code: public Principal authenticate() throws AuthenticationException {
          try (AlpineQueryManager qm = new AlpineQueryManager()) {
              final ApiKey apiKey = qm.getApiKey(assertedApiKey);
              if (apiKey == null) {
                  throw new AuthenticationException();
              } else {
                  return apiKey;
              }
          }
      }
docs: Authenticates the API key (if it was specified in the X-Api-Key header)
  and returns a Principal if authentication is successful. Otherwise,
  returns an AuthenticationException.
  @return a Principal of which ApiKey is an instance of
  @throws AuthenticationException upon an authentication failure
  @since 1.0.0