org.rhq.core.pluginapi.measurement
Interface MeasurementFacet

public interface MeasurementFacet

Implementations of this facet perform the collection of measurement data exposed by a managed resource.

Method Summary

void	getValues(MeasurementReport report, Set<MeasurementScheduleRequest> metrics) Collects measurement data exposed by managed resources and returns that data in a measurement report. the provided set of requests specify which metrics are being requested.

Method Detail

getValues

void getValues(MeasurementReport report,
               Set<MeasurementScheduleRequest> metrics)
               throws Exception

Collects measurement data exposed by managed resources and returns that data in a measurement report. the provided set of requests specify which metrics are being requested. All collected data should be added to the provided report.

If there is no data available for one of the requested metrics, there are several ways an implementation of this method can indicate that:

1. do not add a datum to the report
2. add a datum with a value of null to the report
3. if it's a numeric metric, add a datum with a value of Double.NaN to the report

The key to the improvement in metric collection performance and reduction in monitoring overhead is to take advantage of the situations where a single remote call can return more than one piece of data; e.g. a JMX MBean getAttributes call, or a database SELECT.

Parameters:

report - the report to which all collected measurement data should be added

metrics - a set of requests describing the metrics being requested

Throws:

Exception - if the component failed to obtain one or more values