private void scroll(boolean reversed) {
      int delta = myScrollBar.getBlockIncrement(reversed ? -1 : 1);
      if (reversed) delta = -delta;

      int oldValue = myScrollBar.getValue();
      int newValue = oldValue + delta;

      if (delta > 0 && newValue < oldValue) {
        newValue = myScrollBar.getMaximum();
      }
      else if (delta < 0 && newValue > oldValue) {
        newValue = myScrollBar.getMinimum();
      }
      if (oldValue != newValue) {
        myScrollBar.setValue(newValue);
      }
    }
private void scroll(boolean reversed)