OAuthUtils.getOAuthMessage(mc, request, REQUIRED_PARAMETERS);
new DefaultOAuthValidator().checkSingleParameter(oAuthMessage);
RequestToken token = dataProvider.getRequestToken(oAuthMessage.getToken());
if (token == null) {
throw new OAuthProblemException(OAuth.Problems.TOKEN_REJECTED);
}
OAuthAuthorizationData secData = new OAuthAuthorizationData();
if (!compareRequestSessionTokens(request, oAuthMessage)) {
addAuthenticityTokenToSession(secData, request);