Consider the following function:

public IVehicleProcessor GetVehicle(VehicleType vehicleType, string regNo) {

    if (vehicleType == VehicleType.Car)
        return new CarProcessor(regNo);

    if (vehicleType == VehicleType.Van)
        return new VanProcessor(regNo);

    if (vehicleType == VehicleType.Truck)
        return new TruckProcessor(regNo);

    // the list goes on.

    return null;
}

And then in another (“child”) project

public enum VehicleType {
    Car,
    Van,
    Truck,
    // etc.
}

Is there a way of re-writing this method so that it doesn’t rely on a bunch of if statements? (And I don’t mean by just changing it to a switch). This code will be customised a bit, and let’s say I wanted to add, say, a Bus, I’d like to be able to just create a BusProcessor : IVehicleProcessor and add Bus to the VehicleType enum and GetVehicle() would just know what to do. Perhaps using Reflection or something?

For example, I was thinking maybe having the VehicleType as a property in IVehicleProcessor such that each ‘processor’ class would return its own Vehicle type, but I don’t know how I could access that from GetVehicle() – especially as it would have to be done before it’s instantiated. Could also make it a static property, but then how to enforce that using the IVehicleProcessor interface?