org.rrd4j.core

Class RrdByteArrayBackend

java.lang.Object

org.rrd4j.core.RrdBackend

org.rrd4j.core.RrdByteArrayBackend

Direct Known Subclasses:

RrdBerkeleyDbBackend, RrdMemoryBackend, RrdMongoDBBackend

public abstract class RrdByteArrayBackend
extends RrdBackend

Abstract byte array based backend.

Field Summary

Fields

Modifier and Type	Field and Description
protected byte[]	buffer

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	RrdByteArrayBackend(String path) Constructor for RrdByteArrayBackend.

Method Summary

Methods

Modifier and Type	Method and 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 RRD4J classes.
protected void	read(long offset, byte[] bytes) read.
protected void	setLength(long length) Sets the number of bytes in the underlying RRD storage.
protected void	write(long offset, byte[] bytes) write.

Methods inherited from class org.rrd4j.core.RrdBackend

getPath, readAll

Methods inherited from class java.lang.Object

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

Field Detail

buffer

protected byte[] buffer

Constructor Detail

RrdByteArrayBackend

protected RrdByteArrayBackend(String path)

Constructor for RrdByteArrayBackend.

Parameters:

path - a String object.

Method Detail

write

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

write.

Specified by:

write in class RrdBackend

Parameters:

offset - a long.

bytes - an array of byte.

Throws:

IOException - if any.

read

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

read.

Specified by:

read in class RrdBackend

Parameters:

offset - a long.

bytes - an array of byte.

Throws:

IOException - if any.

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 length)
                  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. Reserves a memory section as a RRD storage.

Specified by:

setLength in class RrdBackend

Parameters:

length - Length of the underlying RRD storage in bytes.

Throws:

IOException - Thrown in case of I/O error.

close

public void close()
           throws IOException

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

Overrides:

close in class RrdBackend

Throws:

IOException - if any.

isCachingAllowed

protected boolean isCachingAllowed()

This method is overridden to disable high-level caching in frontend RRD4J 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.