public static AuthToken generateUserToken( String username )
    {
        if ( username == null || username.isEmpty() ) {
            throw new IllegalArgumentException( "Argument 'username' cannot be null." );
        }
        return new AuthToken( username );
    }
Constructs a new AuthToken that represents an authenticated user identified by
the provider username.

@param username the username to create an authToken token with.
@return the auth token for the user
xmppserver/src/main/java/org/jivesoftware/openfire/auth/AuthToken.java