GWT in Action, Second Edition

7.6. Writing the client

We’re almost at the end—only two steps left. As you might expect, we need to write the code that calls the server and receives the result. As we explained earlier, a GWT-RPC call is made asynchronously. And you may have noticed that the service interface that we created for the server side won’t work for an asynchronous call. The reason is that it doesn’t allow for a callback, meaning that there’s no way to handle the result that’s returned at some time after the call is made. We need to start by creating one last interface, which will allow for a callback.

7.6.1. Defining the asynchronous interface

The asynchronous interface is the interface that the client side is coded to. It’s a mirror image of the service interface ...