dimensions supported by this codec for the given field name

Codecs should override this method to specify the maximum number of dimensions they support.

Parameters:

fieldName - the field name

Returns:

the maximum number of vector dimensions.