public void AcceptPayment(decimal amount)
{
/*
* In this example we inherit the same interface as the original BillingProcessor class
* which enables our clients to use our Proxy in place of the original class. But, with this
* proxy we apply some protection logic to prevent payments to be made with negative amount and
* allow payments to be made with MasterCard only.
*/
if (amount < 0)
{
throw new Exception("You can not make negative payments.");
}
if (_paymentMethod != PaymentMethod.MasterCard)
{
throw new Exception($"Your payment method {_paymentMethod} is not supported");
}
_processor.AcceptPayment(amount);
}