18/5 - 2007 1
VIP Elevator – second model
A VDM++ Project
Made By: Sune Wolff
18/5 - 2007 2
Agenda
Summary of First Model Desired Improvements Class Diagram Mapping Intelligent Elevator Intelligent Queue Achieved Improvements
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Summary of First Model
Basic first model FIFO queue for placing orders
Using ordered sequence of floors Elevator moved between floors in
atomic fashion
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Desired Improvements
Introduce classes for buttons and sensors Make use of mapping
Make elevator more intelligent Keep track of direction Choose next floor based on direction and distance
Introduce automatic test Read test sequence from file
Make sure the VIP receives special treatment No neighbours in elevator when VIP wants to use it Execute VIP order as soon as possible
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Class DiagramWorld
Run()World()
Environment
Environment()
-environment
Elevator
VipExit()VipEnter()Elevator()MoveElevator()NeighbourExit()NeighbourEnter()ActivateSensor()PushOuterButton()UpdateCurrent()PushInnerButton()UpdateDir()
Queue
Queue()QueueFull()QueueEmpty()PutInQueue()GetNextFromQueue()
EC
EC()
-ec
+$elevator
+$vipQueue
+$innerQueue
+$outerQueue
Turnstile
locked : bool
Turnstile()LockTurnstile()UnlockTurnstile()IsTurnstileLocked()
+$tsController
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Mapping
class ECinstance variables public static floorMap : map Elevator`Floor to nat :=
{<none> |-> -1, <ground> |-> 0, <one> |-> 1, <two> |-> 2, <three> |-> 3, <penthouse> |->
4}; public static invFloorMap : map nat to Elevator`Floor := inverse floorMap;end EC
class Elevatoroperations public UpdateCurrent: Dir * Floor ==> Floor UpdateCurrent(dir, cur) == (dcl curNum : nat := EC`floorMap(cur); if (dir = <up> and cur <> <penthouse>) then curNum := curNum + 1 elseif (dir = <down> and cur <> <ground>) then curNum := curNum – 1; return EC`invFloorMap (curNum); );end Elevator
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Intelligent Elevator
public MoveElevator: () ==> Floor MoveElevator() == (if (not EC`vipQueue.QueueEmpty() and EC`innerQueue.QueueEmpty()) then (nextFloor := EC`vipQueue.GetNextFromQueue(direction, currentFloor, nextFloor); currentFloor := UpdateCurrent(direction, currentFloor); return nextFloor) elseif (not EC`innerQueue.QueueEmpty()) then (nextFloor := EC`innerQueue.GetNextFromQueue(direction, currentFloor, nextFloor); currentFloor := UpdateCurrent(direction, currentFloor); return nextFloor) elseif (not EC`outerQueue.QueueEmpty()) then (nextFloor := EC`outerQueue.GetNextFromQueue(direction, currentFloor, nextFloor); currentFloor := UpdateCurrent(direction, currentFloor); return nextFloor) else (UpdateDir(direction); return <none>;
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Intelligent Queue
public GetNextFromQueue: Elevator`Dir * Elevator`Floor * Elevator`Floor ==> [Elevator`Floor]
GetNextFromQueue(dir, cur, next) == (dcl nextFloor : Elevator`Floor := next; dcl nextSet : set of Elevator`Floor := {}; dcl top : Elevator`Floor := <penthouse>; dcl bottom : Elevator`Floor := <ground>; for all f in set elevatorQueue do (if (dir = <up> and EC`floorMap(f) > EC`floorMap(cur)) then (nextSet := nextSet union {f}; for all nextF in set nextSet do (if (next = <none>) then (if (EC`floorMap(nextF) < EC`floorMap(top)) then (nextFloor := nextF; top := nextF;) elseif (EC`floorMap(nextF) < EC`floorMap(nextFloor)) then nextFloor := nextF;
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Intelligent Queue #2
if (nextFloor <> next and next <> <none>)then (elevatorQueue := elevatorQueue union {next}; elevatorQueue := {y | y in set elevatorQueue & y <> nextFloor};
)elseif (next = <none>)then elevatorQueue := {y | y in set elevatorQueue & y <> nextFloor};return nextFloor;
18/5 - 2007 10
Achieved Improvements
Introduce classes for buttons and sensors Make use of mapping
Make elevator more intelligent Keep track of direction Choose next floor based on direction and distance
Introduce automatic test Read test sequence from file
Make sure the VIP receives special treatment No neighbours in elevator when VIP wants to use it Execute VIP order as soon as possible
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VDMUnit