Package org.apache.lucene.index
Class IndexFileNames
- java.lang.Object
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- org.apache.lucene.index.IndexFileNames
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public final class IndexFileNames extends 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.
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Field Summary
Fields Modifier and Type Field Description static Pattern
CODEC_FILE_PATTERN
All files created by codecs much match this pattern (checked in SegmentInfo).static String
COMPOUND_FILE_ENTRIES_EXTENSION
Extension of compound file entriesstatic String
COMPOUND_FILE_EXTENSION
Extension of compound filestatic String
GEN_EXTENSION
Extension of gen filestatic 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 String
SEGMENTS
Name of the index segment filestatic String
SEGMENTS_GEN
Name of the generation reference file name
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static String
fileNameFromGeneration(String base, String ext, long gen)
Computes the full file name from base, extension and generation.static boolean
matchesExtension(String filename, String ext)
Returns true if the given filename ends with the given extension.static String
parseSegmentName(String filename)
Parses the segment name out of the given file name.static String
segmentFileName(String segmentName, String segmentSuffix, String ext)
Returns a file name that includes the given segment name, your own custom name and extension.static String
stripExtension(String filename)
Removes the extension (anything after the first '.'), otherwise returns the original filename.static String
stripSegmentName(String filename)
Strips the segment name out of the given file name.
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Field Detail
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SEGMENTS
public static final String SEGMENTS
Name of the index segment file- See Also:
- Constant Field Values
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GEN_EXTENSION
public static final String GEN_EXTENSION
Extension of gen file- See Also:
- Constant Field Values
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SEGMENTS_GEN
public static final String SEGMENTS_GEN
Name of the generation reference file name- See Also:
- Constant Field Values
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COMPOUND_FILE_EXTENSION
public static final String COMPOUND_FILE_EXTENSION
Extension of compound file- See Also:
- Constant Field Values
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COMPOUND_FILE_ENTRIES_EXTENSION
public static final String COMPOUND_FILE_ENTRIES_EXTENSION
Extension of compound file entries- See Also:
- Constant Field Values
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INDEX_EXTENSIONS
public static final 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'ssegments_N
files do not have any filename extension.
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CODEC_FILE_PATTERN
public static final Pattern CODEC_FILE_PATTERN
All files created by codecs much match this pattern (checked in SegmentInfo).
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Method Detail
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fileNameFromGeneration
public static String fileNameFromGeneration(String base, 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 ifext
is not an empty string.- Parameters:
base
- main part of the file nameext
- extension of the filenamegen
- generation
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segmentFileName
public static String segmentFileName(String segmentName, String segmentSuffix, 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).
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matchesExtension
public static boolean matchesExtension(String filename, String ext)
Returns true if the given filename ends with the given extension. One should provide a pure extension, without '.'.
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stripSegmentName
public static String stripSegmentName(String filename)
Strips the segment name out of the given file name. If you usedsegmentFileName(java.lang.String, java.lang.String, java.lang.String)
orfileNameFromGeneration(java.lang.String, java.lang.String, long)
to create your files, then this method simply removes whatever comes before the first '.', or the second '_' (excluding both).- Returns:
- the filename with the segment name removed, or the given filename if it does not contain a '.' and '_'.
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parseSegmentName
public static String parseSegmentName(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 '_'.
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