net.bull.javamelody

Class RrdNioBackend

java.lang.Object

org.jrobin.core.RrdBackend

org.jrobin.core.RrdFileBackend

net.bull.javamelody.RrdNioBackend

public class RrdNioBackend
extends org.jrobin.core.RrdFileBackend

JRobin backend which is used to store RRD data to ordinary disk files by using fast java.nio.* package. This is the default backend engine since JRobin 1.4.0.

Field Summary

Fields inherited from class org.jrobin.core.RrdFileBackend

file, readOnly

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	RrdNioBackend(String path, boolean readOnly, int syncPeriod) Creates RrdFileBackend object for the given file path, backed by java.nio.* classes.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Closes the underlying RRD file.
static Timer	getFileSyncTimer()
protected void	read(long offset, byte[] b) Reads a number of bytes from the RRD file on the disk
static void	setFileSyncTimer(Timer timer) Sets the timer.
protected void	setLength(long newLength) Sets length of the underlying RRD file.
protected void	sync() This method forces all data cached in memory but not yet stored in the file, to be stored in it.
protected void	write(long offset, byte[] b) Writes bytes to the underlying RRD file on the disk

Methods inherited from class org.jrobin.core.RrdFileBackend

getCanonicalPath, getCanonicalPath, getLength

Methods inherited from class org.jrobin.core.RrdBackend

getPath, isCachingAllowed, readAll

Methods inherited from class java.lang.Object

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

Constructor Detail

RrdNioBackend

protected RrdNioBackend(String path,
             boolean readOnly,
             int syncPeriod)
                 throws IOException

Creates RrdFileBackend object for the given file path, backed by java.nio.* classes.

Parameters:

path - Path to a file

readOnly - True, if file should be open in a read-only mode. False otherwise

syncPeriod - See RrdNioBackendFactory.setSyncPeriod(int) for explanation

Throws:

IOException - Thrown in case of I/O error

Method Detail

getFileSyncTimer

public static Timer getFileSyncTimer()

Returns:

The timer to synchronize files.

setFileSyncTimer

public static void setFileSyncTimer(Timer timer)

Sets the timer.

Parameters:

timer - timer to synchronize files.

setLength

protected void setLength(long newLength)
                  throws IOException

Sets length of the underlying RRD file. This method is called only once, immediately after a new RRD file gets created.

Overrides:

setLength in class org.jrobin.core.RrdFileBackend

Parameters:

newLength - Length of the RRD file

Throws:

IOException - Thrown in case of I/O error.

write

protected void write(long offset,
         byte[] b)
              throws IOException

Writes bytes to the underlying RRD file on the disk

Overrides:

write in class org.jrobin.core.RrdFileBackend

Parameters:

offset - Starting file offset

b - Bytes to be written.

Throws:

IOException

read

protected void read(long offset,
        byte[] b)
             throws IOException

Reads a number of bytes from the RRD file on the disk

Overrides:

read in class org.jrobin.core.RrdFileBackend

Parameters:

offset - Starting file offset

b - Buffer which receives bytes read from the file.

Throws:

IOException

close

public void close()
           throws IOException

Closes the underlying RRD file.

Overrides:

close in class org.jrobin.core.RrdFileBackend

Throws:

IOException - Thrown in case of I/O error

sync

protected void sync()

This method forces all data cached in memory but not yet stored in the file, to be stored in it.