Good point.

You could certainly do that, though if the decision point remains in code you would just be moving the case statement to another location. Instead of determining the strategy within the Process function, the strategy would have to be created somewhere within the code that creates the PaymentRequest.

Since we’re adding a new class, we have to specify somewhere, either in code or via configuration, the link between a particular request and its strategy.

In this case we could create a mapping table that links a PaymentTypeId to a strategy class name, in which case we could just use the class name to create an instance of the strategy to use.

That has the benefit of being more configuration-based, and as such it would let you change what strategy to use for each payment type on the fly.

David Cooksey

private void Process(IPaymentRequest request)
{
IPaymentStrategy strategy = request.paymentStrategy;

double amount = strategy.CalculateAmount(request);
WriteCheck(amount);

}

or something similar?

thanks again!

Tyler Madison