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 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.
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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
PENDING_SEGMENTS
Name of pending index segment filestatic java.lang.String
SEGMENTS
Name of the index segment file
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Constructor Summary
Constructors Modifier Constructor Description private
IndexFileNames()
No instance
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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 java.lang.String
getExtension(java.lang.String filename)
Return the extension (anything after the first '.'), or null if there is no '.' in the file name.private static int
indexOfSegmentName(java.lang.String filename)
locates the boundary of the segment name, or -1static boolean
matchesExtension(java.lang.String filename, java.lang.String ext)
Returns true if the given filename ends with the given extension.static long
parseGeneration(java.lang.String filename)
Returns the generation from this file name, or 0 if there is no generation.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.
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Field Detail
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SEGMENTS
public static final java.lang.String SEGMENTS
Name of the index segment file- See Also:
- Constant Field Values
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PENDING_SEGMENTS
public static final java.lang.String PENDING_SEGMENTS
Name of pending index segment file- See Also:
- Constant Field Values
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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).
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Method Detail
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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 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 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).
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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 '.'.
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indexOfSegmentName
private static int indexOfSegmentName(java.lang.String filename)
locates the boundary of the segment name, or -1
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stripSegmentName
public static java.lang.String stripSegmentName(java.lang.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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parseGeneration
public static long parseGeneration(java.lang.String filename)
Returns the generation from this file name, or 0 if there is no generation.
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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 '_'.
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stripExtension
public static java.lang.String stripExtension(java.lang.String filename)
Removes the extension (anything after the first '.'), otherwise returns the original filename.
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getExtension
public static java.lang.String getExtension(java.lang.String filename)
Return the extension (anything after the first '.'), or null if there is no '.' in the file name.
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