code: public boolean isSet(_Fields field) {
      if (field == null) {
        throw new java.lang.IllegalArgumentException();
      }
  
      switch (field) {
      case TIMESTAMP:
        return isSetTimestamp();
      case VALUE:
        return isSetValue();
      case HOST:
        return isSetHost();
      }
      throw new java.lang.IllegalStateException();
    }
docs: Returns true if field corresponding to fieldID is set (has been assigned a value) and false otherwise