alluxio.master.journal.ufs

Class UfsJournalLogWriter

java.lang.Object

alluxio.master.journal.ufs.UfsJournalLogWriter

All Implemented Interfaces:

JournalWriter, Closeable, AutoCloseable

@ThreadSafe
public final class UfsJournalLogWriter
extends Object
implements JournalWriter

Class for writing journal edit log entries from the primary master. It marks the current log complete (so that it is visible to the standby masters) when the current log is large enough. When a new journal writer is created, it also marks the current log complete if there is one. A journal garbage collector thread is created when the writer is created, and is stopped when the writer is closed.

Constructor Summary

Constructors

Constructor and Description
UfsJournalLogWriter(UfsJournal journal, long nextSequenceNumber) Creates a new instance of UfsJournalLogWriter.

Method Summary

Modifier and Type	Method and Description
void	close()
void	flush() Flushes all the entries written to the underlying storage.
long	getNextSequenceNumber()
void	write(Journal.JournalEntry entry) Writes an entry.

Methods inherited from class java.lang.Object

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

Constructor Detail

UfsJournalLogWriter

public UfsJournalLogWriter(UfsJournal journal,
                           long nextSequenceNumber)
                    throws IOException

Creates a new instance of UfsJournalLogWriter.

Parameters:

journal - the handle to the journal

nextSequenceNumber - the sequence number to begin writing at

Throws:

IOException

Method Detail

write

public void write(Journal.JournalEntry entry)
           throws IOException,
                  JournalClosedException

Description copied from interface: JournalWriter

Writes an entry. JournalWriter.flush() should be called afterwards if we want to make sure the entry is persisted.

Specified by:

write in interface JournalWriter

Parameters:

entry - the journal entry to write

Throws:

IOException

JournalClosedException

flush

public void flush()
           throws IOException,
                  JournalClosedException

Description copied from interface: JournalWriter

Flushes all the entries written to the underlying storage.

Specified by:

flush in interface JournalWriter

Throws:

IOException

JournalClosedException

close

public void close()

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

getNextSequenceNumber

public long getNextSequenceNumber()

Returns:

the next sequence number to write