private Map<String, OAuth2AuthorizationRequest> getAuthorizationRequests(HttpServletRequest request) {
		HttpSession session = request.getSession(false);
		Map<String, OAuth2AuthorizationRequest> authorizationRequests = session == null ? null :
				(Map<String, OAuth2AuthorizationRequest>) session.getAttribute(this.sessionAttributeName);
		if (authorizationRequests == null) {
			return new HashMap<>();
		}
		return authorizationRequests;
	}