// Value type describing what happened on the device.
@class JSDeviceEvent;

// Protocol implemented by objects interested in being notified when a device event happens.
@protocol JSDeviceEventObserver

- (void)observeDeviceEvent:(JSDeviceEvent *);

@end

// Object that actually listens for device events and tells interested observers about them.
@interface JSDeviceEventController

- (void)addEventObserver:(id<JSDeviceEventObserver>)eventObserver;
- (void)removeEventObserver:(id<JSDeviceEventObserver>)eventObserver;

@end