public void processStimulus(Enumeration e) {
		WakeupCriterion criterion = (WakeupCriterion) e.nextElement();
		
		boolean collision = false;
		
		if (criterion instanceof WakeupOnCollisionEntry || criterion instanceof WakeupOnCollisionExit) {
			if (criterion instanceof WakeupOnCollisionEntry) {
				collision = true;
			}
			for (Notifiable n: observer) {
				n.update(this, new Boolean(collision));
			}
		}			
				
		wakeupOn(oredCriteria);
	}