public interface MyService extends RemoteService { public String myMethod(String s); }This synchronous interface is the definitive version of your service's specification. Any implementation of this service on the server-side must extend RemoteServiceServlet and implement this service interface.
public class MyServiceImpl extends RemoteServiceServlet implements MyService { public String myMethod(String s) { // Do something interesting with 's' here on the server. return s; } }
interface MyServiceAsync { public void myMethod(String s, AsyncCallback callback); }
The nature of asynchronous method calls requires the caller to pass in a callback object that can be notified when an async call completes, since by definition the caller cannot be blocked until the call completes. For the same reason, async methods do not have return types; they must always return void. After an async call is made, all communication back to the caller is via the passed-in callback object.
The relationship between a service interface and its asynchronous counterpart is straightforward:com.example.cal.client.SpellingService
, then the async
interface must be called
com.example.cal.client.SpellingServiceAsync
. The async
interface must be in the same package and have the same name, but with
the suffix Async
.public ReturnType methodName(ParamType1 param1, ParamType2 param2);an async sibling method should be defined that looks like this:
public void methodName(ParamType1 param1, ParamType2 param2, AsyncCallback callback);