public (bool ShirtsInStock, string Status) ServeCustomer(StockController controller)
{
TShirt shirt = controller.SelectRandomShirt();
if (shirt == null)
{
return(false, "All shirts 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}");
}
return(true, null);
}
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);
}