sclass TextChangingTableCellRenderer extends DefaultTableCellRenderer {
  O f; // func(S) -> S
  
  *(O *f) {}

  public Component getTableCellRendererComponent(JTable table, O value, boolean isSelected, boolean hasFocus, int row, int column) {
    Component c = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
    S s = strOrEmpty(value);
    setText(f == null ? s : str(callF(f, s)));
    ret c;
  }
}