The business logic of an enterprise application is probably the most confusing part of the application. By layering the application into presentation, domain and data source layers, we can provide a logical place to put what we call domain logic. It may not always be clear where presentation ends and the domain begins, but that is one of the challenges with building software applications.
In this lecture we look at the domain layer and introduce three domain logic design pattern and one to provide API to the domain.
Video, Part 1: