Class SampledStat

All Implemented Interfaces:
Measurable, MeasurableStat, MetricValueProvider<Double>, Stat
Direct Known Subclasses:
Avg, Frequencies, Max, Min, Percentiles, WindowedSum

public abstract class SampledStat extends Object implements MeasurableStat
A SampledStat records a single scalar value measured over one or more samples. Each sample is recorded over a configurable window. The window can be defined by number of events or elapsed time (or both, if both are given the window is complete when either the event count or elapsed time criterion is met).

All the samples are combined to produce the measurement. When a window is complete the oldest sample is cleared and recycled to begin recording the next sample. Subclasses of this class define different statistics measured using this basic pattern.

  • Field Details

  • Constructor Details

    • SampledStat

      public SampledStat(double initialValue)
  • Method Details

    • record

      public void record(MetricConfig config, double value, long timeMs)
      Description copied from interface: Stat
      Record the given value
      Specified by:
      record in interface Stat
      config - The configuration to use for this metric
      value - The value to record
      timeMs - The POSIX time in milliseconds this value occurred
    • newSample

      protected SampledStat.Sample newSample(long timeMs)
    • measure

      public double measure(MetricConfig config, long now)
      Description copied from interface: Measurable
      Measure this quantity and return the result as a double
      Specified by:
      measure in interface Measurable
      config - The configuration for this metric
      now - The POSIX time in milliseconds the measurement is being taken
      The measured value
    • current

      public SampledStat.Sample current(long timeMs)
    • oldest

      public SampledStat.Sample oldest(long now)
    • toString

      public String toString()
      toString in class Object
    • update

      protected abstract void update(SampledStat.Sample sample, MetricConfig config, double value, long timeMs)
    • combine

      public abstract double combine(List<SampledStat.Sample> samples, MetricConfig config, long now)
    • purgeObsoleteSamples

      protected void purgeObsoleteSamples(MetricConfig config, long now)