org.apache.lucene.index
Class SegmentInfos

java.lang.Object
  extended by java.util.AbstractCollection<E>
      extended by java.util.AbstractList<E>
          extended by java.util.Vector<SegmentInfo>
              extended by org.apache.lucene.index.SegmentInfos
All Implemented Interfaces:
Serializable, Cloneable, Iterable<SegmentInfo>, Collection<SegmentInfo>, List<SegmentInfo>, RandomAccess

public final class SegmentInfos
extends Vector<SegmentInfo>

A collection of segmentInfo objects with methods for operating on those segments in relation to the file system.

NOTE: This API is new and still experimental (subject to change suddenly in the next release)

See Also:
Serialized Form

Nested Class Summary
static class SegmentInfos.FindSegmentsFile
          Utility class for executing code that needs to do something with the current segments file.
 
Field Summary
 int counter
           
static int FORMAT
          The file format version, a negative number.
static int FORMAT_CHECKSUM
          This format adds a checksum at the end of the file to ensure all bytes were successfully written.
static int FORMAT_DEL_COUNT
          This format adds the deletion count for each segment.
static int FORMAT_DIAGNOSTICS
          This format adds optional per-segment String diagnostics storage, and switches userData to Map
static int FORMAT_HAS_PROX
          This format adds the boolean hasProx to record if any fields in the segment store prox information (ie, have omitTermFreqAndPositions==false)
static int FORMAT_LOCKLESS
          This format adds details used for lockless commits.
static int FORMAT_SHARED_DOC_STORE
          This format allows multiple segments to share a single vectors and stored fields file.
static int FORMAT_SINGLE_NORM_FILE
          This format adds a "hasSingleNormFile" flag into each segment info.
static int FORMAT_USER_DATA
          This format adds optional commit userData (String) storage.
 
Fields inherited from class java.util.Vector
capacityIncrement, elementCount, elementData
 
Fields inherited from class java.util.AbstractList
modCount
 
Constructor Summary
SegmentInfos()
           
 
Method Summary
 Object clone()
          Returns a copy of this instance, also copying each SegmentInfo.
 Collection<String> files(Directory dir, boolean includeSegmentsFile)
          Returns all file names referenced by SegmentInfo instances matching the provided Directory (ie files associated with any "external" segments are skipped).
static long generationFromSegmentsFileName(String fileName)
          Parse the generation off the segments file name and return it.
 String getCurrentSegmentFileName()
          Get the segments_N filename in use by this segment infos.
static String getCurrentSegmentFileName(Directory directory)
          Get the filename of the current segments_N file in the directory.
static String getCurrentSegmentFileName(String[] files)
          Get the filename of the current segments_N file from a list of files.
static long getCurrentSegmentGeneration(Directory directory)
          Get the generation (N) of the current segments_N file in the directory.
static long getCurrentSegmentGeneration(String[] files)
          Get the generation (N) of the current segments_N file from a list of files.
static int getDefaultGenFileRetryCount()
           
static int getDefaultGenFileRetryPauseMsec()
           
static int getDefaultGenLookahedCount()
           
 long getGeneration()
           
static PrintStream getInfoStream()
           
 long getLastGeneration()
           
 String getNextSegmentFileName()
          Get the next segments_N filename that will be written.
 Map<String,String> getUserData()
           
 long getVersion()
          version number when this SegmentInfos was generated.
 boolean hasExternalSegments(Directory dir)
           
 SegmentInfo info(int i)
           
 SegmentInfos range(int first, int last)
          Returns a new SegmentInfos containing the SegmentInfo instances in the specified range first (inclusive) to last (exclusive), so total number of segments returned is last-first.
 void read(Directory directory)
          This version of read uses the retry logic (for lock-less commits) to find the right segments file to load.
 void read(Directory directory, String segmentFileName)
          Read a particular segmentFileName.
static Map<String,String> readCurrentUserData(Directory directory)
          Returns userData from latest segments file
static long readCurrentVersion(Directory directory)
          Current version number from segments file.
 String segString(Directory directory)
           
static void setDefaultGenFileRetryCount(int count)
          Advanced: set how many times to try loading the segments.gen file contents to determine current segment generation.
static void setDefaultGenFileRetryPauseMsec(int msec)
          Advanced: set how many milliseconds to pause in between attempts to load the segments.gen file.
static void setDefaultGenLookaheadCount(int count)
          Advanced: set how many times to try incrementing the gen when loading the segments file.
static void setInfoStream(PrintStream infoStream)
          If non-null, information about retries when loading the segments file will be printed to this.
 
