org.apache.lucene.index

Class SegmentInfo

java.lang.Object

org.apache.lucene.index.SegmentInfo

public final class SegmentInfo
extends Object

Information about a segment such as its name, directory, and files related to the segment.

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

Field Summary

Fields

Modifier and Type	Field and Description
Directory	dir Where this segment resides.
String	name Unique segment name in the directory.
static int	NO Used by some member fields to mean not present (e.g., norms, deletions).
static int	YES Used by some member fields to mean present (e.g., norms, deletions).

Constructor Summary

Constructors

Constructor and Description
SegmentInfo(Directory dir, Version version, Version minVersion, String name, int maxDoc, boolean isCompoundFile, Codec codec, Map<String,String> diagnostics, byte[] id, Map<String,String> attributes, Sort indexSort) Construct a new complete SegmentInfo instance from input.

Method Summary

Modifier and Type	Method and Description
void	addFile(String file) Add this file to the set of files written for this segment.
void	addFiles(Collection<String> files) Add these files to the set of files written for this segment.
boolean	equals(Object obj) We consider another SegmentInfo instance equal if it has the same dir and same name.
Set<String>	files() Return all files referenced by this SegmentInfo.
String	getAttribute(String key) Get a codec attribute value, or null if it does not exist
Map<String,String>	getAttributes() Returns the internal codec attributes map.
Codec	getCodec() Return Codec that wrote this segment.
Map<String,String>	getDiagnostics() Returns diagnostics saved into the segment when it was written.
byte[]	getId() Return the id that uniquely identifies this segment.
Sort	getIndexSort() Return the sort order of this segment, or null if the index has no sort.
Version	getMinVersion() Return the minimum Lucene version that contributed documents to this segment, or null if it is unknown.
boolean	getUseCompoundFile() Returns true if this segment is stored as a compound file; else, false.
Version	getVersion() Returns the version of the code which wrote the segment.
int	hashCode()
int	maxDoc() Returns number of documents in this segment (deletions are not taken into account).
String	putAttribute(String key, String value) Puts a codec attribute value.
void	setCodec(Codec codec) Can only be called once.
void	setFiles(Collection<String> files) Sets the files written for this segment.
String	toString()
String	toString(int delCount) Used for debugging.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

NO

public static final int NO

Used by some member fields to mean not present (e.g., norms, deletions).

See Also:

Constant Field Values

YES

public static final int YES

Used by some member fields to mean present (e.g., norms, deletions).

See Also:

Constant Field Values

name

public final String name

Unique segment name in the directory.

dir

public final Directory dir

Where this segment resides.

Constructor Detail

SegmentInfo

public SegmentInfo(Directory dir,
                   Version version,
                   Version minVersion,
                   String name,
                   int maxDoc,
                   boolean isCompoundFile,
                   Codec codec,
                   Map<String,String> diagnostics,
                   byte[] id,
                   Map<String,String> attributes,
                   Sort indexSort)

Construct a new complete SegmentInfo instance from input.

Note: this is public only to allow access from the codecs package.

Method Detail

getDiagnostics

public Map<String,String> getDiagnostics()

Returns diagnostics saved into the segment when it was written. The map is immutable.

getUseCompoundFile

public boolean getUseCompoundFile()

Returns true if this segment is stored as a compound file; else, false.

setCodec

public void setCodec(Codec codec)

Can only be called once.

getCodec

public Codec getCodec()

Return Codec that wrote this segment.

maxDoc

public int maxDoc()

Returns number of documents in this segment (deletions are not taken into account).

files

public Set<String> files()

Return all files referenced by this SegmentInfo.

toString

public String toString()

Overrides:

toString in class Object

toString

public String toString(int delCount)

Used for debugging. Format may suddenly change.

Current format looks like _a(3.1):c45/4:[sorter=<long: "timestamp">!], which means the segment's name is _a; it was created with Lucene 3.1 (or '?' if it's unknown); it's using compound file format (would be C if not compound); it has 45 documents; it has 4 deletions (this part is left off when there are no deletions); it is sorted by the timestamp field in descending order (this part is omitted for unsorted segments).

equals

public boolean equals(Object obj)

We consider another SegmentInfo instance equal if it has the same dir and same name.

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

getVersion

public Version getVersion()

Returns the version of the code which wrote the segment.

getMinVersion

public Version getMinVersion()

Return the minimum Lucene version that contributed documents to this segment, or null if it is unknown.

getId

public byte[] getId()

Return the id that uniquely identifies this segment.

setFiles

public void setFiles(Collection<String> files)

Sets the files written for this segment.

addFiles

public void addFiles(Collection<String> files)

Add these files to the set of files written for this segment.

addFile

public void addFile(String file)

Add this file to the set of files written for this segment.

getAttribute

public String getAttribute(String key)

Get a codec attribute value, or null if it does not exist

putAttribute

public String putAttribute(String key,
                           String value)

Puts a codec attribute value.

This is a key-value mapping for the field that the codec can use to store additional metadata, and will be available to the codec when reading the segment via getAttribute(String)

If a value already exists for the field, it will be replaced with the new value. This method make a copy on write for every attribute change.

getAttributes

public Map<String,String> getAttributes()

Returns the internal codec attributes map.

Returns:

internal codec attributes map.

getIndexSort

public Sort getIndexSort()

Return the sort order of this segment, or null if the index has no sort.