what I need is a pattern to resolve the problem (maybe it's not a problem), it's a part of a project, it's dependent of any platform.
the customer has specification, but don't care about it, you can implement it in the derived class, it's not related with the pattern, I guess you didn't read books about design pattern
the customer has specification, but don't care about it, you can implement it in the derived class, it's not related with the pattern, I guess you didn't read books about design pattern