code: protected Principal getAccessTokenAuthenticationPrincipal(final AccessToken accessToken, final J2EContext context, final RegisteredService registeredService) {
          val currentPrincipal = accessToken.getAuthentication().getPrincipal();
          LOGGER.debug("Preparing user profile response based on CAS principal [{}]", currentPrincipal);
  
          val principal = this.scopeToAttributesFilter.filter(accessToken.getService(), currentPrincipal, registeredService, context, accessToken);
          LOGGER.debug("Created CAS principal [{}] based on requested/authorized scopes", principal);
  
          return principal;
      }
docs: Gets access token authentication principal.
  
  @param accessToken       the access token
  @param context           the context
  @param registeredService the registered service
  @return the access token authentication principal