Intercepting GWT RequestFactory requests

Question

Is there a way to intercept RequestFactory requests on client side?

I want to intercept calls like this:

dummyRequest.dummyOperation().fire( new Receiver<String>() {
  @Override
  public void onSuccess(String response) {        
  }
});

The idea is to show some loading indication when communicating with server.

Answer 1

You can override the default transport implementation and pass it during RF initialization:

SampleRequestFactory factory = GWT.create( SampleRequestFactory.class );
factory.initialize( new SimpleEventBus(), new DefaultRequestTransport() );

You can inherit from DefaultRequestTransport and override the method

send(String payload, TransportReceiver receiver)

Do some processing before calling the super-implementation and wrap the TransportReceiver with a delegate to handle the result.

Answer 2

final DefaultRequestTransport requestTransport = new DefaultRequestTransport() {
        @Override
        public void send(final String payload, final TransportReceiver receiver) {
            GWT.log("making rpc");
            final TransportReceiver proxy = new TransportReceiver() {
                @Override
                public void onTransportFailure(final ServerFailure failure) {
                    GWT.log("rpc returned");
                    receiver.onTransportFailure(failure);
                }

                @Override
                public void onTransportSuccess(final String payload) {
                    GWT.log("rpc returned");
                    receiver.onTransportSuccess(payload);
                }
            };

            super.send(payload, proxy);

}