Methods inherited from class java.util.Vector
add, add, addAll, addAll, addElement, capacity, clear, contains, containsAll, copyInto, elementAt, elements, ensureCapacity, equals, firstElement, get, hashCode, indexOf, indexOf, insertElementAt, isEmpty, lastElement, lastIndexOf, lastIndexOf, remove, remove, removeAll, removeAllElements, removeElement, removeElementAt, removeRange, retainAll, set, setElementAt, setSize, size, subList, toArray, toArray, toString, trimToSize
 
Methods inherited from class java.util.AbstractList
iterator, listIterator, listIterator
 
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface java.util.List
iterator, listIterator, listIterator
 

Field Detail

FORMAT

public static final int FORMAT
The file format version, a negative number.

See Also:
Constant Field Values

FORMAT_LOCKLESS

public static final int FORMAT_LOCKLESS
This format adds details used for lockless commits. It differs slightly from the previous format in that file names are never re-used (write once). Instead, each file is written to the next generation. For example, segments_1, segments_2, etc. This allows us to not use a commit lock. See file formats for details.

See Also:
Constant Field Values

FORMAT_SINGLE_NORM_FILE

public static final int FORMAT_SINGLE_NORM_FILE
This format adds a "hasSingleNormFile" flag into each segment info. See LUCENE-756 for details.

See Also:
Constant Field Values

FORMAT_SHARED_DOC_STORE

public static final int FORMAT_SHARED_DOC_STORE
This format allows multiple segments to share a single vectors and stored fields file.

See Also:
Constant Field Values

FORMAT_CHECKSUM

public static final int FORMAT_CHECKSUM
This format adds a checksum at the end of the file to ensure all bytes were successfully written.

See Also:
Constant Field Values

FORMAT_DEL_COUNT

public static final int FORMAT_DEL_COUNT
This format adds the deletion count for each segment. This way IndexWriter can efficiently report numDocs().

See Also:
Constant Field Values

FORMAT_HAS_PROX

public static final int FORMAT_HAS_PROX
This format adds the boolean hasProx to record if any fields in the segment store prox information (ie, have omitTermFreqAndPositions==false)

See Also:
Constant Field Values

FORMAT_USER_DATA

public static final int FORMAT_USER_DATA
This format adds optional commit userData (String) storage.

See Also:
Constant Field Values

FORMAT_DIAGNOSTICS

public static final int FORMAT_DIAGNOSTICS
This format adds optional per-segment String diagnostics storage, and switches userData to Map

See Also:
Constant Field Values

counter

public int counter
Constructor Detail

SegmentInfos

public SegmentInfos()
Method Detail

info

public final SegmentInfo info(int i)

getCurrentSegmentGeneration

public static long getCurrentSegmentGeneration(String[] files)
Get the generation (N) of the current segments_N file from a list of files.

Parameters:
files - -- array of file names to check

getCurrentSegmentGeneration

public static long getCurrentSegmentGeneration(Directory directory)
                                        throws IOException
Get the generation (N) of the current segments_N file in the directory.

Parameters:
directory - -- directory to search for the latest segments_N file
Throws:
IOException

getCurrentSegmentFileName

public static String getCurrentSegmentFileName(String[] files)
                                        throws IOException
Get the filename of the current segments_N file from a list of files.

Parameters:
files - -- array of file names to check
Throws:
IOException

getCurrentSegmentFileName

public static String getCurrentSegmentFileName(Directory directory)
                                        throws IOException
Get the filename of the current segments_N file in the directory.

