[xwiki-devs] shibboleth auth

Hi, I am using for my diploma thesis xwiki and i want to authorize users against shibboleth( http://shibboleth.internet2.edu/ ) I know that I must implements XWikiAuthService, but i don't know what the methods do. So, there are three methods public XWikiUser checkAuth(XWikiContext context) throws XWikiException; public void showLogin(XWikiContext context) throws XWikiException; public Principal authenticate(String username, String password, XWikiContext context) throws XWikiException; and which one is called when user come to xwiki? What is the difference between checkAuth and authenticate method? I want to implement lazy sessions, that means, when user click on login, he will be redirected to shibboleth auth provider. The same case is when user want to logout. Now i must to find out, if i need create user logins in database or if it possible to create some session only login. Thanks for reply Jan Kodera