Implementing design guidelines
As with the previous chapter, this section provides some general design and best practice guidelines for designing a Domain layer class for a given object. Note that some of these conventions are shared by the Service layer, which also calls the Domain layer because conventions such as bulkification apply to the logic written here as well.
Naming conventions
The key principle of the Domain layer pattern is to lay out the code in such a way that it maps to the business domain of the application. In a Salesforce application, this is typically supported by Custom Objects. As such, it’s important to clearly indicate which Domain layer class relates to which Standard or Custom Object: