Question

I’m trying to figure out how all these work together. I know that a DTO is basically just a container of data for the Domain Objects to pass back and forth to forms and such. Does the Domain object contain a DTO or do the DTO and the Domain Object happen to just have all of the same properties that will be mapped manually?

If I am exposing my DTO type in a service, how do I use the getters and setters without creating a round trip for each get/set operation on the client? I know that you can have one long constructor, but that can get ugly if you have more than 7 properties.

When implementing the Repository pattern, do I pass in the DTO or the Domain Object?

Answer 1

• The DTO’s and the Domain objects should be separate.
• There should be a mapper that maps a DTO to a domain object and a domain object to a DTO. This mapper should be an implementation of an interface, with the default mapper using reflection to map the objects to each other.
• The repository should be a service that returns the domain objects, which themselves should services.
• If the DTO is a class that is exposed by a web service, the WSDL that is created defines the property as an element, and the proxy that gets created on the other side just creates a getter / setter property that is run on the client itself, so the getters and setters do not cause a roundtrip.
• Even if you just create a public variable in your DTO, the proxy will be implemented as a getter and setter.