public void Work(TimeSpan workDay, StockController_WithConcurrent controller)
{
DateTime start = DateTime.Now;
while (DateTime.Now - start < workDay)
{
var result = ServeCustomer(controller);
if (result.Status != null)
{
Console.WriteLine($"{Name}: {result.Status}");
}
if (!result.ShirtsInStock)
{
break;
}
}
}
public static void Run()
{
//StockController controller = new StockController(TShirtProvider.AllShirts);
//TimeSpan workDay = new TimeSpan(0, 0, 0, 0, 500);//500ms
//new SalesPerson("Jack").Work(workDay, controller);
//new SalesPerson("Anna").Work(workDay, controller);
//new SalesPerson("Mike").Work(workDay, controller);
//controller.DisplayStock();
//CONCURRENT
StockController_WithConcurrent controller = new StockController_WithConcurrent(TShirtProvider.AllShirts);
TimeSpan workDay = new TimeSpan(0, 0, 0, 0, 500);//500ms
new SalesPerson_WithConcurrent("Jack").Work(workDay, controller);
new SalesPerson_WithConcurrent("Anna").Work(workDay, controller);
new SalesPerson_WithConcurrent("Mike").Work(workDay, controller);
controller.DisplayStock();
//Use TryGetValue(),TryRemove() in CONCURRENT otherwise this makes same shits sold by multiple salespersons.
//In Any Concurrent Colections:
//The Collection might not contain the values you are expecting even if you only checked that collection a moment ago.It could still change If other threads are accessing.modifying them.
//Always use TryXXX() methods which don't presume knowledge of state
}
public (bool ShirtsInStock, string Status) ServeCustomer(StockController_WithConcurrent controller)
{
//TShirt shirt = controller.SelectRandomShirt();
(SelectResult Result, TShirt shirt)result = controller.SelectRandomShirt();
TShirt shirt = result.shirt;
//if (shirt == null)
if (result.Result == SelectResult.NoStockLeft)
{
return(false, "All shirts sold");
}
else if (result.Result == SelectResult.ChosenShirtSold)
{
return(true, "Can't show shirt to customer-already sold");
}
Thread.Sleep(Rnd.NextInt(30));
// customer chooses to buy with only 20% probability
if (Rnd.TrueWithProb(0.2))
{
//controller.Sell(shirt.Code);
//return (true, $"Sold {shirt.Name}");
bool sold = controller.Sell(shirt.Code); //here, you assume that you can sell the shirt, because a few millisecs ago you looked in _stock concurrantDictionary.But by the time code reaches this line, another thread might have sold it.
//so, use TryRemove() inside sell.
if (sold)
{
return(true, $"Sold {shirt.Name}");
}
else
{
return(true, $"Can't sell {shirt.Name}: Already Sold"); //sold by another thread
}
}
return(true, null);
}
