src/main/java/org/efaps/ui/filter/AbstractAuthenticationFilter.java
@Override
    protected void doFilter(final HttpServletRequest _request,
                            final HttpServletResponse _response,
                            final FilterChain _chain)
        throws IOException, ServletException
    {
        if (isLoggedIn(_request)) {
            _chain.doFilter(_request, _response);
        } else {
            doAuthenticate(_request, _response, _chain);
        }
    }
@Override
    protected void doFilter(final HttpServletRequest _request,
                            final HttpServletResponse _response,
                            final FilterChain _chain)
        throws IOException, ServletException
    {
        if (isLoggedIn(_request)) {
            _chain.doFilter(_request, _response);
        } else {
            doAuthenticate(_request, _response, _chain);
        }
    }
If the current user is already logged in, nothing is filtered.
@param _request      HttpServletRequest
@param _response     HttpServletResponse
@param _chain        FilterChain
@see #doAuthenticate
@throws IOException on error
@throws ServletException on error