org.jrobin.core
Class Robin

java.lang.Object
  org.jrobin.core.Robin

public class Robin
extends Object

Class to represent archive values for a single datasource. Robin class is the heart of the so-called "round robin database" concept. Basically, each Robin object is a fixed length array of double values. Each double value reperesents consolidated, archived value for the specific timestamp. When the underlying array of double values gets completely filled, new values will replace the oldest ones.

Robin object does not hold values in memory - such object could be quite large. Instead of it, Robin reads them from the backend I/O only when necessary.

Author:

Sasa Markovic

Method Summary

void	copyStateTo(org.jrobin.core.RrdUpdater other) Copies object's internal state to another Robin object.
void	filterValues(double minValue, double maxValue) Filters values stored in this archive based on the given boundary.
Archive	getParent() Returns the Archive object to which this Robin object belongs.
org.jrobin.core.RrdAllocator	getRrdAllocator() Required to implement RrdUpdater interface.
RrdBackend	getRrdBackend() Returns the underlying storage (backend) object which actually performs all I/O operations.
int	getSize() Returns the size of the underlying array of archived values.
double	getValue(int index) Returns the i-th value from the Robin archive.
double[]	getValues() Fetches all archived values.
void	setValue(int index, double value) Sets the i-th value in the Robin archive.
void	setValues(double newValue) (Re)sets all values in this archive to the same value.
void	setValues(double[] newValues) Updates archived values in bulk.

Methods inherited from class java.lang.Object

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

Method Detail

getValues

public double[] getValues()
                   throws IOException

Fetches all archived values.

Returns:

Array of double archive values, starting from the oldest one.

Throws:

IOException - Thrown in case of I/O specific error.

setValues

public void setValues(double[] newValues)
               throws IOException,
                      RrdException

Updates archived values in bulk.

Parameters:

newValues - Array of double values to be stored in the archive

Throws:

IOException - Thrown in case of I/O error

RrdException - Thrown if the length of the input array is different from the length of this archive

setValues

public void setValues(double newValue)
               throws IOException

(Re)sets all values in this archive to the same value.

Parameters:

newValue - New value

Throws:

IOException - Thrown in case of I/O error

getValue

public double getValue(int index)
                throws IOException

Returns the i-th value from the Robin archive.

Parameters:

index - Value index

Returns:

Value stored in the i-th position (the oldest value has zero index)

Throws:

IOException - Thrown in case of I/O specific error.

setValue

public void setValue(int index,
                     double value)
              throws IOException

Sets the i-th value in the Robin archive.

Parameters:

index - index in the archive (the oldest value has zero index)

value - value to be stored

Throws:

IOException - Thrown in case of I/O specific error.

getParent

public Archive getParent()

Returns the Archive object to which this Robin object belongs.

Returns:

Parent Archive object

getSize

public int getSize()

Returns the size of the underlying array of archived values.

Returns:

Number of stored values

copyStateTo

public void copyStateTo(org.jrobin.core.RrdUpdater other)
                 throws IOException,
                        RrdException

Copies object's internal state to another Robin object.

Parameters:

other - New Robin object to copy state to

Throws:

IOException - Thrown in case of I/O error

RrdException - Thrown if supplied argument is not a Robin object

filterValues

public void filterValues(double minValue,
                         double maxValue)
                  throws IOException

Filters values stored in this archive based on the given boundary. Archived values found to be outside of [minValue, maxValue] interval (inclusive) will be silently replaced with NaN.

Parameters:

minValue - lower boundary

maxValue - upper boundary

Throws:

IOException - Thrown in case of I/O error

getRrdBackend

public RrdBackend getRrdBackend()

Returns the underlying storage (backend) object which actually performs all I/O operations.

Returns:

I/O backend object

getRrdAllocator

public org.jrobin.core.RrdAllocator getRrdAllocator()

Required to implement RrdUpdater interface. You should never call this method directly.

Returns:

Allocator object