Module org.apache.jena.tdb

Package org.apache.jena.tdb1.transaction

Class Journal

java.lang.Object

org.apache.jena.tdb1.transaction.Journal

All Implemented Interfaces:

org.apache.jena.atlas.lib.Closeable

public final class Journal
extends Object
implements org.apache.jena.atlas.lib.Closeable

The Journal is slightly odd - it is append-only for write but random read. The write performance is more important than read; reads only happen if the journal grows to the point where it needs to free up cache.

Constructor Summary

Constructors

Constructor	Description
Journal(BufferChannel chan)

Method Summary

Modifier and Type	Method	Description
void	abortWrite()
void	append()
void	close()
void	commitWrite()
static Journal	create(Location location)
void	endWrite()
Iterator<JournalEntry>	entries()
Iterator<JournalEntry>	entries(long startPosition)
static boolean	exists(Location location)
String	getFilename()
boolean	isEmpty()
long	position()
void	position(long posn)
JournalEntry	readJournal(long id)
void	reopen()	Forced reopen - thread.interrupt causes java to close file.
long	size()
void	startWrite()	journal.startWrite(); try { journal.write journal.commitWrite(); } catch (Thowable ex) { journal.abortWrite(); } finally { journal.endWrite(); }
void	sync()
void	truncate(long size)
long	write(JournalEntryType type, FileRef fileRef, Block block)
long	writeJournal(JournalEntry entry)
long	writeStartPosn()

Methods inherited from class java.lang.Object

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

Constructor Details

Journal

public Journal(BufferChannel chan)

Method Details

exists

public static boolean exists(Location location)

create

public static Journal create(Location location)

reopen

public void reopen()

Forced reopen - thread.interrupt causes java to close file. Attempt to close, open, and position.

writeJournal

public long writeJournal(JournalEntry entry)

write

public long write(JournalEntryType type,
 FileRef fileRef,
 Block block)

readJournal

public JournalEntry readJournal(long id)

entries

public Iterator<JournalEntry> entries()

entries

public Iterator<JournalEntry> entries(long startPosition)

startWrite

public void startWrite()

 journal.startWrite();
 try {
         journal.write
         journal.commitWrite();
 } catch (Thowable ex) { journal.abortWrite(); }
 finally { journal.endWrite(); }
 

writeStartPosn

public long writeStartPosn()

commitWrite

public void commitWrite()

abortWrite

public void abortWrite()

endWrite

public void endWrite()

sync

public void sync()

close

public void close()

Specified by:

close in interface org.apache.jena.atlas.lib.Closeable

size

public long size()

isEmpty

public boolean isEmpty()

truncate

public void truncate(long size)

append

public void append()

position

public long position()

position

public void position(long posn)

getFilename

public String getFilename()