Class Lucene90CompoundFormat

  • public final class Lucene90CompoundFormat
    extends CompoundFormat
    Lucene 9.0 compound file format


    • .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.


    • 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


    • 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.