The Service Provider Interface for the Metrics API. This package provides an interface allowing a variety of metrics reporting implementations to be plugged in to the Metrics API. Examples of such implementations can be found in the packages `org.apache.hadoop.metrics.file` and `org.apache.hadoop.metrics.ganglia`.

Plugging in an implementation involves writing a concrete subclass of `AbstractMetricsContext`. The subclass should get its configuration information using the `getAttribute(attributeName)` method.