alluxio.master.journalv0.ufs

Class UfsJournalWriter

java.lang.Object

alluxio.master.journalv0.ufs.UfsJournalWriter

All Implemented Interfaces:

JournalWriter

@ThreadSafe
public final class UfsJournalWriter
extends Object
implements JournalWriter

Implementation of JournalWriter based on UFS.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	UfsJournalWriter.EntryOutputStream This is the output stream for the journal entries after the checkpoint.

Method Summary

Modifier and Type	Method and Description
void	close() Closes the journal.
void	completeCurrentLog() Marks the current log as completed.
void	completeLogs() Marks all logs as completed.
void	deleteCompletedLogs() Deletes all of the completed logs.
void	flush() Flushes the current log stream.
JournalOutputStream	getCheckpointOutputStream(long latestSequenceNumber) Returns an output stream for the journal checkpoint.
long	getNextSequenceNumber()
void	recover() Recovers the checkpoint in case the master crashed while updating it previously.
void	write(Journal.JournalEntry entry) Writes an entry to the current log stream.

Methods inherited from class java.lang.Object

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

Method Detail

completeLogs

public void completeLogs()
                  throws IOException

Description copied from interface: JournalWriter

Marks all logs as completed.

Specified by:

completeLogs in interface JournalWriter

Throws:

IOException

getCheckpointOutputStream

public JournalOutputStream getCheckpointOutputStream(long latestSequenceNumber)
                                              throws IOException

Description copied from interface: JournalWriter

Returns an output stream for the journal checkpoint. The returned output stream is a singleton for this writer.

Specified by:

getCheckpointOutputStream in interface JournalWriter

Parameters:

latestSequenceNumber - the sequence number of the latest journal entry. This sequence number will be used to determine the next sequence numbers for the subsequent journal entries.

Returns:

the output stream for the journal checkpoint

Throws:

IOException

write

public void write(Journal.JournalEntry entry)
           throws IOException

Description copied from interface: JournalWriter

Writes an entry to the current log stream. JournalWriter.flush() should be called afterward to ensure the entry is persisted.

Specified by:

write in interface JournalWriter

Parameters:

entry - the journal entry to write

Throws:

IOException

flush

public void flush()
           throws IOException

Description copied from interface: JournalWriter

Flushes the current log stream. Otherwise this operation is a no-op.

Specified by:

flush in interface JournalWriter

Throws:

IOException

getNextSequenceNumber

public long getNextSequenceNumber()

Specified by:

getNextSequenceNumber in interface JournalWriter

Returns:

the next sequence number

close

public void close()
           throws IOException

Description copied from interface: JournalWriter

Closes the journal.

Specified by:

close in interface JournalWriter

Throws:

IOException

recover

public void recover()

Description copied from interface: JournalWriter

Recovers the checkpoint in case the master crashed while updating it previously.

Specified by:

recover in interface JournalWriter

deleteCompletedLogs

public void deleteCompletedLogs()
                         throws IOException

Description copied from interface: JournalWriter

Deletes all of the completed logs.

Specified by:

deleteCompletedLogs in interface JournalWriter

Throws:

IOException

completeCurrentLog

public void completeCurrentLog()
                        throws IOException

Description copied from interface: JournalWriter

Marks the current log as completed. If successful, the current log will no longer exist. The current log must be closed before this call.

Specified by:

completeCurrentLog in interface JournalWriter

Throws:

IOException