Class Lucene40FieldInfosFormat

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:

• Header --> CodecHeader (WriteHeader(DataOutput, string, int))
• FieldsCount --> VInt (WriteVInt32(int))
• FieldName --> String (WriteString(string))
• FieldBits, DocValuesBits --> Byte (WriteByte(byte))
• FieldNumber --> VInt (WriteInt32(int))
• Attributes --> IDictionary<String,String> (WriteStringStringMap(IDictionary<string, string>))

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. (VAR_INTS)
  • 2: 32-bit floating point values. (FLOAT_32)
  • 3: 64-bit floating point values. (FLOAT_64)
  • 4: fixed-length byte array values. (BYTES_FIXED_STRAIGHT)
  • 5: fixed-length dereferenced byte array values. (BYTES_FIXED_DEREF)
  • 6: variable-length byte array values. (BYTES_VAR_STRAIGHT)
  • 7: variable-length dereferenced byte array values. (BYTES_VAR_DEREF)
  • 8: 16-bit signed integers. (FIXED_INTS_16)
  • 9: 32-bit signed integers. (FIXED_INTS_32)
  • 10: 64-bit signed integers. (FIXED_INTS_64)
  • 11: 8-bit signed integers. (FIXED_INTS_8)
  • 12: fixed-length sorted byte array values. (BYTES_FIXED_SORTED)
  • 13: variable-length sorted byte array values. (BYTES_VAR_SORTED)
• Attributes: a key-value map of codec-private attributes.

Note

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

Inheritance

object

FieldInfosFormat

Lucene40FieldInfosFormat

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Lucene.Net.Codecs.Lucene40

Assembly: Lucene.Net.dll

Syntax

[Obsolete("Only for reading old 4.0 and 4.1 segments")]
public class Lucene40FieldInfosFormat : FieldInfosFormat

Constructors

Lucene40FieldInfosFormat()

Sole constructor.

Declaration

public Lucene40FieldInfosFormat()

Properties

FieldInfosReader

Returns a FieldInfosReader to read field infos from the index.

Declaration

public override FieldInfosReader FieldInfosReader { get; }

Property Value

Type	Description
FieldInfosReader

Overrides

FieldInfosFormat.FieldInfosReader

FieldInfosWriter

Returns a FieldInfosWriter to write field infos to the index.

Declaration

public override FieldInfosWriter FieldInfosWriter { get; }

Property Value

Type	Description
FieldInfosWriter

Overrides

FieldInfosFormat.FieldInfosWriter