Swing/CursorOfCellComponent のバックアップ(No.6)

class LinkCellList<E> extends JList<E> {
  private int prevIndex = -1;
  protected LinkCellList(ListModel<E> model) {
    super(model);
  }
  @Override public void updateUI() {
    setForeground(null);
    setBackground(null);
    setSelectionForeground(null);
    setSelectionBackground(null);
    super.updateUI();
    setFixedCellHeight(32);
    setCellRenderer(new LinkCellRenderer<>());
    //TEST: putClientProperty("List.isFileList", Boolean.TRUE);
  }
  @Override protected void processMouseMotionEvent(MouseEvent e) {
    Point pt = e.getPoint();
    int i = locationToIndex(pt);
    E s = getModel().getElementAt(i);
    Component c = getCellRenderer().getListCellRendererComponent(
        this, s, i, false, false);
    Rectangle r = getCellBounds(i, i);
    c.setBounds(r);
    if (prevIndex != i) {
      c.doLayout();
    }
    prevIndex = i;
    pt.translate(-r.x, -r.y);
    setCursor(
      Optional.ofNullable(SwingUtilities.getDeepestComponentAt(c, pt.x, pt.y))
        .map(Component::getCursor)
        .orElse(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR)));
  }
}