What’s the best way to design a Java server architecture that interacts with a client-side GWT application, but also responds correctly to various other client-requests from other platforms? Specifically, I’d like to use the same servlet layer to respond to not only my GWT application, but to corresponding iOS and Android applications.
The first approach I thought of would be to implement the GWT client layer using “RequestBuilder” rather than the usual RPC method service interfaces. Using this approach, I could code generic servlets that respond to HTTP requests in a RESTful manner by processing variables encoded in something like JSON or XML. Although this would work, it would be somewhat labor-intensive to have to encode and decode my objects/parameters in JSON on both the client and server, especially when RPC provided such an elegant solution.
The other approach (which I think is better), would be to find out the specification Google uses to serialize and deserialize their RPC method calls and implement some sort of library that does the same thing for iOS (in Objective-C) and Android. The problem is that I haven’t been able to find good documentation about this encoding standard, nor have I found libraries that implement it for iOS or Android (although I did find something like it for PHP at http://www.gwtphp.com).
Could anybody steer me toward a specification for how GWT serializes/deserializes their objects or, even better, libraries for iOS and/or Android that implement RPC interfaces?
Make a “service” layer, i.e. a set of business classes that return POJOs.
Then you can easily have GWT-RPC and REST calling the service layer.
This is pretty easy and straightforward. Your issue is going to be how to create a business layer that only returns POJOs. But that’s another story.