CS 3340 Windows Programming

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

One Barber with one Customer Queue Barber Shop Customer Queue Barber One Barber with one Customer Queue

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

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

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

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

Barber Shop is Open C2 C3 C3 Barber C2 C1

Barber Shop is Open C3 Barber C3 C2

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

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

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

New Customer Comes C5 C6 Barber C4

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

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

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

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

Barber shop can open again Barber Shop Closed Barber shop can open again Barber

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

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

Closing Before Exiting Barber C11

Closing Before Exiting Asking user Yes/No Barber

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

Exiting Before Opening C1 C2 C3 Clear customer queue Barber

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

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

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