The general usage pattern for a OpenID Provider is outlined below:

    // instantiate a ServerManager object
    public static ServerManager manager = new ServerManager();

    // configure the OpenID Provider's endpoint URL
    static
    {
        manager.setOPEndpointUrl("Http://my.openidprovider.com/server");
    }

    // 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());

        // caller will need to decide which of the following to use:
        // - GET HTTP-redirect to the return_to URL
        // - HTML FORM Redirection
        responseText = response.wwwFormEncoding();
    }
    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;