1. CS 3340 Windows Programming

2. Test 3: Threading Barbershop Similar to Prog5 (Reader & Writer)
Tuesday, April 4
Lab 206
80 minutes
Initial solution

3. One Barber with one Customer Queue
Barber Shop
Customer Queue
Barber
One Barber with one Customer Queue

4. The queue could be empty
Before Opening
Barber
The queue could be empty

5. Barber goes to sleep if the Barber shop opens with an empty queue

6. There may be customers waiting in the queue
Before Opening C1 C2 C3
Barber
There may be customers waiting in the queue

7. Barber Shop Opens Barber removes customer from the queue Barber
Barber wakes up customer after the hair cut

8. Barber Shop is Open C2 C3 C3
Barber C2 C1

9. Barber Shop is Open C3
Barber C3 C2

10. Barber goes to sleep when the queue is empty
Barber Shop is Open
Barber
Barber goes to sleep when the queue is empty

11. New Customer Comes when the Barber is Sleeping
Customer enters queue,
wakes up barber,
Then goes to sleep.
Barber

12. New Customer Comes when the Barber is Sleeping
Barber will remove customer from the queue.
Barber C4

13. New Customer Comes C5 C6
Barber C4

14. Barber should finish all waiting customers
Barber Shop Closing C5 C6
Barber should finish all waiting customers
Barber C4

15. New customers don’t wait when shop is closing
Barber Shop Closing C7 C5 C6
New customers don’t wait when shop is closing
Barber C4

16. New customers don’t wait when shop is closing
Barber Shop Closing C8 C6
New customers don’t wait when shop is closing
Barber C5

17. New customers don’t wait when shop is closing
Barber Shop Closing C9
New customers don’t wait when shop is closing
Barber C6

18. Barber shop can open again
Barber Shop Closed
Barber shop can open again
Barber

19. New customers wait when shop is closed
Barber Shop Closed
C10
C11
New customers wait when shop is closed
Barber

20. Barber Shop Opens Barber removes customer from the queue Barber
Barber wakes up customer after the hair cut

21. Closing Before Exiting
Barber
C11

22. Closing Before Exiting
Asking user Yes/No
Barber

23. Customers come and wait
User No C1 C2 C3
Customers come and wait
Barber

24. Exiting Before OpeningC1 C2 C3
Clear customer queue
Barber

25. Barber Thread Creating a new thread when the Barber shop opens
The thread will be terminated when the Shop closed
When the Shop opens again, a new thread is created
The run sub of the Barber class is for one iteration of Open-Close to make code simpler

26. Prog5
‘ Waits for all readers and writers to finish the work in order to ‘ terminate the program. ‘ Mutual exclusion on the DataObj and the queue must be enforced. Public Shared Sub FinishReadWrite() _database.LockDataObj() Monitor.Enter(FIFOQueue) If FIFOQueue.Count > 0 or _database.TheDatabaseStatus <> DataBaseClass.DatabaseStatus.Empty Then endProgram.Reset() Else endProgram.Set() End If Monitor.Exit(FIFOQueue) _database.ReleaseDataObj() endProgram.WaitOne() ‘do not know which thread will wake it up End Sub

27. JOIN Method
Public Sub CloseBarberShop() Monitor.Enter(BarberShopClass.TheBarberStateObj) BarberShopClass.theBarberState = BarberShopClass.BarberState.Closing Monitor.Exit(BarberShopClass.TheBarberStateObj) barberEvent.Set() ‘ Wait until _barberThread is terminated _barberThread.Join() End Sub