public abstract class

IndexCommit

extends Object
implements Comparable<T>
java.lang.Object
   ↳ org.apache.lucene.index.IndexCommit
Known Direct Subclasses

Class Overview

Expert: represents a single commit into an index as seen by the IndexDeletionPolicy or IndexReader.

Changes to the content of an index are made visible only after the writer who made that change commits by writing a new segments file (segments_N). This point in time, when the action of writing of a new segments file to the directory is completed, is an index commit.

Each index commit point has a unique segments file associated with it. The segments file associated with a later index commit point would have a larger N.

Summary

Public Constructors
IndexCommit()
Public Methods
int compareTo(IndexCommit commit)
abstract void delete()
Delete this commit point.
boolean equals(Object other)
Two IndexCommits are equal if both their Directory and versions are equal.
abstract Directory getDirectory()
Returns the Directory for the index.
abstract Collection<String> getFileNames()
Returns all index files referenced by this commit point.
abstract long getGeneration()
Returns the generation (the _N in segments_N) for this IndexCommit
abstract String getSegmentsFileName()
Get the segments file (segments_N) associated with this commit point.
long getTimestamp()
Convenience method that returns the last modified time of the segments_N file corresponding to this index commit, equivalent to getDirectory().fileModified(getSegmentsFileName()).
abstract Map<StringString> getUserData()
Returns userData, previously passed to commit(Map) for this commit.
abstract long getVersion()
Returns the version for this IndexCommit.
int hashCode()
abstract boolean isDeleted()
abstract boolean isOptimized()
Returns true if this commit is an optimized index.
[Expand]
Inherited Methods
From class java.lang.Object
From interface java.lang.Comparable

Public Constructors

public IndexCommit ()

Public Methods

public int compareTo (IndexCommit commit)

public abstract void delete ()

Delete this commit point. This only applies when using the commit point in the context of IndexWriter's IndexDeletionPolicy.

Upon calling this, the writer is notified that this commit point should be deleted.

Decision that a commit-point should be deleted is taken by the IndexDeletionPolicy in effect and therefore this should only be called by its onInit() or onCommit() methods.

public boolean equals (Object other)

Two IndexCommits are equal if both their Directory and versions are equal.

public abstract Directory getDirectory ()

Returns the Directory for the index.

public abstract Collection<String> getFileNames ()

Returns all index files referenced by this commit point.

Throws
IOException

public abstract long getGeneration ()

Returns the generation (the _N in segments_N) for this IndexCommit

public abstract String getSegmentsFileName ()

Get the segments file (segments_N) associated with this commit point.

public long getTimestamp ()

Convenience method that returns the last modified time of the segments_N file corresponding to this index commit, equivalent to getDirectory().fileModified(getSegmentsFileName()).

Throws
IOException

public abstract Map<StringString> getUserData ()

Returns userData, previously passed to commit(Map) for this commit. Map is String -> String.

Throws
IOException

public abstract long getVersion ()

Returns the version for this IndexCommit. This is the same value that getVersion() would return if it were opened on this commit.

public int hashCode ()

public abstract boolean isDeleted ()

public abstract boolean isOptimized ()

Returns true if this commit is an optimized index.