Package org.jrobin.core

Class RrdMemoryBackend

java.lang.Object

org.jrobin.core.RrdBackend

org.jrobin.core.RrdMemoryBackend

public class RrdMemoryBackend
extends RrdBackend

Backend to be used to store all RRD bytes in memory.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	RrdMemoryBackend(String path)

Method Summary

Modifier and Type	Method	Description
void	close()	This method is required by the base class definition, but it does not releases any memory resources at all.
long	getLength()	Returns the number of RRD bytes held in memory.
protected boolean	isCachingAllowed()	This method is overridden to disable high-level caching in frontend JRobin classes.
protected void	read(long offset, byte[] b)	Reads an array of bytes from the underlying storage starting from the given storage offset.
protected void	setLength(long newLength)	Reserves a memory section as a RRD storage.
protected void	write(long offset, byte[] b)	Writes an array of bytes to the underlying storage starting from the given storage offset.

Methods inherited from class org.jrobin.core.RrdBackend

getPath, isInstanceCreated, isReadOnly, readAll, readDouble, readDouble, readInt, readLong, readString, writeDouble, writeDouble, writeDouble, writeInt, writeLong, writeString

Methods inherited from class java.lang.Object

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

Constructor Detail

RrdMemoryBackend

protected RrdMemoryBackend(String path)

Method Detail

write

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

Description copied from class: RrdBackend

Writes an array of bytes to the underlying storage starting from the given storage offset.

Specified by:

write in class RrdBackend

Parameters:

offset - Storage offset.

b - Array of bytes that should be copied to the underlying storage

read

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

Description copied from class: RrdBackend

Reads an array of bytes from the underlying storage starting from the given storage offset.

Specified by:

read in class RrdBackend

Parameters:

offset - Storage offset.

b - Array which receives bytes from the underlying storage

Throws:

IOException - Thrown in case of I/O error

getLength

public long getLength()

Returns the number of RRD bytes held in memory.

Specified by:

getLength in class RrdBackend

Returns:

Number of all RRD bytes.

setLength

protected void setLength(long newLength)
                  throws IOException

Reserves a memory section as a RRD storage.

Specified by:

setLength in class RrdBackend

Parameters:

newLength - Number of bytes held in memory.

Throws:

IOException - Thrown in case of I/O error.

close

public void close()

This method is required by the base class definition, but it does not releases any memory resources at all.

Overrides:

close in class RrdBackend

isCachingAllowed

protected boolean isCachingAllowed()

This method is overridden to disable high-level caching in frontend JRobin classes.

Overrides:

isCachingAllowed in class RrdBackend

Returns:

Always returns false. There is no need to cache anything in high-level classes since all RRD bytes are already in memory.