String userName=request.getParameter(WebConstants.USER_NAME_PARAM);
String password=request.getParameter(WebConstants.PASSWORD_PARAM);
String accessingURL=request.getParameter("accessingURL");
if(userName != null) {
// login action
Person person=securityHandler.login(getFilterConfig().getServletContext(), httpRequest, httpResponse, userName, password);
if(person != null) {
// login successful, return originally requested resource
// don't like showing login in url because can't bookmark so redirect to it
httpResponse.sendRedirect(httpRequest.getContextPath() + accessingURL);
} else {