Authenticating Users - Beginning Java Google App Engine - page 130

however, the method has no return type and the last parameter is an AsyncCallback
object.

Listing 6-4. The code for LoginServiceAsync.class

package com.appirio.timeentry.client;

import com.google.gwt.user.client.rpc.AsyncCallback;

public interface LoginServiceAsync {

public void login(String requestUri, AsyncCallback<LoginInfo> async);

}

Google Accounts Login Implementation
Now you need to create your server-side implementation (Listing 6-5) that uses
Google Accounts to actually authenticate your users and return their information if
successful.

Listing 6-5. The code for LoginServiceImpl.class

package com.appirio.timeentry.server;

import com.google.appengine.api.users.User;
import com.google.appengine.api.users.UserService;
import com.google.appengine.api.users.UserServiceFactory;
import com.appirio.timeentry.client.LoginInfo;
import com.appirio.timeentry.client.LoginService;
import com.google.gwt.user.server.rpc.RemoteServiceServlet;

public class LoginServiceImpl extends RemoteServiceServlet implements

LoginService {

public LoginInfo login(String requestUri) {

LoginInfo loginInfo = new LoginInfo();

UserService userService = UserServiceFactory.getUserService();

User user = userService.getCurrentUser();

if (user != null) {

loginInfo.setLoggedIn(true);

loginInfo.setLogoutUrl(userService.createLogoutURL(requestUri));