SeamFramework.orgCommunity Documentation

Chapter 2. JSF web application example

Let's illustrate these ideas with a full example. We're going to implement user login/logout for an application that uses JSF. First, we'll define a Web Bean to hold the username and password entered during login:

@Named @RequestScoped

public class Credentials {
    private String username;
    private String password;
    public String getUsername() { return username; }
    public void setUsername(String username) { this.username = username; }
    public String getPassword() { return password; }
    public void setPassword(String password) { this.password = password; }

This Web Bean is bound to the login prompt in the following JSF form:


    <h:panelGrid columns="2" rendered="#{!login.loggedIn}">
        <h:outputLabel for="username">Username:</h:outputLabel>
        <h:inputText id="username" value="#{credentials.username}"/>
        <h:outputLabel for="password">Password:</h:outputLabel>
        <h:inputText id="password" value="#{credentials.password}"/>
    <h:commandButton value="Login" action="#{login.login}" rendered="#{!login.loggedIn}"/>
    <h:commandButton value="Logout" acion="#{login.logout}" rendered="#{login.loggedIn}"/>

The actual work is done by a session scoped Web Bean that maintains information about the currently logged-in user and exposes the User entity to other Web Beans:

@SessionScoped @Named

public class Login {
    @Current Credentials credentials;
    @PersistenceContext EntityManager userDatabase;
    private User user;
    public void login() {
        List<User> results = userDatabase.createQuery(
           "select u from User u where u.username=:username and u.password=:password")
           .setParameter("username", credentials.getUsername())
           .setParameter("password", credentials.getPassword())
        if ( !results.isEmpty() ) {
           user = results.get(0);
    public void logout() {
        user = null;
    public boolean isLoggedIn() {
       return user!=null;
    @Produces @LoggedIn User getCurrentUser() {
        return user;

Of course, @LoggedIn is a binding annotation:


public @interface LoggedIn {}

Now, any other Web Bean can easily inject the current user:

public class DocumentEditor {

    @Current Document document;
    @LoggedIn User currentUser;
    @PersistenceContext EntityManager docDatabase;
    public void save() {

Hopefully, this example gives a flavor of the Web Bean programming model. In the next chapter, we'll explore Web Beans dependency injection in greater depth.