Package org.apache.lucene.codecs.lucene90

Class Lucene90FieldInfosFormat

java.lang.Object

org.apache.lucene.codecs.FieldInfosFormat

org.apache.lucene.codecs.lucene90.Lucene90FieldInfosFormat

public final class Lucene90FieldInfosFormat
extends FieldInfosFormat

Lucene 9.0 Field Infos format.

Field names are stored in the field info file, with suffix .fnm.

FieldInfos (.fnm) --> Header,FieldsCount, <FieldName,FieldNumber, FieldBits,DocValuesBits,DocValuesGen,Attributes,DimensionCount,DimensionNumBytes> ^FieldsCount,Footer

Data types:

• Header --> IndexHeader
• FieldsCount --> VInt
• FieldName --> String
• FieldBits, IndexOptions, DocValuesBits --> Byte
• FieldNumber, DimensionCount, DimensionNumBytes --> VInt
• Attributes --> Map<String,String>
• DocValuesGen --> Int64
• Footer --> CodecFooter

Field Descriptions:

• FieldsCount: the number of fields in this file.
• FieldName: name of the field as a UTF-8 String.
• FieldNumber: the field's number. Note that unlike previous versions of Lucene, the fields are not numbered implicitly by their order in the file, instead explicitly.
• FieldBits: a byte containing field options.
  • The low order bit (0x1) is one for fields that have term vectors stored, and zero for fields without term vectors.
  • If the second lowest order-bit is set (0x2), norms are omitted for the indexed field.
  • If the third lowest-order bit is set (0x4), payloads are stored for the indexed field.
• IndexOptions: a byte containing index options.
  • 0: not indexed
  • 1: indexed as DOCS_ONLY
  • 2: indexed as DOCS_AND_FREQS
  • 3: indexed as DOCS_AND_FREQS_AND_POSITIONS
  • 4: indexed as DOCS_AND_FREQS_AND_POSITIONS_AND_OFFSETS
• DocValuesBits: a byte containing per-document value types. The type recorded as two four-bit integers, with the high-order bits representing norms options, and the low-order bits representing DocValues options. Each four-bit integer can be decoded as such:
  • 0: no DocValues for this field.
  • 1: NumericDocValues. (DocValuesType.NUMERIC)
  • 2: BinaryDocValues. (DocValuesType#BINARY)
  • 3: SortedDocValues. (DocValuesType#SORTED)
• DocValuesGen is the generation count of the field's DocValues. If this is -1, there are no DocValues updates to that field. Anything above zero means there are updates stored by DocValuesFormat.
• Attributes: a key-value map of codec-private attributes.
• PointDimensionCount, PointNumBytes: these are non-zero only if the field is indexed as points, e.g. using LongPoint
• VectorDimension: it is non-zero if the field is indexed as vectors.
• VectorSimilarityFunction: a byte containing distance function used for similarity calculation.
  • 0: EUCLIDEAN distance. (VectorSimilarityFunction.EUCLIDEAN)
  • 1: DOT_PRODUCT similarity. (VectorSimilarityFunction.DOT_PRODUCT)
  • 2: COSINE similarity. (VectorSimilarityFunction.COSINE)

WARNING: This API is experimental and might change in incompatible ways in the next release.

Constructor Summary

Constructors

Constructor	Description
Lucene90FieldInfosFormat()	Sole constructor.

Method Summary

Modifier and Type	Method	Description
FieldInfos	read(Directory directory, SegmentInfo segmentInfo, String segmentSuffix, IOContext context)	Read the FieldInfos previously written with FieldInfosFormat.write(org.apache.lucene.store.Directory, org.apache.lucene.index.SegmentInfo, java.lang.String, org.apache.lucene.index.FieldInfos, org.apache.lucene.store.IOContext).
void	write(Directory directory, SegmentInfo segmentInfo, String segmentSuffix, FieldInfos infos, IOContext context)	Writes the provided FieldInfos to the directory.

Methods inherited from class java.lang.Object

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

Constructor Details

Lucene90FieldInfosFormat

public Lucene90FieldInfosFormat()

Sole constructor.

Method Details

read

public FieldInfos read(Directory directory,
 SegmentInfo segmentInfo,
 String segmentSuffix,
 IOContext context)
                throws IOException

Description copied from class: FieldInfosFormat

Read the FieldInfos previously written with FieldInfosFormat.write(org.apache.lucene.store.Directory, org.apache.lucene.index.SegmentInfo, java.lang.String, org.apache.lucene.index.FieldInfos, org.apache.lucene.store.IOContext).

Specified by:

read in class FieldInfosFormat

Throws:

IOException

write

public void write(Directory directory,
 SegmentInfo segmentInfo,
 String segmentSuffix,
 FieldInfos infos,
 IOContext context)
           throws IOException

Description copied from class: FieldInfosFormat

Writes the provided FieldInfos to the directory.

Specified by:

write in class FieldInfosFormat

Throws:

IOException