* {@inheritDoc}
*
* @throws IllegalStateException when AccessToken has already been retrieved or set
*/
public synchronized AccessToken getOAuthAccessToken(RequestToken requestToken) throws TwitterException {
OAuthSupport oauth = getOAuth();
AccessToken oauthAccessToken = oauth.getOAuthAccessToken(requestToken);
screenName = oauthAccessToken.getScreenName();
return oauthAccessToken;
}