Package org.rrd4j.core

Class ByteBufferBackend

java.lang.Object

org.rrd4j.core.RrdBackend

org.rrd4j.core.ByteBufferBackend

Direct Known Subclasses:

RrdByteArrayBackend, RrdMemoryBackend, RrdNioBackend

public abstract class ByteBufferBackend
extends RrdBackend

A backend that store and provides access to data using a ByteBuffer, using java internal methods for long, integer and others types.

Since:

3.4

Author:

Fabrice Bacchella

Field Summary

Fields inherited from class org.rrd4j.core.RrdBackend

BYTEORDER

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ByteBufferBackend(String path)

Method Summary

Modifier and Type	Method	Description
protected void	close()	Closes the underlying backend.
protected CharBuffer	getCharBuffer(long offset, int size)	Extract a CharBuffer from the backend, used by readString
protected boolean	isDirty()
protected void	read(long offset, byte[] b)	Reads a number of bytes from the RRD file on the disk
double	readDouble(long offset)
double[]	readDouble(long offset, int count)
protected int	readInt(long offset)
protected long	readLong(long offset)
protected short	readShort(long offset)
protected void	rrdClose()	Closes the underlying backend.
protected void	setByteBuffer(ByteBuffer byteBuffer)
protected void	write(long offset, byte[] b)	Writes bytes to the underlying RRD file on the disk
protected void	writeDouble(long offset, double value)
protected void	writeDouble(long offset, double[] values)
protected void	writeDouble(long offset, double value, int count)
protected void	writeInt(long offset, int value)
protected void	writeLong(long offset, long value)
protected void	writeShort(long offset, short value)
protected void	writeString(long offset, String value, int length)

Methods inherited from class org.rrd4j.core.RrdBackend

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

Methods inherited from class java.lang.Object

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

Constructor Detail

ByteBufferBackend

protected ByteBufferBackend(String path)

Method Detail

setByteBuffer

protected void setByteBuffer(ByteBuffer byteBuffer)

write

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

Writes bytes to the underlying RRD file on the disk

Specified by:

write in class RrdBackend

Parameters:

offset - Starting file offset

b - Bytes to be written.

Throws:

IOException - if any.

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

writeShort

protected void writeShort(long offset,
                          short value)
                   throws IOException

Overrides:

writeShort in class RrdBackend

Throws:

IOException

writeInt

protected void writeInt(long offset,
                        int value)
                 throws IOException

Overrides:

writeInt in class RrdBackend

Throws:

IOException

writeLong

protected void writeLong(long offset,
                         long value)
                  throws IOException

Overrides:

writeLong in class RrdBackend

Throws:

IOException

writeDouble

protected void writeDouble(long offset,
                           double value)
                    throws IOException

Overrides:

writeDouble in class RrdBackend

Throws:

IOException

writeDouble

protected void writeDouble(long offset,
                           double value,
                           int count)
                    throws IOException

Overrides:

writeDouble in class RrdBackend

Throws:

IOException

writeDouble

protected void writeDouble(long offset,
                           double[] values)
                    throws IOException

Overrides:

writeDouble in class RrdBackend

Throws:

IOException

writeString

protected void writeString(long offset,
                           String value,
                           int length)
                    throws IOException

Overrides:

writeString in class RrdBackend

Throws:

IOException

read

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

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

Specified by:

read in class RrdBackend

Parameters:

offset - Starting file offset

b - Buffer which receives bytes read from the file.

Throws:

IOException - Thrown in case of I/O error.

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

readShort

protected short readShort(long offset)
                   throws IOException

Overrides:

readShort in class RrdBackend

Throws:

IOException

readInt

protected int readInt(long offset)
               throws IOException

Overrides:

readInt in class RrdBackend

Throws:

IOException

readLong

protected long readLong(long offset)
                 throws IOException

Overrides:

readLong in class RrdBackend

Throws:

IOException

readDouble

public double readDouble(long offset)
                  throws IOException

Overrides:

readDouble in class RrdBackend

Throws:

IOException

readDouble

public double[] readDouble(long offset,
                           int count)
                    throws IOException

Overrides:

readDouble in class RrdBackend

Throws:

IOException

getCharBuffer

protected CharBuffer getCharBuffer(long offset,
                                   int size)
                            throws RrdException

Description copied from class: RrdBackend

Extract a CharBuffer from the backend, used by readString

Overrides:

getCharBuffer in class RrdBackend

Parameters:

offset - the offset in the rrd

size - the size of the buffer, in character

Returns:

a new CharBuffer

Throws:

RrdException

close

protected void close()
              throws IOException

Description copied from class: RrdBackend

Closes the underlying backend. Used internally, should not be called from external code.

Specified by:

close in class RrdBackend

Throws:

IOException - Thrown in case of I/O error

isDirty

protected boolean isDirty()

rrdClose

protected void rrdClose()
                 throws IOException

Description copied from class: RrdBackend

Closes the underlying backend. Call by RrdDb#close() when it's closed. All subclass must keep calling it.

Overrides:

rrdClose in class RrdBackend

Throws:

IOException - Thrown in case of I/O error