_______________________________________________________
	|			Elevator			|
	|_______________________________________________________|
	|							|
    	|  + final boolean  UP = true				|
    	|  + final boolean DOWN = false				|
        |  + final boolean ON = true				|
        |  + final boolean OFF = false				|
        |  + final boolean OPEN = true				|
    	|  + final boolean CLOSED = false			|
	|							|
     	|  - boolean direction      				|
	|  - int currentFloor					|
    	|  - boolean doorStatus					|
    	|  - boolean[]  floorButtonInElevator			|
    	|  - boolean emergencyStopButton			|
    	|  - boolean operative					|
    	|  - boolean returnToGround				|
	|  - double capacityWt					\
	|  - doubel currentWt					|
    	|  - int  MaximumFloorNumber,MinimumFloorNumber		|
	|_______________________________________________________|
	| <constructor>						|
	|   + Elevator (int,int)				|
	| <query methods>					|		
	|   + int getCurrentFloor()				|
	|   + boolean getDoorStatus()				|
	|   + boolean getEmergencyStopButton()			|
	|   + boolean getDirection()				|
	|   + boolean getOperative()  				|
	|   + boolean getReturnToGround()  			|
	|   + double  getCurrentWt()				|
	| <update methods>					|		
	|   + void changeFloor()				|
	|   + void openDoor()					|
	|   + void closeDoor()					|
	|   + void setFloorButton(int)				|
	|   + void setEmergencyStopButton(boolean )		|
	|   + void haltElevator()				|
	|   + void enterElevator(double)			|
	|   + double exitElevator()				|
	|   + void setOperative(boolean)			|
	|   + void returnToGroundFloor()			|
	|_______________________________________________________|