com.yammer.metrics.stats
Class UniformSample

java.lang.Object
  com.yammer.metrics.stats.UniformSample

All Implemented Interfaces:

Sample

public class UniformSample
extends Object
implements Sample

A random sample of a stream of longs. Uses Vitter's Algorithm R to produce a statistically representative sample.

See Also:

Random Sampling with a Reservoir

Constructor Summary

UniformSample(int reservoirSize)
Creates a new UniformSample.

Method Summary

void	clear() Clears all recorded values.
void	dump(File output) Writes the values of the sample to the given file.
int	size() Returns the number of values recorded.
void	update(long value) Adds a new recorded value to the sample.
List<Long>	values() Returns a copy of the sample's values.

Methods inherited from class java.lang.Object

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

Constructor Detail

UniformSample

public UniformSample(int reservoirSize)

Creates a new UniformSample.

Parameters:

reservoirSize - the number of samples to keep in the sampling reservoir

Method Detail

clear

public void clear()

Description copied from interface: Sample

Clears all recorded values.

Specified by:

clear in interface Sample

size

public int size()

Description copied from interface: Sample

Returns the number of values recorded.

Specified by:

size in interface Sample

Returns:

the number of values recorded

update

public void update(long value)

Description copied from interface: Sample

Adds a new recorded value to the sample.

Specified by:

update in interface Sample

Parameters:

value - a new recorded value

values

public List<Long> values()

Description copied from interface: Sample

Returns a copy of the sample's values.

Specified by:

values in interface Sample

Returns:

a copy of the sample's values

dump

public void dump(File output)
          throws IOException

Description copied from interface: Sample

Writes the values of the sample to the given file.

Specified by:

dump in interface Sample

Parameters:

output - the file to which the values will be written

Throws:

IOException - if there is an error writing the values