org.apache.commons.math.stat.descriptive
Class SynchronizedDescriptiveStatistics

java.lang.Object
  org.apache.commons.math.stat.descriptive.DescriptiveStatistics
      org.apache.commons.math.stat.descriptive.SynchronizedDescriptiveStatistics

All Implemented Interfaces:

java.io.Serializable, StatisticalSummary

public class SynchronizedDescriptiveStatistics
extends DescriptiveStatistics

Implementation of DescriptiveStatistics that is safe to use in a multithreaded environment. Multiple threads can safely operate on a single instance without causing runtime exceptions due to race conditions. In effect, this implementation makes modification and access methods atomic operations for a single instance. That is to say, as one thread is computing a statistic from the instance, no other thread can modify the instance nor compute another statistic.

Since:

1.2

Version:

$Revision: 608819 $ $Date: 2008-01-04 05:46:21 -0700 (Fri, 04 Jan 2008) $

See Also:

Serialized Form

Field Summary

Fields inherited from class org.apache.commons.math.stat.descriptive.DescriptiveStatistics

eDA, INFINITE_WINDOW, windowSize

Constructor Summary

SynchronizedDescriptiveStatistics()
Construct an instance with infinite window

SynchronizedDescriptiveStatistics(int window)
Construct an instance with finite window

Method Summary

void	addValue(double v) Adds the value to the dataset.
double	apply(UnivariateStatistic stat) Apply the given statistic to this univariate collection.
void	clear() Resets all statistics and storage
double	getElement(int index) Returns the element at the specified index
long	getN() Returns the number of available values
double	getStandardDeviation() Returns the standard deviation of the available values.
double[]	getValues() Returns the current set of values in an array of double primitives.
int	getWindowSize() Access the window size.
void	setWindowSize(int windowSize) WindowSize controls the number of values which contribute to the reported statistics.
java.lang.String	toString() Generates a text report displaying univariate statistics from values that have been added.

Methods inherited from class org.apache.commons.math.stat.descriptive.DescriptiveStatistics

getGeometricMean, getGeometricMeanImpl, getKurtosis, getKurtosisImpl, getMax, getMaxImpl, getMean, getMeanImpl, getMin, getMinImpl, getPercentile, getPercentileImpl, getSkewness, getSkewnessImpl, getSortedValues, getSum, getSumImpl, getSumsq, getSumsqImpl, getVariance, getVarianceImpl, newInstance, newInstance, setGeometricMeanImpl, setKurtosisImpl, setMaxImpl, setMeanImpl, setMinImpl, setPercentileImpl, setSkewnessImpl, setSumImpl, setSumsqImpl, setVarianceImpl

Methods inherited from class java.lang.Object

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

Constructor Detail

SynchronizedDescriptiveStatistics

public SynchronizedDescriptiveStatistics()

Construct an instance with infinite window

SynchronizedDescriptiveStatistics

public SynchronizedDescriptiveStatistics(int window)

Construct an instance with finite window

Parameters:

window - the finite window size.

Method Detail

addValue

public void addValue(double v)

Description copied from class: DescriptiveStatistics

Adds the value to the dataset. If the dataset is at the maximum size (i.e., the number of stored elements equals the currently configured windowSize), the first (oldest) element in the dataset is discarded to make room for the new value.

Overrides:

addValue in class DescriptiveStatistics

Parameters:

v - the value to be added

See Also:

DescriptiveStatistics.addValue(double)

apply

public double apply(UnivariateStatistic stat)

Apply the given statistic to this univariate collection.

Overrides:

apply in class DescriptiveStatistics

Parameters:

stat - the statistic to apply

Returns:

the computed value of the statistic.

clear

public void clear()

Description copied from class: DescriptiveStatistics

Resets all statistics and storage

Overrides:

clear in class DescriptiveStatistics

See Also:

DescriptiveStatistics.clear()

getElement

public double getElement(int index)

Description copied from class: DescriptiveStatistics

Returns the element at the specified index

Overrides:

getElement in class DescriptiveStatistics

Parameters:

index - The Index of the element

Returns:

return the element at the specified index

See Also:

DescriptiveStatistics.getElement(int)

getN

public long getN()

Description copied from class: DescriptiveStatistics

Returns the number of available values

Specified by:

getN in interface StatisticalSummary

Overrides:

getN in class DescriptiveStatistics

Returns:

The number of available values

See Also:

DescriptiveStatistics.getN()

getStandardDeviation

public double getStandardDeviation()

Returns the standard deviation of the available values.

Specified by:

getStandardDeviation in interface StatisticalSummary

Overrides:

getStandardDeviation in class DescriptiveStatistics

Returns:

The standard deviation, Double.NaN if no values have been added or 0.0 for a single value set.

getValues

public double[] getValues()

Description copied from class: DescriptiveStatistics

Returns the current set of values in an array of double primitives. The order of addition is preserved. The returned array is a fresh copy of the underlying data -- i.e., it is not a reference to the stored data.

Overrides:

getValues in class DescriptiveStatistics

Returns:

returns the current set of numbers in the order in which they were added to this set

See Also:

DescriptiveStatistics.getValues()

getWindowSize

public int getWindowSize()

Access the window size.

Overrides:

getWindowSize in class DescriptiveStatistics

Returns:

the current window size.

setWindowSize

public void setWindowSize(int windowSize)

Description copied from class: DescriptiveStatistics

WindowSize controls the number of values which contribute to the reported statistics. For example, if windowSize is set to 3 and the values {1,2,3,4,5} have been added in that order then the available values are {3,4,5} and all reported statistics will be based on these values

Overrides:

setWindowSize in class DescriptiveStatistics

Parameters:

windowSize - sets the size of the window.

See Also:

DescriptiveStatistics.setWindowSize(int)

toString

public java.lang.String toString()

Generates a text report displaying univariate statistics from values that have been added. Each statistic is displayed on a separate line.

Overrides:

toString in class DescriptiveStatistics

Returns:

String with line feeds displaying statistics