The Runtime Model API

Service Performance Manager also exposes certain runtime model elements. This provides the ability to introduce user-defined or custom metric functions and custom actions.

MetricNode
 MetricNode is a node that holds metric values.
RtaNodeContext
  RtaNodeContext is a container for name/value tuples. It stores stateful data for the metric calculation. It is required to optimize metric calculations so that it does not iterate over child metric or Facts each time there is a new Fact submitted.
MetricFunction 
This interface must be implemented to define a custom metric aggregator function.
ActionHandlerContext
  This interface must be implemented for one-time context initialization while developing custom actions.