Module org.apache.lucene.codecs

Package org.apache.lucene.codecs.simpletext

Class SimpleTextDocValuesFormat

java.lang.Object

org.apache.lucene.codecs.DocValuesFormat

org.apache.lucene.codecs.simpletext.SimpleTextDocValuesFormat

All Implemented Interfaces:

NamedSPILoader.NamedSPI

class SimpleTextDocValuesFormat
extends DocValuesFormat

plain text doc values format.

FOR RECREATIONAL USE ONLY

the .dat file contains the data. for numbers this is a "fixed-width" file, for example a single byte range:

  field myField
    type NUMERIC
    minvalue 0
    pattern 000
  005
  T
  234
  T
  123
  T
  ...
  

so a document's value (delta encoded from minvalue) can be retrieved by seeking to startOffset + (1+pattern.length()+2)*docid. The extra 1 is the newline. The extra 2 is another newline and 'T' or 'F': true if the value is real, false if missing.

for bytes this is also a "fixed-width" file, for example:

  field myField
    type BINARY
    maxlength 6
    pattern 0
  length 6
  foobar[space][space]
  T
  length 3
  baz[space][space][space][space][space]
  T
  ...
  

so a doc's value can be retrieved by seeking to startOffset + (9+pattern.length+maxlength+2)*doc the extra 9 is 2 newlines, plus "length " itself. the extra 2 is another newline and 'T' or 'F': true if the value is real, false if missing.

for sorted bytes this is a fixed-width file, for example:

  field myField
    type SORTED
    numvalues 10
    maxLength 8
    pattern 0
    ordpattern 00
  length 6
  foobar[space][space]
  length 3
  baz[space][space][space][space][space]
  ...
  03
  06
  01
  10
  ...
  

so the "ord section" begins at startOffset + (9+pattern.length+maxlength)*numValues. a document's ord can be retrieved by seeking to "ord section" + (1+ordpattern.length())*docid an ord's value can be retrieved by seeking to startOffset + (9+pattern.length+maxlength)*ord

for sorted set this is a fixed-width file very similar to the SORTED case, for example:

  field myField
    type SORTED_SET
    numvalues 10
    maxLength 8
    pattern 0
    ordpattern XXXXX
  length 6
  foobar[space][space]
  length 3
  baz[space][space][space][space][space]
  ...
  0,3,5
  1,2

  10
  ...
  

so the "ord section" begins at startOffset + (9+pattern.length+maxlength)*numValues. a document's ord list can be retrieved by seeking to "ord section" + (1+ordpattern.length())*docid this is a comma-separated list, and it's padded with spaces to be fixed width. so trim() and split() it. and beware the empty string! an ord's value can be retrieved by seeking to startOffset + (9+pattern.length+maxlength)*ord

for sorted numerics, it's encoded (not very creatively) as a comma-separated list of strings the same as binary. beware the empty string!

the reader can just scan this file when it opens, skipping over the data blocks and saving the offset/etc for each field.

Constructor Summary

Constructors

Constructor	Description
SimpleTextDocValuesFormat()

Method Summary

Modifier and Type	Method	Description
DocValuesConsumer	fieldsConsumer(SegmentWriteState state)	Returns a DocValuesConsumer to write docvalues to the index.
DocValuesProducer	fieldsProducer(SegmentReadState state)	Returns a DocValuesProducer to read docvalues from the index.

Methods inherited from class org.apache.lucene.codecs.DocValuesFormat

availableDocValuesFormats, forName, getName, reloadDocValuesFormats, toString

Methods inherited from class java.lang.Object

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

Constructor Details

SimpleTextDocValuesFormat

public SimpleTextDocValuesFormat()

Method Details

fieldsConsumer

public DocValuesConsumer fieldsConsumer(SegmentWriteState state)
                                 throws IOException

Description copied from class: DocValuesFormat

Returns a DocValuesConsumer to write docvalues to the index.

Specified by:

fieldsConsumer in class DocValuesFormat

Throws:

IOException

fieldsProducer

public DocValuesProducer fieldsProducer(SegmentReadState state)
                                 throws IOException

Description copied from class: DocValuesFormat

Returns a DocValuesProducer to read docvalues from the index.

NOTE: by the time this call returns, it must hold open any files it will need to use; else, those files may be deleted. Additionally, required files may be deleted during the execution of this call before there is a chance to open them. Under these circumstances an IOException should be thrown by the implementation. IOExceptions are expected and will automatically cause a retry of the segment opening logic with the newly revised segments.

Specified by:

fieldsProducer in class DocValuesFormat

Throws:

IOException