Package org.apache.lucene.codecs.lucene90

Class Lucene90CompoundFormat

java.lang.Object

org.apache.lucene.codecs.CompoundFormat

org.apache.lucene.codecs.lucene90.Lucene90CompoundFormat

public final class Lucene90CompoundFormat
extends CompoundFormat

Lucene 9.0 compound file format

Files:

• .cfs: An optional "virtual" file consisting of all the other index files for systems that frequently run out of file handles.
• .cfe: The "virtual" compound file's entry table holding all entries in the corresponding .cfs file.

Description:

• Compound (.cfs) --> Header, FileData ^FileCount, Footer
• Compound Entry Table (.cfe) --> Header, FileCount, <FileName, DataOffset, DataLength> ^FileCount
• Header --> IndexHeader
• FileCount --> VInt
• DataOffset,DataLength,Checksum --> UInt64
• FileName --> String
• FileData --> raw file data
• Footer --> CodecFooter

Notes:

• FileCount indicates how many files are contained in this compound file. The entry table that follows has that many entries.
• Each directory entry contains a long pointer to the start of this file's data section, the files length, and a String with that file's name. The start of file's data section is aligned to 8 bytes to not introduce additional unaligned accesses with mmap.

Constructor Summary

Constructors

Constructor	Description
Lucene90CompoundFormat()	Sole constructor.

Method Summary

Modifier and Type	Method	Description
CompoundDirectory	getCompoundReader(Directory dir, SegmentInfo si, IOContext context)	Returns a Directory view (read-only) for the compound files in this segment
void	write(Directory dir, SegmentInfo si, IOContext context)	Packs the provided segment's files into a compound format.

Methods inherited from class java.lang.Object

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

Constructor Detail

Lucene90CompoundFormat

public Lucene90CompoundFormat()

Sole constructor.

Method Detail

getCompoundReader

public CompoundDirectory getCompoundReader(Directory dir,
                                           SegmentInfo si,
                                           IOContext context)
                                    throws IOException

Description copied from class: CompoundFormat

Returns a Directory view (read-only) for the compound files in this segment

Specified by:

getCompoundReader in class CompoundFormat

Throws:

IOException

write

public void write(Directory dir,
                  SegmentInfo si,
                  IOContext context)
           throws IOException

Description copied from class: CompoundFormat

Packs the provided segment's files into a compound format. All files referenced by the provided SegmentInfo must have CodecUtil.writeIndexHeader(org.apache.lucene.store.DataOutput, java.lang.String, int, byte[], java.lang.String) and CodecUtil.writeFooter(org.apache.lucene.store.IndexOutput).

Specified by:

write in class CompoundFormat

Throws:

IOException