Good naming schema for Services and DAOs

Question

What is a good naming convention for multi-layered services and DAOs in a multi-tier applications?

In most of our application we have two layers of services, where the top level services use either DAOs or lower-level services for persistence and other tasks.

Both the top-level services and lower-level services end with "Service" in the simple name and the DAOs with "DAO".

Here is an example in UML form. CustomerService is a top-level service, ImageService a lower-level service and CustomerDAO a DAO.

The strict division is necessary in most of our applications because the top level services return DTOs to be used in DWR services or MVC web views. Lower level services do not have such constraints as they are not directly exposed to the View layer in MVC usage.

Also lower level service invocations are sometimes used in open transactions or (Hibernate/JPA) sessions.

What would be a good suffix for the the lower-level services to have them separated from the top-level services?

Answer 1

I don't know if it's the best name, but for the top-level services we use "Worker" as a suffix.