Package org.apache.lucene.index

Class IndexFileNames

  • public final class IndexFileNames
extends java.lang.Object
    This class contains useful constants representing filenames and extensions used by lucene, as well as convenience methods for querying whether a file name matches an extension (matchesExtension), as well as generating file names from a segment name, generation and extension ( fileNameFromGeneration, segmentFileName).

    NOTE: extensions used by codecs are not listed here. You must interact with the Codec directly.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static java.util.regex.Pattern CODEC_FILE_PATTERN
      All files created by codecs much match this pattern (checked in SegmentInfo).
      static java.lang.String COMPOUND_FILE_ENTRIES_EXTENSION
      Extension of compound file entries
      static java.lang.String COMPOUND_FILE_EXTENSION
      Extension of compound file
      static java.lang.String GEN_EXTENSION
      Extension of gen file
      static java.lang.String[] INDEX_EXTENSIONS
      This array contains all filename extensions used by Lucene's index files, with one exception, namely the extension made up from .s + a number.
      static java.lang.String SEGMENTS
      Name of the index segment file
      static java.lang.String SEGMENTS_GEN
      Name of the generation reference file name

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static java.lang.String fileNameFromGeneration​(java.lang.String base, java.lang.String ext, long gen)
      Computes the full file name from base, extension and generation.
      static boolean matchesExtension​(java.lang.String filename, java.lang.String ext)
      Returns true if the given filename ends with the given extension.
      static java.lang.String parseSegmentName​(java.lang.String filename)
      Parses the segment name out of the given file name.
      static java.lang.String segmentFileName​(java.lang.String segmentName, java.lang.String segmentSuffix, java.lang.String ext)
      Returns a file name that includes the given segment name, your own custom name and extension.
      static java.lang.String stripExtension​(java.lang.String filename)
      Removes the extension (anything after the first '.'), otherwise returns the original filename.
      static java.lang.String stripSegmentName​(java.lang.String filename)
      Strips the segment name out of the given file name.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • SEGMENTS

        public static final java.lang.String SEGMENTS
        Name of the index segment file
        See Also:
        Constant Field Values

      • GEN_EXTENSION

        public static final java.lang.String GEN_EXTENSION
        Extension of gen file
        See Also:
        Constant Field Values

      • SEGMENTS_GEN

        public static final java.lang.String SEGMENTS_GEN
        Name of the generation reference file name
        See Also:
        Constant Field Values

      • COMPOUND_FILE_EXTENSION

        public static final java.lang.String COMPOUND_FILE_EXTENSION
        Extension of compound file
        See Also:
        Constant Field Values

      • COMPOUND_FILE_ENTRIES_EXTENSION

        public static final java.lang.String COMPOUND_FILE_ENTRIES_EXTENSION
        Extension of compound file entries
        See Also:
        Constant Field Values

      • INDEX_EXTENSIONS

        public static final java.lang.String[] INDEX_EXTENSIONS
        This array contains all filename extensions used by Lucene's index files, with one exception, namely the extension made up from .s + a number. Also note that Lucene's segments_N files do not have any filename extension.

      • CODEC_FILE_PATTERN

        public static final java.util.regex.Pattern CODEC_FILE_PATTERN
        All files created by codecs much match this pattern (checked in SegmentInfo).

    • Method Detail

      • fileNameFromGeneration

        public static java.lang.String fileNameFromGeneration​(java.lang.String base,
                                                      java.lang.String ext,
                                                      long gen)
        Computes the full file name from base, extension and generation. If the generation is -1, the file name is null. If it's 0, the file name is <base>.<ext>. If it's > 0, the file name is <base>_<gen>.<ext>.
        NOTE: .<ext> is added to the name only if ext is not an empty string.
        Parameters:
        base - main part of the file name
        ext - extension of the filename
        gen - generation

      • segmentFileName

        public static java.lang.String segmentFileName​(java.lang.String segmentName,
                                               java.lang.String segmentSuffix,
                                               java.lang.String ext)
        Returns a file name that includes the given segment name, your own custom name and extension. The format of the filename is: <segmentName>(_<name>)(.<ext>).

        NOTE: .<ext> is added to the result file name only if ext is not empty.

        NOTE: _<segmentSuffix> is added to the result file name only if it's not the empty string

        NOTE: all custom files should be named using this method, or otherwise some structures may fail to handle them properly (such as if they are added to compound files).

      • matchesExtension

        public static boolean matchesExtension​(java.lang.String filename,
                                       java.lang.String ext)
        Returns true if the given filename ends with the given extension. One should provide a pure extension, without '.'.

      • parseSegmentName

        public static java.lang.String parseSegmentName​(java.lang.String filename)
        Parses the segment name out of the given file name.
        Returns:
        the segment name only, or filename if it does not contain a '.' and '_'.

      • stripExtension

        public static java.lang.String stripExtension​(java.lang.String filename)
        Removes the extension (anything after the first '.'), otherwise returns the original filename.