SegmentInfos (Lucene 3.6.0 API)

java.lang.Object
- org.apache.lucene.index.SegmentInfos

All Implemented Interfaces:

Cloneable, Iterable<SegmentInfo>
```
public final class SegmentInfos
extends Object
implements Cloneable, Iterable<SegmentInfo>
```
A collection of segmentInfo objects with methods for operating on those segments in relation to the file system.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`SegmentInfos.FindSegmentsFile` Utility class for executing code that needs to do something with the current segments file.

Field Summary

Fields
Modifier and Type	Field and Description
`int`	`counter`
`static int`	`CURRENT_FORMAT`
`static int`	`FORMAT` The file format version, a negative number.
`static int`	`FORMAT_3_1` Each segment records the Lucene version that created it.
`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_HAS_VECTORS` Each segment records whether it has term vectors
`static int`	`FORMAT_LOCKLESS` This format adds details used for lockless commits.
`static int`	`FORMAT_MAXIMUM`
`static int`	`FORMAT_MINIMUM`
`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.

Constructor Summary

Constructors
Constructor and Description

SegmentInfos()

Constructors
Constructor and Description
`SegmentInfos()`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`add(SegmentInfo si)`
`void`	`addAll(Iterable<SegmentInfo> sis)`
`List<SegmentInfo>`	`asList()` Returns all contained segments as an unmodifiable `List` view.
`Set<SegmentInfo>`	`asSet()` Returns all contained segments as an unmodifiable `Set` view.
`void`	`changed()` Call this before committing if changes have been made to the segments.
`void`	`clear()`
`Object`	`clone()` Returns a copy of this instance, also copying each SegmentInfo.
`boolean`	`contains(SegmentInfo si)`
`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.
`static int`	`getDefaultGenLookahedCount()`
`int`	`getFormat()`
`long`	`getGeneration()`
`static PrintStream`	`getInfoStream()`
`static long`	`getLastCommitGeneration(Directory directory)` Get the generation of the most recent commit to the index in this directory (N in the segments_N file).
`static long`	`getLastCommitGeneration(String[] files)` Get the generation of the most recent commit to the list of index files (N in the segments_N file).
`static String`	`getLastCommitSegmentsFileName(Directory directory)` Get the filename of the segments_N file for the most recent commit to the index in this Directory.
`static String`	`getLastCommitSegmentsFileName(String[] files)` Get the filename of the segments_N file for the most recent commit in the list of index files.
`long`	`getLastGeneration()`
`String`	`getNextSegmentFileName()` Get the next segments_N filename that will be written.
`String`	`getSegmentsFileName()` Get the segments_N filename in use by this segment infos.
`Map<String,String>`	`getUserData()`
`long`	`getVersion()` version number when this SegmentInfos was generated.
`int`	`indexOf(SegmentInfo si)`
`SegmentInfo`	`info(int i)`
`Iterator<SegmentInfo>`	`iterator()` Returns an unmodifiable `Iterator` of contained segments in order.
`void`	`pruneDeletedSegments()` Prunes any segment whose docs are all deleted.
`SegmentInfos`	`range(int first, int last)` Deprecated. use `asList().subList(first, last)` instead.
`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 long`	`readCurrentVersion(Directory directory)` Deprecated. Load the SegmentInfos and then call `getVersion()`.
`void`	`remove(int index)`
`void`	`remove(SegmentInfo si)`
`static void`	`setDefaultGenLookaheadCount(int count)` Advanced: set how many times to try incrementing the gen when loading the segments file.
`void`	`setFormat(int format)`
`static void`	`setInfoStream(PrintStream infoStream)` If non-null, information about retries when loading the segments file will be printed to this.
`int`	`size()`
`String`	`toString(Directory directory)`
`int`	`totalDocCount()` Returns sum of all segment's docCounts.

Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 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
  - FORMAT_HAS_VECTORS
```
public static final int FORMAT_HAS_VECTORS
```
    Each segment records whether it has term vectors
    
    See Also:
    Constant Field Values
  - FORMAT_3_1
```
public static final int FORMAT_3_1
```
    Each segment records the Lucene version that created it.
    
    See Also:
    Constant Field Values
  - CURRENT_FORMAT
```
public static final int CURRENT_FORMAT
```
    See Also:
    Constant Field Values
  - FORMAT_MINIMUM
```
public static final int FORMAT_MINIMUM
```
    See Also:
    Constant Field Values
  - FORMAT_MAXIMUM
```
public static final int FORMAT_MAXIMUM
```
    See Also:
    Constant Field Values
  - counter
```
public int counter
```
- Constructor Detail
  - SegmentInfos
```
public SegmentInfos()
```
- Method Detail
  - setFormat
```
public void setFormat(int format)
```
  - getFormat
```
public int getFormat()
```
  - info
```
public SegmentInfo info(int i)
```
  - getLastCommitGeneration
```
public static long getLastCommitGeneration(String[] files)
```
    Get the generation of the most recent commit to the list of index files (N in the segments_N file).
    
