Figure 2

MVC architecture of CReST. Each module has a ConcreteModuleRunner object that extends the AbstractModuleRunner class. The AbstractModuleRunner implements the Observer interface and uses the method Observer.update() to view each new timestamped Event popped from the time-sorted EventQueue. The ConcreteModuleRunner then chooses to ignore or react to the Event, which may cause future Events to be generated and added to the EventQueue.