public Authentication authenticate(Authentication authentication)
            throws AuthenticationException {
        final String username = (String) authentication.getPrincipal();
        final String password = (String) authentication.getCredentials();
        System.out.println(username + password);

        String searchFilter = "(&(objectClass=user)(sAMAccountName=" + username
                + "))";

        System.out.println(searchFilter);
        SearchControls searchControls = new SearchControls();
        searchControls.setSearchScope(SearchControls.SUBTREE_SCOPE);

        Hashtable<String, String> environment = new Hashtable<String, String>();
        environment.put(Context.INITIAL_CONTEXT_FACTORY,
                "com.sun.jndi.ldap.LdapCtxFactory");
        environment.put(Context.PROVIDER_URL, host);
        environment.put(Context.SECURITY_AUTHENTICATION, "simple");
        environment.put(Context.SECURITY_PRINCIPAL, username + "@" + domain);
        environment.put(Context.SECURITY_CREDENTIALS, password);

        System.out.println(environment);
        try {
            LdapContext ldapContext = new InitialLdapContext(environment, null);

            // Search objects in GC using filters
            NamingEnumeration<SearchResult> answer = ldapContext.search(
                    searchBase, searchFilter, searchControls);

            while (answer.hasMoreElements()) {
                SearchResult result = (SearchResult) answer.next();
                Attributes resultAttributes = result.getAttributes();
                Map<String, Object> response = null;
                System.out.println(resultAttributes);
                if (resultAttributes != null) {
                    response = new HashMap<String, Object>();
                    NamingEnumeration ne = resultAttributes.getAll();

                    while (ne.hasMore()) {
                        Attribute resultAttribute = (Attribute) ne.next();
                        response.put(resultAttribute.getID(),
                                resultAttribute.get());
                    }

                    ne.close();
                }

                User user = userService.getUser(username, true);

                return new LdapAuthentication(user, true);
            }
        } catch (Exception ex) {
            System.out.println(ex);
        }

        LdapAuthentication ldapAuthentication = new LdapAuthentication();
        ldapAuthentication.setName(username);
        ldapAuthentication.setPrincipal(username);
        ldapAuthentication.setCredentials(password);
        ldapAuthentication.setAuthenticated(false);

        return ldapAuthentication;
    }

    public boolean supports(Class<? extends Object> authentication) {
        return LdapAuthentication.class.isAssignableFrom(authentication
                .getClass());
    }