::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: This class provides casual links between events.
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: This class represents a single simulation entity for event-scheduling simulation.
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: This class provides facilities for defining simulation events.
This class schedules events and implements the time advance mechanism for simulation model following the event-scheduling world view.
This object is used to test the Model class.