## org.apache.hadoop.metrics2.util
Class SampleStat

    java.lang.Object
      org.apache.hadoop.metrics2.util.SampleStat

    public class SampleStat

extends Object

Helper to compute running sample stats

Nested Class Summary
`static class` `SampleStat.MinMax` Helper to keep running min/max

Constructor Summary
`SampleStat()` Construct a new running sample stat

Method Summary
`SampleStat` `add(double x)` Add a sample the running stat.
`SampleStat` `add(long nSamples, double x)` Add some sample and a partial sum to the running stat.
`void` `copyTo(SampleStat other)` Copy the values to other (saves object creation and gc.)
`double` `max()`
`double` `mean()`
`double` `min()`
`long` `numSamples()`
`void` `reset()`
`double` `stddev()`
`double` `variance()`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### SampleStat

    public SampleStat()

  Construct a new running sample stat

Method Detail

### reset

    public void reset()

### copyTo

    public void copyTo(SampleStat other)

  Copy the values to other (saves object creation and gc.)

  Parameters:
    `other` - the destination to hold our values

### add

    public SampleStat add(double x)

  Add a sample the running stat.

  Parameters:
    `x` - the sample number
  Returns:
    self

### add

    public SampleStat add(long nSamples,
                          double x)

  Add some sample and a partial sum to the running stat. Note, min/max is not evaluated using this method.

  Parameters:
    `nSamples` - number of samples
    `x` - the partial sum
  Returns:
    self

### numSamples

    public long numSamples()

  Returns:
    the total number of samples

### mean

    public double mean()

  Returns:
    the arithmetic mean of the samples

### variance

    public double variance()

  Returns:
    the variance of the samples

### stddev

    public double stddev()

  Returns:
    the standard deviation of the samples

### min

    public double min()

  Returns:
    the minimum value of the samples

### max

    public double max()

  Returns:
    the maximum value of the samples

Copyright © 2009 The Apache Software Foundation