static <A extends Component> A jPreferWidth(int w, A c) {
  swing {
    Dimension size = c.getPreferredSize();
    c.setPreferredSize(new Dimension(/*max(w, size.width) ??? */w, size.height));
  }
  ret c;
}

static <A extends Component> A jPreferWidth(A c, int w) {
  ret jPreferWidth(w, c);
}