Package org.rrd4j.core

Class RrdNioBackend

java.lang.Object

org.rrd4j.core.RrdBackend

org.rrd4j.core.ByteBufferBackend

org.rrd4j.core.RrdNioBackend

All Implemented Interfaces:

RrdFileBackend

public class RrdNioBackend
extends ByteBufferBackend
implements RrdFileBackend

Backend which is used to store RRD data to ordinary disk files using java.nio.* package. This is the default backend engine.

Field Summary

Fields inherited from class org.rrd4j.core.RrdBackend

BYTEORDER

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the underlying RRD file.
String	getCanonicalPath()	Returns canonical path to the file on the disk.
long	getLength()	Returns the number of RRD bytes in the underlying storage.
protected void	setLength(long newLength)	Sets the number of bytes in the underlying RRD storage.
protected void	sync()	This method forces all data cached in memory but not yet stored in the file, to be stored in it.

Methods inherited from class org.rrd4j.core.ByteBufferBackend

getCharBuffer, isDirty, read, readDouble, readDouble, readInt, readLong, readShort, rrdClose, setByteBuffer, write, writeDouble, writeDouble, writeDouble, writeInt, writeLong, writeShort, writeString

Methods inherited from class org.rrd4j.core.RrdBackend

done, getFactory, getPath, getUri, isCachingAllowed, isInstanceCreated, readAll, readString, writeString

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,
                        RrdSyncThreadPool threadPool,
                        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

threadPool - a RrdSyncThreadPool object, it can be null.

Throws:

IOException - Thrown in case of I/O error

Method Detail

setLength

protected void setLength(long newLength)
                  throws IOException

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

Specified by:

setLength in class RrdBackend

Parameters:

newLength - Length of the underlying RRD storage in bytes.

Throws:

IllegalArgumentException - if the length is bigger that the possible mapping position (2GiB).

IOException - Thrown in case of I/O error.

close

public void close()
           throws IOException

Closes the underlying RRD file.

Overrides:

close in class ByteBufferBackend

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.

getLength

public long getLength()
               throws IOException

Description copied from class: RrdBackend

Returns the number of RRD bytes in the underlying storage.

Specified by:

getLength in class RrdBackend

Returns:

Number of RRD bytes in the storage.

Throws:

IOException - Thrown in case of I/O error.

getCanonicalPath

public String getCanonicalPath()
                        throws IOException

Description copied from interface: RrdFileBackend

Returns canonical path to the file on the disk.

Specified by:

getCanonicalPath in interface RrdFileBackend

Returns:

Canonical file path

Throws:

IOException - Thrown in case of I/O error