private void validateConfig() {
    Preconditions.checkArgument(
        !Strings.isNullOrEmpty(config.getServiceName()), "Config is missing service name");
    Preconditions.checkArgument(
        !Strings.isNullOrEmpty(config.getRequestTokenUrl()), "Config is missing request token url");
    Preconditions.checkArgument(
        !Strings.isNullOrEmpty(config.getAuthorizationUrl()),
        "Config is missing authorization url");
    Preconditions.checkArgument(
        !Strings.isNullOrEmpty(config.getAccessTokenUrl()), "Config is missing access token url");
  }
General implementation of an {@link AuthDataGenerator} for OAuth1.
libraries/auth/src/main/java/org/datatransferproject/auth/OAuth1DataGenerator.java