alluxio.master.journalv0.ufs

Class UfsJournal

java.lang.Object

alluxio.master.journalv0.ufs.UfsJournal

All Implemented Interfaces:

Journal

Direct Known Subclasses:

UfsMutableJournal

@ThreadSafe
public class UfsJournal
extends Object
implements Journal

Implementation of UFS-based journal. The journal is made up of 2 components: - The checkpoint: the full state of the master - The entries: incremental entries to apply to the checkpoint. To construct the full state of the master, all the entries must be applied to the checkpoint in order. The entry file most recently being written to is in the base journal folder, where the completed entry files are in the "completed" folder.

Nested Class Summary

Nested classes/interfaces inherited from interface alluxio.master.journalv0.Journal

Journal.Factory

Field Summary

Fields

Modifier and Type	Field and Description
protected static long	FIRST_COMPLETED_LOG_NUMBER The log number for the first completed log.
protected URI	mLocation The location where this journal is stored.

Constructor Summary

Constructors

Constructor and Description
UfsJournal(URI location) Creates a new instance of UfsJournal.

Method Summary

Modifier and Type	Method and Description
protected URI	getCheckpoint()
URI	getCompletedLocation()
protected URI	getCompletedLog(long logNumber)
URI	getCurrentLog()
protected JournalFormatter	getJournalFormatter()
URI	getLocation()
JournalReader	getReader()
boolean	isFormatted()

Methods inherited from class java.lang.Object

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

Field Detail

FIRST_COMPLETED_LOG_NUMBER

protected static final long FIRST_COMPLETED_LOG_NUMBER

The log number for the first completed log.

See Also:

Constant Field Values

mLocation

protected final URI mLocation

The location where this journal is stored.

Constructor Detail

UfsJournal

public UfsJournal(URI location)

Creates a new instance of UfsJournal.

Parameters:

location - the location for this journal

Method Detail

getCompletedLocation

public URI getCompletedLocation()

Returns:

the location of the completed logs

getCheckpoint

protected URI getCheckpoint()

Returns:

the location of the journal checkpoint

getCurrentLog

public URI getCurrentLog()

Returns:

the location of the current log

getCompletedLog

protected URI getCompletedLog(long logNumber)

Parameters:

logNumber - the log number to get the path for

Returns:

the location of the completed log for a particular log number

getJournalFormatter

protected JournalFormatter getJournalFormatter()

Returns:

the JournalFormatter for this journal

getLocation

public URI getLocation()

Specified by:

getLocation in interface Journal

Returns:

the journal location

getReader

public JournalReader getReader()

Specified by:

getReader in interface Journal

Returns:

the JournalReader for this journal

isFormatted

public boolean isFormatted()
                    throws IOException

Specified by:

isFormatted in interface Journal

Returns:

whether the journal has been formatted

Throws:

IOException