usernames and checking from servlet

[cambazz]

Hello,

I made usernames with urlrewrite filter like: www.mysite.com/username

so there are other pages like www.mysite.com/howto

I have to make sure that no user gets this username howto, if it is
referenced in urlrewrite.

how can i ask from a servlet, whether this name is referenced in
urlrewrite as a page name or not?

Best Regards,
C.B.