code: @Override
      public String getActor() {
          String actor = (String) RequestContextHolder.currentRequestAttributes()
                  .getAttribute(actorSessionAttribute, RequestAttributes.SCOPE_SESSION);
          if (actor != null) {
              return actor;
          }
          return undefienedActorName;
      }
docs: {@inheritDoc}
  
  @see org.audit4j.core.MetaData#getActor()