This package defines the event classes for the AOCS Framework. The Framework recognizes several types of events which are all derived from the AocsEvent class. This class is itself derived from the EventObject class. Each category of events has its own dedicated event class. The framework predefines several types of event classes. Others may be defined by specific applications. The framework event model complies with the JavaBeans event model. There are however some differences in the way the events are used due to the fact the framework does not allow dynamic creation of objects during normal operation.

Consider for instance the case of an event source that needs to fire an event of type EventType to its event listeners. The source component maintains a statically defined instance of EventType. Just before firing the event, rather than creating a new event representing the event to be fired (as is the case in ordinary JavaBeans applications), the source components loads the statically defined event with the parameters defining the event to be fired and passes this event to the fireEvent method. The event listeners will then copy the parameters of the fired event into some internal storage and will then release the fired event. In this way, the source component can use the same EventType instance for all event firings without needing to create new instances dynamically.

As a consequence of the above, the parameters of the framework events must be settable. This is why the source field in EventObject is not used and is assigned to a dummy instance of Object at event creation.

Event handling is described in the Intercomponent Communication Framelet document but note that this document was originally written for the C++ version of the framework and hence it is not applicable in its entirety.