Parameters:
directory - -- directory to search for the latest segments_N file
Throws:
IOException

getCurrentSegmentFileName

public String getCurrentSegmentFileName()
Get the segments_N filename in use by this segment infos.


generationFromSegmentsFileName

public static long generationFromSegmentsFileName(String fileName)
Parse the generation off the segments file name and return it.


getNextSegmentFileName

public String getNextSegmentFileName()
Get the next segments_N filename that will be written.


read

public final void read(Directory directory,
                       String segmentFileName)
                throws CorruptIndexException,
                       IOException
Read a particular segmentFileName. Note that this may throw an IOException if a commit is in process.

Parameters:
directory - -- directory containing the segments file
segmentFileName - -- segment file to load
Throws:
CorruptIndexException - if the index is corrupt
IOException - if there is a low-level IO error

read

public final void read(Directory directory)
                throws CorruptIndexException,
                       IOException
This version of read uses the retry logic (for lock-less commits) to find the right segments file to load.

Throws:
CorruptIndexException - if the index is corrupt
IOException - if there is a low-level IO error

clone

public Object clone()
Returns a copy of this instance, also copying each SegmentInfo.

Overrides:
clone in class Vector<SegmentInfo>

getVersion

public long getVersion()
version number when this SegmentInfos was generated.


getGeneration

public long getGeneration()

getLastGeneration

public long getLastGeneration()

readCurrentVersion

public static long readCurrentVersion(Directory directory)
                               throws CorruptIndexException,
                                      IOException
Current version number from segments file.

Throws:
CorruptIndexException - if the index is corrupt
IOException - if there is a low-level IO error

readCurrentUserData

public static Map<String,String> readCurrentUserData(Directory directory)
                                              throws CorruptIndexException,
                                                     IOException
Returns userData from latest segments file

Throws:
CorruptIndexException - if the index is corrupt
IOException - if there is a low-level IO error

setInfoStream

public static void setInfoStream(PrintStream infoStream)
If non-null, information about retries when loading the segments file will be printed to this.


setDefaultGenFileRetryCount

public static void setDefaultGenFileRetryCount(int count)
Advanced: set how many times to try loading the segments.gen file contents to determine current segment generation. This file is only referenced when the primary method (listing the directory) fails.


getDefaultGenFileRetryCount

public static int getDefaultGenFileRetryCount()
See Also:
setDefaultGenFileRetryCount(int)

setDefaultGenFileRetryPauseMsec

public static void setDefaultGenFileRetryPauseMsec(int msec)
Advanced: set how many milliseconds to pause in between attempts to load the segments.gen file.


getDefaultGenFileRetryPauseMsec

public static int getDefaultGenFileRetryPauseMsec()
See Also:
setDefaultGenFileRetryPauseMsec(int)

setDefaultGenLookaheadCount

public static void setDefaultGenLookaheadCount(int count)
Advanced: set how many times to try incrementing the gen when loading the segments file. This only runs if the primary (listing directory) and secondary (opening segments.gen file) methods fail to find the segments file.


getDefaultGenLookahedCount

public static int getDefaultGenLookahedCount()
See Also:
setDefaultGenLookaheadCount(int)

getInfoStream

public static PrintStream getInfoStream()
See Also:
setInfoStream(java.io.PrintStream)

range

public SegmentInfos range(int first,
                          int last)
Returns a new SegmentInfos containing the SegmentInfo instances in the specified range first (inclusive) to last (exclusive), so total number of segments returned is last-first.


files

public Collection<String> files(Directory dir,
                                boolean includeSegmentsFile)
                         throws IOException
Returns all file names referenced by SegmentInfo instances matching the provided Directory (ie files associated with any "external" segments are skipped). The returned collection is recomputed on each invocation.

Throws:
IOException

segString

public String segString(Directory directory)

getUserData

public Map<String,String> getUserData()

hasExternalSegments

public boolean hasExternalSegments(Directory dir)


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