java.lang.Object

org.apache.activeio.journal.active.JournalImpl

All Implemented Interfaces:: Journal

public final class JournalImpl extends Object implements Journal

A high speed Journal implementation. Inspired by the ideas of the Howl project but tailored to the needs of ActiveMQ.

This Journal provides the following features:

Concurrent writes are batched into a single write/force done by a background thread.
Uses preallocated logs to avoid disk fragmentation and performance degregation.
The number and size of the preallocated logs are configurable.
Uses direct ByteBuffers to write data to log files.
Allows logs to grow in case of an overflow condition so that overflow exceptions are not not thrown. Grown logs that are inactivate (due to a new mark) are resized to their original size.
No limit on the size of the record written to the journal
Should be possible to extend so that multiple physical disk are used concurrently to increase throughput and decrease latency.

Version:: $Revision: 1.1 $

Field Summary

Fields

Modifier and Type

Field

Description

static final int

DEFAULT_PACKET_SIZE

static final int

DEFAULT_POOL_SIZE
Constructor Summary

Constructors

Constructor

Description

JournalImpl(File logDirectory)

JournalImpl(File logDirectory, int logFileCount, int logFileSize)

JournalImpl(File logDirectory, int logFileCount, int logFileSize, File archiveDirectory)

JournalImpl(LogFileManager logFile)
Method Summary

Modifier and Type

Method

Description

void

close()

Deprecated.
@see #dispose()

void

dispose()

int

getInitialLogFileSize()

File

getLogDirectory()

RecordLocation

getMark()

Obtains the mark that was set in the Journal.

RecordLocation

getNextRecordLocation(RecordLocation lastLocation)

Allows you to get the next RecordLocation after the location that is in the journal.

protected IOException

handleExecutionException(ExecutionException e)

Packet

read(RecordLocation l)

Reads a previously written record from the journal.

void

setJournalEventListener(JournalEventListener eventListener)

Registers a JournalEventListener that will receive notifications from the Journal.

void

setMark(RecordLocation l, boolean force)

Informs the journal that all the journal space up to the location is no longer needed and can be reclaimed for reuse.

String

toString()

RecordLocation

write(Packet data, boolean sync)

Writes a of data to the journal.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details
- DEFAULT_POOL_SIZE
  
  public static final int DEFAULT_POOL_SIZE
- DEFAULT_PACKET_SIZE
  
  public static final int DEFAULT_PACKET_SIZE
Constructor Details
- JournalImpl
  
  public JournalImpl(File logDirectory) throws IOException
  
  Throws:
  
  IOException
- JournalImpl
  
  public JournalImpl(File logDirectory, int logFileCount, int logFileSize) throws IOException
  
  Throws:
  
  IOException
- JournalImpl
  
  public JournalImpl(File logDirectory, int logFileCount, int logFileSize, File archiveDirectory) throws IOException
  
  Throws:
  
  IOException
- JournalImpl
  
  public JournalImpl(LogFileManager logFile)
Method Details
- write
  
  public RecordLocation write(Packet data, boolean sync) throws IOException
  
  Description copied from interface: Journal
  
  Writes a of data to the journal. If sync is true, then this call blocks until the data has landed on the physical disk. Otherwise, this enqueues the write request and returns.
  
  Specified by:
  
  write in interface Journal
  
  Parameters:
  
  sync - - If this call should block until the data lands on disk.
  
  Returns:
  
  RecordLocation the location where the data will be written to on disk.
  
  Throws:
  
  IOException - if the write failed.
- setMark
  
  public void setMark(RecordLocation l, boolean force) throws InvalidRecordLocationException, IOException
  
  Description copied from interface: Journal
  
  Informs the journal that all the journal space up to the location is no longer needed and can be reclaimed for reuse.
  
  Specified by:
  
  setMark in interface Journal
  
  Parameters:
  
  l - the location of the record to mark. All record locations before the marked location will no longger be vaild.
  
  force -
  
  recordLocator -
  
  Throws:
  
  InvalidRecordLocationException
  
  IOException
  
  InterruptedException
- getMark
  
  public RecordLocation getMark()
  
  Description copied from interface: Journal
  
  Obtains the mark that was set in the Journal.
  
  Specified by:
  
  getMark in interface Journal
  
  Returns:
- getNextRecordLocation
  
  public RecordLocation getNextRecordLocation(RecordLocation lastLocation) throws IOException, InvalidRecordLocationException
  
  Description copied from interface: Journal
  
  Allows you to get the next RecordLocation after the location that is in the journal.
  
  Specified by:
  
  getNextRecordLocation in interface Journal
  
  Parameters:
  
  lastLocation -
  
  Returns:
  
  Throws:
  
  IOException
  
  InvalidRecordLocationException
- handleExecutionException
  
  protected IOException handleExecutionException(ExecutionException e) throws IOException
  
  Throws:
  
  IOException
- read
  
  public Packet read(RecordLocation l) throws IOException, InvalidRecordLocationException
  
  Description copied from interface: Journal
  
  Reads a previously written record from the journal.
  
  Specified by:
  
  read in interface Journal
  
  Parameters:
  
  l - is where to read the record from.
  
  location -
  
  Returns:
  
  Throws:
  
  InvalidRecordLocationException
  
  IOException
- setJournalEventListener
  
  public void setJournalEventListener(JournalEventListener eventListener)
  
  Description copied from interface: Journal
  
  Registers a JournalEventListener that will receive notifications from the Journal.
  
  Specified by:
  
  setJournalEventListener in interface Journal
  
  Parameters:
  
  eventListener - object that will receive journal events.
- close
  
  public void close() throws IOException
  
  Deprecated.
  @see #dispose()
  
  Description copied from interface: Journal
  
  Close the Journal. This is blocking operation that waits for any pending put opperations to be forced to disk. Once the Journal is closed, all other methods of the journal should throw IllegalStateException.
  
  Specified by:
  
  close in interface Journal
  
  Throws:
  
  IOException - if an error occurs while the journal is being closed.
- dispose
  
  public void dispose()
- getLogDirectory
  
  public File getLogDirectory()
  
  Returns:
- getInitialLogFileSize
  
  public int getInitialLogFileSize()
- toString
  
  public String toString()
  
  Overrides:
  
  toString in class Object

Class JournalImpl

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Details

DEFAULT_POOL_SIZE

DEFAULT_PACKET_SIZE

Constructor Details

JournalImpl

JournalImpl

JournalImpl

JournalImpl

Method Details

write

setMark

getMark

getNextRecordLocation

handleExecutionException

read

setJournalEventListener

close

dispose

getLogDirectory

getInitialLogFileSize

toString