alluxio.master.journal.noop

Class NoopJournalSystem

java.lang.Object

alluxio.master.journal.noop.NoopJournalSystem

All Implemented Interfaces:

JournalSystem

public final class NoopJournalSystem
extends Object
implements JournalSystem

Journal system which doesn't do anything.

Nested Class Summary

Nested classes/interfaces inherited from interface alluxio.master.journal.JournalSystem

JournalSystem.Builder, JournalSystem.Mode

Constructor Summary

Constructors

Constructor and Description
NoopJournalSystem() Constructs a new NoopJournalSystem.

Method Summary

Modifier and Type	Method and Description
void	addJournalSink(Master master, JournalSink journalSink)
void	checkpoint() Creates a checkpoint in the primary master journal system.
Journal	createJournal(Master master) Creates a journal for the given state machine.
void	format() Formats the journal system.
void	gainPrimacy() Transitions the journal to primary mode.
Set<JournalSink>	getJournalSinks(Master master)
boolean	isEmpty() Returns whether the journal is formatted and has not had any entries written to it yet.
boolean	isFormatted()
void	losePrimacy() Transitions the journal to secondary mode.
void	removeJournalSink(Master master, JournalSink journalSink)
void	start() Starts the journal system.
void	stop() Stops the journal system.

Methods inherited from class java.lang.Object

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

Constructor Detail

NoopJournalSystem

public NoopJournalSystem()

Constructs a new NoopJournalSystem.

Method Detail

createJournal

public Journal createJournal(Master master)

Description copied from interface: JournalSystem

Creates a journal for the given state machine. The returned journal can create journal contexts for writing journal entries. However, no entries may be written until the journal system has been started, and entries may only be written when the journal system is in PRIMARY mode. When the journal is started in secondary mode, it will call Journaled#processJournalEntry(JournalEntry) and Journaled.resetState() to keep the state machine's state in sync with the entries written to the journal.

Specified by:

createJournal in interface JournalSystem

Parameters:

master - the master to create the journal for

Returns:

a new instance of Journal

gainPrimacy

public void gainPrimacy()

Description copied from interface: JournalSystem

Transitions the journal to primary mode.

Specified by:

gainPrimacy in interface JournalSystem

losePrimacy

public void losePrimacy()

Description copied from interface: JournalSystem

Transitions the journal to secondary mode.

Specified by:

losePrimacy in interface JournalSystem

isFormatted

public boolean isFormatted()

Specified by:

isFormatted in interface JournalSystem

Returns:

whether the journal system has been formatted

addJournalSink

public void addJournalSink(Master master,
                           JournalSink journalSink)

Specified by:

addJournalSink in interface JournalSystem

Parameters:

master - the master for which to add the journal sink

journalSink - the journal sink to add

removeJournalSink

public void removeJournalSink(Master master,
                              JournalSink journalSink)

Specified by:

removeJournalSink in interface JournalSystem

Parameters:

master - the master from which to remove the journal sink

journalSink - the journal sink to remove

getJournalSinks

public Set<JournalSink> getJournalSinks(@Nullable
                                        Master master)

Specified by:

getJournalSinks in interface JournalSystem

Parameters:

master - the master to get the journal sinks for, or null to get all sinks

Returns:

a set of JournalSink for the given master, or all sinks if master is null

isEmpty

public boolean isEmpty()

Description copied from interface: JournalSystem

Returns whether the journal is formatted and has not had any entries written to it yet. This can only be determined when the journal system is in primary mode because entries are written to the primary first.

Specified by:

isEmpty in interface JournalSystem

Returns:

whether the journal system is freshly formatted

format

public void format()

Description copied from interface: JournalSystem

Formats the journal system.

Specified by:

format in interface JournalSystem

start

public void start()

Description copied from interface: JournalSystem

Starts the journal system. All journals must be created before starting the journal system. This method will block until the journal system is successfully started. The journal always starts in secondary mode.

Specified by:

start in interface JournalSystem

stop

public void stop()

Description copied from interface: JournalSystem

Stops the journal system.

Specified by:

stop in interface JournalSystem

checkpoint

public void checkpoint()

Description copied from interface: JournalSystem

Creates a checkpoint in the primary master journal system.

Specified by:

checkpoint in interface JournalSystem