Question

Lots of frameworks let me expose an ejb as a webservice.

But then 2 months after publishing the initial service I need to change the ejb or any part of its interface. I still have clients that need to access the old interface, so I obviously need to have 2 webservices with different signatures.

Anyone have any suggestions on how I can do this, preferably letting the framework do the grunt work of creating wrappers and copying logic (unless there’s an even smarter way).

I can choose webservice framework on basis of this, so suggestions are welcome.

Edit: I know my change is going to break compatibility,and I am fully aware that I will need two services with different namespaces at the same time. But how can I do it in a simple manner ?

Answer 1

I don’t think, you need any additional frameworks to do this. Java EE lets you directly expose the EJB as a web service (since EJB 2.1; see example for J2EE 1.4), but with EE 5 it’s even simpler:

@WebService @SOAPBinding(style = Style.RPC) public interface ILegacyService extends IOtherLegacyService {     // the interface methods     ... }  @Stateless @Local(ILegacyService.class) @WebService(endpointInterface = '...ILegacyService', ...) public class LegacyServiceImpl implements ILegacyService {     // implementation of ILegacyService } 

Depending on your application server, you should be able to provide ILegacyService at any location that fits. As jezell said, you should try to put changes that do not change the contract directly into this interface. If you have additional changes, you may just provide another implementation with a different interface. Common logic can be pulled up into a superclass of LegacyServiceImpl.