about confluence sso

[hanlinbo]

i have three application . SSO(CAS SSO) application sso.com, A application app.com,confluence application bpp.com,they deploy in different server.now A application login(login to SSO application) and save the cookie a  "Asession=***" ,and open new windows in browse or A redirection to confluence ,i override ConfluenceAuthenticator.(i want A redirection to B needn't login).

public class MySSOAuthenticator extends ConfluenceAuthenticator
{

    public static final String LOGIN_SOURCE = "MyCustomSSO";

    private static final Logger log = LoggerFactory.getLogger(ExampleSSOAuthenticator.class);

    public Principal getUser(HttpServletRequest request, HttpServletResponse response)
    {
       Cookie[] cookies = request.getCookies();
       Enumeration headers= request.getHeaderNames();
//** i can't get the Asession from cookies or headers(has Iteration the cookies or headers)
        String username =MySsoApi(asession)
        Principal existingUser = getUserFromSession(request);
        if (existingUser != null)
        {
            log.debug(String.format("User %s is already logged in.", existingUser.getName()));
            return existingUser;
        }