Cannot use generics in Errai RPC

[fvitorc]

Hi,

Errai cannot handle generic methods. If I declare a remote service as:

<A extends Action<R>, R extends ActionResult> R execute(A action)

The RPCStub generated by Errai is:

public ActionResult execute(Action _0)

Then the GWT compiler fails with:

[ERROR] Errors in 'generated://786F5E4D45EAB85B5D2D81DBDE4686F4/org/jboss/errai/bus/client/ext/ExtensionsLoaderImpl.java'

   [ERROR] Line 56:  The type DispatchServiceImpl must implement the inherited abstract method DispatchService.execute(A)

   [ERROR] Line 80:  Name clash: The method execute(Action) of type DispatchServiceImpl has the same erasure as execute(A) of type DispatchService but does not override it

I believe that there is no solution to that, but maybe my knowledge of generics is not so good.

Does anyone know if it is possible to solve this problem?

Regards,

Vitor.

[csa]

You're right. Generics are currently not supported in Errai RPC. I have created a feature request for it: https://issues.jboss.org/browse/ERRAI-148

[superfis]

In simple usage it seems to work correctly...

That's my working example:

remote service

...

public List<UserDTOFull> getUsers( ) {

...

}

RPC call

MessageBuilder.createCall( new RemoteCallback<List<UserDTOFull>>( ) {

            @Override

            public void callback( List<UserDTOFull> response ) {

                ...

            }

          }, UsersRPCService.class ).getUsers( );

[csa]

Yes, this is because the type parameter (UserDTOFull) is a custom type using @ExposeEntity. It wouldn't work for lets say List<Long>. However, we are working on supporting this soon.

[superfis]

Thank you for the explanation.

Do you plan to support Generics in 1.3.0-SNAPSHOT or 2.0-SNAPSHOT?

[fvitorc]

The reason I started this thread was that I was having problems with generic methods, not generic types:

http://download.oracle.com/javase/tutorial/extra/generics/methods.html

[csa]

You can watch https://issues.jboss.org/browse/ERRAI-148 to track the progress on this. It's scheduled for Errai 2.0.

[navigateur]

Are you saying I won't be able to transport a simple ArrayList<Integer> until version 2.0, or is that already possible? If not possible right now, what could possibly be more urgent?