Question

This link is a paper detailing “Product Trader Pattern”

Does anyone have some experiences to share with this? Links to some example code?

I’d love to see some implementation examples in C# in particular.

Two issues are confusing me:
(1) the creation of a product. can someone translate the example code in the paper (below) into c#
(2) is the specification class the same as the Specification Pattern advocated by Evans and Fowler?

Cheers,
Berryl

template<class ProductType, class SpecType>
class Creator
{
    public:
        Creator(SpecType aSpec) : _aSpecification(aSpec) {}
        SpecType getSpecification() { return _aSpecification; }
        ProductType * create() = 0; 
    private:
        SpecType _aSpecification;
};

template<class ProductType, class ConcreteProductType, class SpecType>
class ConcreteCreator : public Creator<ProductType, SpecType>
{
    public:
        ConcreteCreator(SpecType aSpec) : Creator<ProductType, SpecType>(aSpec) {}
        ProductType * create() { return new ConcreteProductType; }
}

Answer 1

Here is a translation of the code in C#:

public abstract class Creator<ProductType, SpecType>
{
    public Creator(SpecType aSpec) { _aSpecification = aSpec; }

    public SpecType GetSpecification() { return _aSpecification; }

    public abstract ProductType Create();

    private SpecType _aSpecification;
}

public class ConcreteCreator<ProductType, ConcreteProductType, SpecType> : Creator<ProductType, SpecType> where ConcreteProductType : ProductType, new()
{
    public ConcreteCreator(SpecType aSpec) : base(aSpec) { }

    public override ProductType Create() { return new ConcreteProductType(); }
}