    Parameters:
    files - -- array of file names to check
  - getLastCommitGeneration
```
public static long getLastCommitGeneration(Directory directory)
                                    throws IOException
```
    Get the generation of the most recent commit to the index in this directory (N in the segments_N file).
    
    Parameters:
    directory - -- directory to search for the latest segments_N file
    
    Throws:
    
    IOException
  - getLastCommitSegmentsFileName
```
public static String getLastCommitSegmentsFileName(String[] files)
                                            throws IOException
```
    Get the filename of the segments_N file for the most recent commit in the list of index files.
    
    Parameters:
    files - -- array of file names to check
    
    Throws:
    
    IOException
  - getLastCommitSegmentsFileName
```
public static String getLastCommitSegmentsFileName(Directory directory)
                                            throws IOException
```
    Get the filename of the segments_N file for the most recent commit to the index in this Directory.
    
    Parameters:
    directory - -- directory to search for the latest segments_N file
    
    Throws:
    
    IOException
  - getSegmentsFileName
```
public String getSegmentsFileName()
```
    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
  - pruneDeletedSegments
```
public void pruneDeletedSegments()
                          throws IOException
```
    Prunes any segment whose docs are all deleted.
    
    Throws:
    
    IOException
  - clone
```
public Object clone()
```
    Returns a copy of this instance, also copying each SegmentInfo.
    
    Overrides:
    
    clone in class Object
  - getVersion
```
public long getVersion()
```
    version number when this SegmentInfos was generated.
  - getGeneration
```
public long getGeneration()
```
  - getLastGeneration
```
public long getLastGeneration()
```
  - readCurrentVersion
```
@Deprecated
public static long readCurrentVersion(Directory directory)
                               throws CorruptIndexException,
                                      IOException
```
    Deprecated. Load the SegmentInfos and then call getVersion().
    
    Current version number from 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.
  - 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.
    
    WARNING: This API is experimental and might change in incompatible ways in the next release.
  - getDefaultGenLookahedCount
```
public static int getDefaultGenLookahedCount()
```
    See Also:
    setDefaultGenLookaheadCount(int)
    WARNING: This API is experimental and might change in incompatible ways in the next release.
  - getInfoStream
```
public static PrintStream getInfoStream()
```
    See Also:
    setInfoStream(java.io.PrintStream)
  - range
```
@Deprecated
public SegmentInfos range(int first,
                            int last)
```
    Deprecated. use asList().subList(first, last) instead.
    
    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
  - toString
```
public String toString(Directory directory)
```
  - getUserData
```
public Map<String,String> getUserData()
```
  - totalDocCount
```
public int totalDocCount()
```
    Returns sum of all segment's docCounts. Note that this does not include deletions
  - changed
```
public void changed()
```
    Call this before committing if changes have been made to the segments.
  - iterator
```
public Iterator<SegmentInfo> iterator()
```
    Returns an unmodifiable Iterator of contained segments in order.
    
    Specified by:
    
    iterator in interface Iterable<SegmentInfo>
  - asList
```
public List<SegmentInfo> asList()
```
    Returns all contained segments as an unmodifiable List view.
  - asSet
```
public Set<SegmentInfo> asSet()
```
    Returns all contained segments as an unmodifiable Set view. The iterator is not sorted, use List view or iterator() to get all segments in order.
  - size
```
public int size()
```
  - add
```
public void add(SegmentInfo si)
```
  - addAll
```
public void addAll(Iterable<SegmentInfo> sis)
```
  - clear
```
public void clear()
```
  - remove
```
public void remove(SegmentInfo si)
```
  - remove
```
public void remove(int index)
```
  - contains
```
public boolean contains(SegmentInfo si)
```
  - indexOf
```
public int indexOf(SegmentInfo si)
```

Class SegmentInfos

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

FORMAT

FORMAT_LOCKLESS

FORMAT_SINGLE_NORM_FILE

FORMAT_SHARED_DOC_STORE

FORMAT_CHECKSUM

FORMAT_DEL_COUNT

FORMAT_HAS_PROX

FORMAT_USER_DATA

FORMAT_DIAGNOSTICS

FORMAT_HAS_VECTORS

FORMAT_3_1

CURRENT_FORMAT

FORMAT_MINIMUM

FORMAT_MAXIMUM

counter

Constructor Detail

SegmentInfos

Method Detail

setFormat

getFormat

info

getLastCommitGeneration

getLastCommitGeneration

getLastCommitSegmentsFileName

getLastCommitSegmentsFileName

getSegmentsFileName

generationFromSegmentsFileName

getNextSegmentFileName

read

read

pruneDeletedSegments

clone

getVersion

getGeneration

getLastGeneration

readCurrentVersion

setInfoStream

setDefaultGenLookaheadCount

getDefaultGenLookahedCount

getInfoStream

range

files

toString

getUserData

totalDocCount

changed

iterator

asList

asSet

size

add

addAll

clear

remove

remove

contains

indexOf