Organize objects in a BLL

Question

What is the most common way to organize objects in a Business Object Layer?

For Example, I've worked with a BLL with that took this approach:

• Common Folder - contains static utility files
• Interfaces Folder - All Interfaces
• Dal - Data Access Objects
• Services - Objects that access Services
• Project Root - Contains the business objects

I've also seen Interfaces mixed in business objects, and BLL projects that have objects in model and Library folders.

Answer 1

It is far better to arrange them in logical groups though. Your Business logic might have many sections and file pertaining to a specific section should be in the same section.

e.g. say Discounts, you might have a service which can calculate discounts, at the same time you might have objects which yield discount information. It would be better to put all of them in one folder.