public class SampleServer
{
    // instantiate a ServerManager object
    public ServerManager manager = new ServerManager();

    public SampleServer()
    {
        manager.setOPEndpointUrl("Http://my.openidprovider.com/server");
    }

    public String processRequest(HttpServletRequest httpReq,
                                 HttpServletResponse httpResp)
            throws Exception
    {
        // extract the parameters from the request
        ParameterList request = new ParameterList(httpReq.getParameterMap());

        String mode = request.hasParameter("openid.mode") ?
                request.getParameterValue("openid.mode") : null;

        Message response;
        String responseText;

        if ("associate".equals(mode))
        {
            // --- process an association request ---
            response = manager.associationResponse(request);
            responseText = response.keyValueFormEncoding();
        }
        else if ("checkid_setup".equals(mode)
                || "checkid_immediate".equals(mode))
        {
            // interact with the user and obtain data needed to continue
            List userData = userInteraction(request);

            String userSelectedId = (String) userData.get(0);
            String userSelectedClaimedId = (String) userData.get(1);
            Boolean authenticatedAndApproved = (Boolean) userData.get(2);

            // --- process an authentication request ---
            response = manager.authResponse(request,
                    userSelectedId,
                    userSelectedClaimedId,
                    authenticatedAndApproved.booleanValue());

            if (response instanceof DirectError)
                return directResponse(httpResp, response.keyValueFormEncoding());
            else
            {
                // caller will need to decide which of the following to use:

                // option1: GET HTTP-redirect to the return_to URL
                return response.getDestinationUrl(true);

                // option2: HTML FORM Redirection
                //RequestDispatcher dispatcher =
                //        getServletContext().getRequestDispatcher("formredirection.jsp");
                //httpReq.setAttribute("prameterMap", response.getParameterMap());
                //httpReq.setAttribute("destinationUrl", response.getDestinationUrl(false));
                //dispatcher.forward(request, response);
                //return null;
            }
        }
        else if ("check_authentication".equals(mode))
        {
            // --- processing a verification request ---
            response = manager.verify(request);
            responseText = response.keyValueFormEncoding();
        }
        else
        {
            // --- error response ---
            response = DirectError.createDirectError("Unknown request");
            responseText = response.keyValueFormEncoding();
        }

        // return the result to the user
        return responseText;
    }

    private List userInteraction(ParameterList request) throws ServerException
    {
        throw new ServerException("User-interaction not implemented.");
    }

    private String directResponse(HttpServletResponse httpResp, String response)
            throws IOException
    {
        ServletOutputStream os = httpResp.getOutputStream();
        os.write(response.getBytes());
        os.close();

        return null;
    }
}