Create an IUserType for a generic option class with nhibernate

Question

I'm looking for a way to create an IUserType for an option type class. Here is the option type class code:

public static class Option 
{
    public static Option<T> Some<T>(T value)
    {
        return new Option<T>(value);
    }

    public static Option<T> None<T>()
    {
        return new Option<T>();
    }
}
public class Option<T>
{
    public Option(T value)
    {
        _value = value;
        _isSome = true;
    }

    public Option()
    {
        _isSome = false;
    }

    T _value;
    bool _isSome;

    public bool IsSome
    {
        get { return _isSome; }
    }

    public bool IsNone
    {
        get { return !_isSome; }
    }

    public T Value
    {
        get { return _value; }
    }

    public T ValueOrDefault(T value)
    {
        if (IsSome)
            return Value;

        return value;
    }

    public override bool Equals(object obj)
    {
        var temp = obj as Option<T>;
        if (temp == null)
            return false;

        if (this.IsNone && temp.IsNone)
            return true;

        if (this.IsSome && temp.IsSome)
        {
            var item1 = this.Value;
            var item2 = temp.Value;
            return object.Equals(item1, item2);
        }

        return false;
    }

    public override int GetHashCode()
    {
        if (this.IsNone)
            return base.GetHashCode() + 23;

        return base.GetHashCode() + this.Value.GetHashCode() + 23;
    }
}

It is basically just a wrapper around whatever type of T the user wants. It should end up mapping a nullable version of T. I have been unable to find any documentation on doing something like this.

Any help is appreciated.

Answer 1

Here are some articles I have used for the basis of my IUserType classes:

• Implementing Custom Types in NHibernate
• Generic NHibernate User Type Base Class
• Implementing Money Type NHibernate