private static AuthorizationCode retrieveAuthenticationCode(
final URI requestURI, final State state) throws ParseException {
final AuthenticationResponse authenticationResponse =
AuthenticationResponseParser.parse(requestURI);
if (authenticationResponse instanceof AuthenticationErrorResponse) {
final ErrorObject error =
((AuthenticationErrorResponse) authenticationResponse).getErrorObject();
throw new GNUOpenBusinessApplicationException(error.getDescription());
}
if (((AuthenticationSuccessResponse) authenticationResponse).getState() == null
|| !((AuthenticationSuccessResponse) authenticationResponse)
.getState()
.getValue()
.equals(state.getValue())) {
throw new GNUOpenBusinessApplicationException(
"State verification failed, recieved stated is not correct");
}
return ((AuthenticationSuccessResponse) authenticationResponse).getAuthorizationCode();
}