code: public void getNewLines() {
          try {
              List<MonitorLine> lines;
              if (getAll()) {
                  lines = getSource().getLinesFrom(null);
              } else {
                  lines = getSource().getLinesFrom(actual);
              }
              updateLines(lines);
          } catch (Exception e) {
              notifyObservers(e);
          }
      }
docs: Looks for new lines