@InterfaceAudience.Public @InterfaceStability.Evolving

# Package org.apache.hadoop.metrics2.lib

A collection of library classes for implementing metrics sources

See: Description

- Class Summary
  Class | Description
  --- | ---
  Interns | Helpers to create interned metrics info.
  MetricsRegistry | An optional metrics registry class for creating and maintaining a collection of MetricsMutables, making writing metrics source easier.
  MutableCounter | The mutable counter (monotonically increasing) metric interface
  MutableCounterInt | A mutable int counter for implementing metrics sources
  MutableCounterLong | A mutable long counter
  MutableGauge | The mutable gauge metric interface
  MutableGaugeInt | A mutable int gauge
  MutableGaugeLong | A mutable long gauge
  MutableMetric | The mutable metric interface
  MutableQuantiles | Watches a stream of long values, maintaining online estimates of specific quantiles with provably low error bounds.
  MutableRate | A convenient mutable metric for throughput measurement
  MutableRates | Helper class to manage a group of mutable rate metrics This class synchronizes all accesses to the metrics it contains, so it should not be used in situations where there is high contention on the metrics.
  MutableRatesWithAggregation | Helper class to manage a group of mutable rate metrics.
  MutableRollingAverages | This class maintains a group of rolling average metrics.
  MutableStat | A mutable metric with stats.

- Enum Summary
  Enum | Description
  --- | ---
  DefaultMetricsSystem | The default metrics system singleton.

## Package org.apache.hadoop.metrics2.lib Description

A collection of library classes for implementing metrics sources

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