Question

I am developing a GWT web application. I have a login page with one textbox for user name, one passwordtextbox for password, and one submit button.

Now I want my login page has this feature: when a user logs in again, in the textbox for user name, he can find all previous inputs.

For the moment, I don’t have a clue how to do this. What should I look for? what kind of technique does this feature need?

An example for this feature is the login of hotmail. It can remember your previous input emails. I don’t need my application to remember the password.

It would be nice if anybody can give me an example.

Thanks in advance!

Best regards

Answer 1

I think Cookies would do the trick. By the way, I have noticed for some reason SuggestBox does not support adding mouse or focus handlers so I have used the depreciated focusListener in my example. Proper way of doing this would be to use a FocusPanel to wrap the SuggestBox to catch the focus events.

public class LoginExample implements EntryPoint {

    static long forgetMeIn = 1000 * 60 * 60 * 24 * 365 * 30; //30 years
    MultiWordSuggestOracle oracle;
    SuggestBox suggestBox;
    Button loginButton;
    Button showCookieButton;

    public void onModuleLoad() {
        oracle = new MultiWordSuggestOracle();
        suggestBox = new SuggestBox(oracle);
        updateSuggestBox();
        suggestBox.addFocusListener(new FocusListener() {
            @Override
            public void onLostFocus(Widget sender) {
            }               
            @Override
            public void onFocus(Widget sender) {
                suggestBox.showSuggestionList();
            }
        });
        loginButton = new Button("Login");
        loginButton.addClickHandler(new ClickHandler() {
            @Override
            public void onClick(ClickEvent event) {
                String username = suggestBox.getValue();
                if (username!=null && !username.equals("") && !cookieContains(username)){
                    addToCookie(username);
                    suggestBox.setValue("");
                    updateSuggestBox();
                    Window.alert("Next time I will remember " + username);
                }
            }
        });
        showCookieButton = new Button("ShowCookie");
        showCookieButton.addClickHandler(new ClickHandler() {
            @Override
            public void onClick(ClickEvent event) {
                Window.alert(LoginExample.this.getUsernames().toString());
            }
        });
        RootPanel.get().add(suggestBox);
        RootPanel.get().add(loginButton);
        RootPanel.get().add(showCookieButton);
    }

    private boolean cookieContains(String s){
        boolean contains = false;
        String users = Cookies.getCookie("usernames");
        if (users!=null){
            for (String username : users.split(":")){
                if (username.equals(s))
                    contains= true;
            }
        }
        return contains;
    }
    private void addToCookie(String username){
        String users = Cookies.getCookie("usernames");
        if (users!=null)
            Cookies.setCookie("usernames", users+":"+username, new Date(new Date().getTime() + forgetMeIn));
        else
            Cookies.setCookie("usernames", username, new Date(new Date().getTime() + forgetMeIn));
    }
    private List<String> getUsernames(){
        ArrayList<String> usernames = new ArrayList<String>();
        String users = Cookies.getCookie("usernames");
        if (users!=null){
            for (String username : users.split(":")){
                usernames.add(username);
            }
        }
        return usernames;
    }

    private void updateSuggestBox(){
        oracle.clear();
        List<String> usernames = getUsernames();
        oracle.setDefaultSuggestionsFromText(usernames);
        for (String username : usernames){
            oracle.add(username);
        }
    }
}