GWT RequestFactory and multiple types

My GWT app has ten different kinds of entities. Right now I use plain old DTOs and transport them over GWT-RPC. This works well for cases like startup - I can pack them all into a single request.

I'm looking at switching to RequestFactory because there are many times throughout the lifetime of the app (30 minutes, on average) when I just have to update one type of entity, and the unifying/bandwidth-saving features of RequestFactory are appealing. BUT: I don't see a way to download all of my initialization data in a single request when the app loads. I don't want to have to make ten requests to fetch all of the init data for my ten entity types.

Is there a way to make a GeneralRequestContext, or something? I'd even be happy with a solution like:

public interface InitDataProxy extends EntityProxy
{
    public UserProxy getInitUsers();
    public OrganizationProxy getInitOrganizations();
    ...
}

public interface GeneralRequestContext extends RequestContext
{
    Request<InitDataProxy> getInitData();
}

But this won't work because I don't want to have to actually back InitDataProxy with anything, I just want to use it to combine a bunch of different types of Proxies in a single request.

So: Is there a way to receive multiple, unrelated types of EntityProxy in a single request?

I would also be happy enough making a normal gwt-rpc request to go outside of RequestFactory for this data, but I don't want to have to implement duplicate DTOs to run next to RequestFactory开发者_开发问答's proxies, and write custom code to copy the DTOs into them!

The InitDataProxy could extend ValueProxy instead, which doesn't require that the object on the server have any kind of id or version semantics. The domain-side InitData type could be an interface, possibly implemented with an anonymous type.

interface InitData {
  User getUser();
  Organization getOrgatization();
}
class InitService {
  static InitData makeInitData() {
    return new InitData() { ..... };
  }
}

@ProxyFor(InitData.class)
interface InitDataProxy extends ValueProxy {
  UserProxy getUser();
  OrganizationProxy getOrganization();
}
@Service(InitService.class)
interface Init extends RequestContext {
  Request<InitDataProxy> makeInitData();
}