Error override

Question

I wrapped my updated code in the class as shown below. If this is not clear from the code, I submit it by interacting with the calming service with OAuth.

What would be a good way to handle errors? The REST server returns an error message in json format. I would like to act on this post by throwing some exceptions from my class. I am trying to do something like below. But is this a good design? Does callbacks and exception mix, throwing a good idea? Is there a better way?

With the approach below, I could receive i18l messages from my user exceptions and push them towards the user.

public class RestClient implements IRestClient {
    private IRestAPI api;

    /**
     *
     * @param accessToken
     */
    public RestClient(final String accessToken)
    {
        RequestInterceptor requestInterceptor = new RequestInterceptor()
        {
            @Override
            public void intercept(RequestFacade request) {
                request.addHeader("Authorization", "Bearer " + accessToken);
            }
        };

        RestAdapter restAdapter = new RestAdapter.Builder()
                .setEndpoint(Config.ENDPOINT)
                .setRequestInterceptor(requestInterceptor)
                .build();
        api = restAdapter.create(IRestAPI.class);
    }

    @Override
    public void requestSomething(final Callback callback) {
        api.getSomething(new Callback<Something>() {
            @Override
            public void success(Something something, Response response) {
                callback.success(something, response);
            }

            @Override
            public void failure(RetrofitError error) {
                if(error.getMessage().getId().euqals(ACCESS_TOKEN_EXPIRED))
                {
                    throw new AccessTokenExpired();
                }
                else if(error.getMessage().getId().euqals(USER_NOT_FOUND))
                {
                    throw new UsernamePasswordNotFound();
                }
                else // something else happened...
                {
                    throw error;
                }
            }
        });
    }

    @Override
    public void deleteSomething(final Callback callback) {
        api.deleteSomething(new Callback<Something>() {
            @Override
            public void success(Something something, Response response) {
                callback.success(something, response);
            }

            @Override
            public void failure(RetrofitError error) {
                if(error.getMessage().getId().euqals(SOMETHING_NOT_FOUND))
                {
                    ...
                    ...
                    Different exceptions
                }
                ...
            }
        });
    }

}

Naturally, I would only have to create my own callback interface using the success method.

Answer 1

RestAdapter, , , failure Callback<T> 4xx/5xx. :

public class Scratch {
    public static void main(String[] args) {
        Endpoints e = new RestAdapter.Builder()
                .setEndpoint("http://google.com")
                .setLogLevel(RestAdapter.LogLevel.FULL)
                .setErrorHandler(new ErrorHandler() {
                    @Override
                    public Throwable handleError(RetrofitError cause) {
                        switch (cause.getResponse().getStatus()) {
                            case 400:
                                /* Handle the expected body format */
                                cause.getBody();
                                throw new RuntimeException("Bad Request");
                            default:
                                /* Things and stuff */
                                throw new RuntimeException("");
                        }
                    }
                })
                .build()
                .create(Endpoints.class);

        e.getGoogle(new Callback<Response>() {
            @Override
            public void success(Response response, Response response2) {
                System.out.println("Got it");
            }

            @Override
            public void failure(RetrofitError error) {
                System.err.println("This won't ever be seen due to the error handler.");
            }
        });
    }

    private static interface Endpoints {
        @GET("/foo/bar")
        void getGoogle(Callback<Response> callback);
    }
}

edit: , , Callback . , . , , , , , .