Swing/CellEditorFocusCycle のバックアップ(No.3)

JTable table = makeTable();
ActionMap am = table.getActionMap();
Action sncc = am.get("selectNextColumnCell");
Action action = new AbstractAction() {
  @Override public void actionPerformed(ActionEvent e) {
    if (!table.isEditing() || !isEditorFocusCycle(table.getEditorComponent())) {
      // System.out.println("Exit editor");
      sncc.actionPerformed(e);
    }
  }
};
am.put("selectNextColumnCell2", action);

InputMap im = table.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_TAB, 0), "selectNextColumnCell2");
// ...
protected boolean isEditorFocusCycle(Component editor) {
  Component child = CheckBoxesEditor.getEditorFocusCycleAfter(editor);
  if (child != null) {
    child.requestFocus();
    return true;
  }
  return false;
}
// ...
public static Component getEditorFocusCycleAfter(Component editor) {
  Component fo = KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner();
  if (fo == null || !(editor instanceof Container)) {
    return null;
  }
  Container root = (Container) editor;
  if (!root.isFocusCycleRoot()) {
    root = root.getFocusCycleRootAncestor();
  }
  if (root == null) {
    return null;
  }
  // System.out.println("FocusCycleRoot: " + root.getClass().getName());
  FocusTraversalPolicy ftp = root.getFocusTraversalPolicy();
  Component child = ftp.getComponentAfter(root, fo);
  if (child != null && SwingUtilities.isDescendingFrom(child, editor)) {
    // System.out.println("requestFocus: " + child.getClass().getName());
    // child.requestFocus();
    return child;
  }
  return null;
}