org.apache.cassandra.db.commitlog
Class CommitLogSegment

java.lang.Object
  org.apache.cassandra.db.commitlog.CommitLogSegment

public class CommitLogSegment
extends java.lang.Object

Field Summary

long

id

Method Summary

void	close() Close the segment file.
boolean	contains(ReplayPosition context) Check to see if a certain ReplayPosition is contained by this segment file.
java.lang.String	dirtyString()
void	discard(boolean deleteFile) Completely discards a segment file by deleting it.
static CommitLogSegment	freshSegment()
ReplayPosition	getContext()
java.util.Collection<java.lang.Integer>	getDirtyCFIDs()
java.lang.String	getName()
java.lang.String	getPath()
boolean	hasCapacityFor(RowMutation mutation)
static long	idFromFilename(java.lang.String filename) Extracts the commit log ID from filename
boolean	isUnused()
void	markClean(java.lang.Integer cfId, ReplayPosition context) Marks the ColumnFamily specified by cfId as clean for this log segment.
int	position()
static boolean	possibleCommitLogFile(java.lang.String filename)
CommitLogSegment	recycle() Recycle processes an unneeded segment file for reuse.
void	sync() Forces a disk flush for this segment file.
java.lang.String	toString()
ReplayPosition	write(RowMutation rowMutation) Appends a row mutation onto the commit log.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

id

public final long id

Method Detail

freshSegment

public static CommitLogSegment freshSegment()

Returns:

a newly minted segment file

idFromFilename

public static long idFromFilename(java.lang.String filename)

Extracts the commit log ID from filename

Parameters:

filename - the filename of the commit log file

Returns:

the extracted commit log ID

possibleCommitLogFile

public static boolean possibleCommitLogFile(java.lang.String filename)

Parameters:

filename - the filename to check

Returns:

true if filename could be a commit log based on it's filename

discard

public void discard(boolean deleteFile)

Completely discards a segment file by deleting it. (Potentially blocking operation)

recycle

public CommitLogSegment recycle()

Recycle processes an unneeded segment file for reuse.

Returns:

a new CommitLogSegment representing the newly reusable segment.

hasCapacityFor

public boolean hasCapacityFor(RowMutation mutation)

Returns:

true if there is room to write() @param mutation to this segment

write

public ReplayPosition write(RowMutation rowMutation)
                     throws java.io.IOException

Appends a row mutation onto the commit log. Requres that hasCapacityFor has already been checked.

Parameters:

rowMutation - the mutation to append to the commit log.

Returns:

the position of the appended mutation

Throws:

java.io.IOException

sync

public void sync()
          throws java.io.IOException

Forces a disk flush for this segment file.

Throws:

java.io.IOException

getContext

public ReplayPosition getContext()

Returns:

the current ReplayPosition for this log segment

getPath

public java.lang.String getPath()

Returns:

the file path to this segment

getName

public java.lang.String getName()

Returns:

the file name of this segment

close

public void close()

Close the segment file.

markClean

public void markClean(java.lang.Integer cfId,
                      ReplayPosition context)

Marks the ColumnFamily specified by cfId as clean for this log segment. If the given context argument is contained in this file, it will only mark the CF as clean if no newer writes have taken place.

Parameters:

cfId - the column family ID that is now clean

context - the optional clean offset

getDirtyCFIDs

public java.util.Collection<java.lang.Integer> getDirtyCFIDs()

Returns:

a collection of dirty CFIDs for this segment file.

isUnused

public boolean isUnused()

Returns:

true if this segment is unused and safe to recycle or delete

contains

public boolean contains(ReplayPosition context)

Check to see if a certain ReplayPosition is contained by this segment file.

Parameters:

context - the replay position to be checked

Returns:

true if the replay position is contained by this segment file.

dirtyString

public java.lang.String dirtyString()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

position

public int position()