Vaadin 7 - Navigating between views using UrlFragments

Nowadays when you want to navigate between Views you usually use the Navigator class. But I want to use UriFragments aswell. I have implemented following code so far but to be honest,I don't know how to use UriFragments correctly. Please help!

public class MyUI extends UI {

    Navigator navigator;

    protected  static final String MAINVIEW = "main";
    
    @Override
    protected void init(VaadinRequest vaadinRequest) {
        
        getPage().setTitle("Vaadin vulnerabilities");
        
        getPage().addUriFragmentChangedListener(new UriFragmentChangedListener() {
            
            @Override
            public void uriFragmentChanged(UriFragmentChangedEvent event) {
                enter(event.getUriFragment());
            }
        });
        
        enter(getPage().getUriFragment());
        
        navigator = new Navigator(this,this);
        navigator.addView(MAINVIEW, new MainView());
        navigator.addView("", new StartView());
    }
    
    void enter(String fragment) {
        
    }

    @WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
    @VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
    public static class MyUIServlet extends VaadinServlet {
    }
    
    public class StartView extends VerticalLayout implements View {
                  
        public StartView() {
                         
            //getPage().setUriFragment("StartView");
            
            Button button = new Button("Zur Hauptansicht",
                    new Button.ClickListener() {
                @Override
                public void buttonClick(ClickEvent event) {
                    
                    if(userNameTextField.getValue().equals("")|| userNameTextField.getValue().isEmpty()) {
                        Notification.show("Bitte einen gültigen Wert eingeben!");
                        return;
                    }
              
                    else {
                    
                        navigator.navigateTo(MAINVIEW + "/" + userNameTextField.getValue());
                        // What to do here with urlfragments?
                    }
                }
            }); 
            addComponent(button);
        }
   
        public void enter(ViewChangeEvent event) {
            
            
        }
    }

Hi,

the Navigator uses URI fragments anyway; I don't think there's any reason to create a Navigator if you want to implement your own URI fragments navigator.

-Olli