StatusSupport
Consumers of the IAFStatusManager events are typically the adapter service monitors. In some cases it may desirable for an Apama application to have a more generic view of components and their status information so that getting status information will look the same across all components in a system, regardless of component type. For example, in addition to the information provided by the IAFStatusManager such as whether the adapter is up or connected, it may be useful to provide confirmation that the adapter has successfully logged in to an external system or a message that the external system is down.
Apama provides an interface called the StatusSupport event interface to help define this. It allows applications (EPL code) to see state from service monitors such as the adapter service monitors. In order to implement this behavior, adapter authors add code to the adapter service monitors to handle the various StatusSupport events. Developers of Apama applications can then add code to take appropriate actions for the StatusSupport events to their applications that use the adapters. In this way, an application can act as a health monitor and be notified when a component is down or what its status is at any given time.
The StatusSupport events are described in
StatusSupport events.
The StatusSupport event interface is a subscription based interface, so consumers of this information will need to subscribe before receiving status information. The adapter service monitors need to reference count the status subscribers, so they do not stop sending status information if there are any interested consumers left. A subscription will only be removed when the call to remove the last one is made.