+ /**
+ * Checks whether users are registered
+ * <p>
+ * @return Whether users are registered
+ */
+ boolean hasUsers ();
+
+ /**
+ * Adds user instance to database by preparing a complete user instance and
+ * sending it to the EJB. The data set in the controller is being verified,
+ * e.g. if the user name or email address is not used yet.
+ */
+ void addUser ();
+