Package org.apache.lucene.codecs.lucene40

Class Lucene40FieldInfosFormat

java.lang.Object
org.apache.lucene.codecs.FieldInfosFormat
org.apache.lucene.codecs.lucene40.Lucene40FieldInfosFormat
@Deprecated public class Lucene40FieldInfosFormat extends FieldInfosFormat
Deprecated.
Only for reading old 4.0 and 4.1 segments
Lucene 4.0 Field Infos format.

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

FieldInfos (.fnm) --> Header,FieldsCount, <FieldName,FieldNumber, FieldBits,DocValuesBits,Attributes> FieldsCount

Data types:

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 is one for indexed fields, and zero for non-indexed fields.
    • The second lowest-order bit is one for fields that have term vectors stored, and zero for fields without term vectors.
    • If the third lowest order-bit is set (0x4), offsets are stored into the postings list in addition to positions.
    • Fourth bit is unused.
    • If the fifth lowest-order bit is set (0x10), norms are omitted for the indexed field.
    • If the sixth lowest-order bit is set (0x20), payloads are stored for the indexed field.
    • If the seventh lowest-order bit is set (0x40), term frequencies and positions omitted for the indexed field.
    • If the eighth lowest-order bit is set (0x80), positions are omitted for the indexed field.
  • 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: variable-width signed integers. (Type#VAR_INTS VAR_INTS)
    • 2: 32-bit floating point values. (Type#FLOAT_32 FLOAT_32)
    • 3: 64-bit floating point values. (Type#FLOAT_64 FLOAT_64)
    • 4: fixed-length byte array values. (Type#BYTES_FIXED_STRAIGHT BYTES_FIXED_STRAIGHT)
    • 5: fixed-length dereferenced byte array values. (Type#BYTES_FIXED_DEREF BYTES_FIXED_DEREF)
    • 6: variable-length byte array values. (Type#BYTES_VAR_STRAIGHT BYTES_VAR_STRAIGHT)
    • 7: variable-length dereferenced byte array values. (Type#BYTES_VAR_DEREF BYTES_VAR_DEREF)
    • 8: 16-bit signed integers. (Type#FIXED_INTS_16 FIXED_INTS_16)
    • 9: 32-bit signed integers. (Type#FIXED_INTS_32 FIXED_INTS_32)
    • 10: 64-bit signed integers. (Type#FIXED_INTS_64 FIXED_INTS_64)
    • 11: 8-bit signed integers. (Type#FIXED_INTS_8 FIXED_INTS_8)
    • 12: fixed-length sorted byte array values. (Type#BYTES_FIXED_SORTED BYTES_FIXED_SORTED)
    • 13: variable-length sorted byte array values. (Type#BYTES_VAR_SORTED BYTES_VAR_SORTED)
  • Attributes: a key-value map of codec-private attributes.