The Event Notification Service (ENS) is an alarm dispatcher that detects events on an alarm queue and sends notifications of these events to its subscribers. The ENS API allows programmers to modify publish-and-subscribe functions used by Calendar Server to perform functions such as subscribe to events, unsubscribe to events, and notify a subscriber of events. The ENS APIs consists of these specific APIs: Publisher API, Subscriber API, and Publish and Subscribe Dispatcher API.
For information about the ENS API, see the Sun Java Communications Suite 5 Event Notification Service Guide.
The Calendar Server software also contains support for Java Message Queue for notification, but csnotifyd does not subscribe to it. Thus, it is not part of the default alarms and notification system. For more information, refer to the Sun Java System Java Message Queue documentation.