<interface>AlarmListener
+react():void
Door
+react():void+close():void
Voice
+react():void+alarm():void
Sensor
-observers:ArrayList<AlarmListener>
+add(AlarmListener a):void+remove(AlarmListener a):void+sendMessage():void
Security
+react():void+open():void
Test
main():void
Light
+react():void+light():void
