private Set extractScopes(Map<String, String> requestParameters, String clientId) {
Set scopes = OAuth2Utils.parseParameterList(requestParameters.get(OAuth2Utils.SCOPE));
ClientDetails clientDetails = clientDetailsService.loadClientByClientId(clientId);
	if ((scopes == null || scopes.isEmpty())) {
		// If no scopes are specified in the incoming data, use the default values registered with the client
		// (the spec allows us to choose between this option and rejecting the request completely, so we'll take the
		// least obnoxious choice as a default).
		scopes = clientDetails.getScope();
	}
	if (checkUserScopes) {
		scopes = checkUserScopes(scopes, clientDetails);
	}
	return scopes;
}