org.flexiblepower.observation

Interface ObservationProvider<T>

Type Parameters:

T - The type of value that will be in the published observations.

All Known Implementing Classes:

AbstractObservationProvider, SimpleObservationProvider

public interface ObservationProvider<T>

The ObservationProvider is any object that wants to publish Observations to a ObservationConsumer. When using OSGi, there are a couple of properties that should be registered to make it easier for consumers to find the proper providers.

• org.flexiblepower.monitoring.observedBy: describes the component that does the observations. Normally this will be the name of the component itself.
• org.flexiblepower.monitoring.observationOf: describes the physical thing that it is observing.
• org.flexiblepower.monitoring.type: gives the full classname of the type of value that will be published by the provider.
• org.flexiblepower.monitoring.type.X: for each attribute, the X is replaced by the name of the attribute (as will be returned by the method and the value is the type description, usually the classname.
• org.flexiblepower.monitoring.type.X.unit: optionally describes the unit in which the attribute will be transformed. This is only relevant for raw values, like doubles or integers.
• org.flexiblepower.monitoring.type.X.optional: optionally describes if an attribute is optional. By default the consumer may assume that all attributes are available each time, but by setting this to true it can indicate otherwise.

Method Summary

Methods

Modifier and Type	Method and Description
Observation<? extends T>	getLastObservation() Get the last published Observation.
void	subscribe(ObservationConsumer<? super T> consumer) Binds the consumer to this provider.
void	unsubscribe(ObservationConsumer<? super T> consumer) Unbinds the consumer from this provider.

Method Detail

subscribe

void subscribe(ObservationConsumer<? super T> consumer)

Binds the consumer to this provider. After this call has returned, all the observations produced by the provider should be sent to this consumer via its ObservationConsumer.consume(ObservationProvider, Observation) method.

Parameters:

consumer - The ObservationConsumer that will be bound to this provider.

unsubscribe

void unsubscribe(ObservationConsumer<? super T> consumer)

Unbinds the consumer from this provider. After this call has returned, the observations must no longer be sent to the consumer.

Parameters:

consumer - The ObservationConsumer that will be unbound from this provider.

getLastObservation

Observation<? extends T> getLastObservation()

Get the last published Observation.

Returns:

The last published observation, or null when no observation has been published yet.