Event pools

Events are defined in event pools . Each activity has an event pool, which contains the set of events that it recognizes.

The events that an activity recognizes are:
  1. Events that have been defined to it with:
    • DEFINE COMPOSITE EVENT
    • DEFINE INPUT EVENT
    • DEFINE TIMER
    • The EVENT option of the DEFINE ACTIVITY command.
  2. System events.

An event pool of an activity is initialized when the activity is created, and deleted when the activity is deleted. All the event-related commands described in Event-related commands , except FORCE TIMER, operate on the event pool associated with the current activity.

Figure 1 shows an event pool of an activity.
Figure 1. An event pool
The picture shows a rectangle representing an event pool. It contains four atomic events and two composite events. Some of the events are in FIRED state, the others in NOTFIRED state.