JListのセルに配置したJLabelのテキストを編集する

class EditableList<E extends ListItem> extends JList<E> {
  private transient MouseInputAdapter handler;
  protected final Container glassPane = new EditorGlassPane();
  protected final JTextField editor = new JTextField();
  protected final Action startEditing = new AbstractAction() {
    @Override public void actionPerformed(ActionEvent e) {
      getRootPane().setGlassPane(glassPane);
      int idx = getSelectedIndex();
      ListItem item = getSelectedValue();
      Rectangle rect = getCellBounds(idx, idx);
      Point p = SwingUtilities.convertPoint(
          EditableList.this, rect.getLocation(), glassPane);
      rect.setLocation(p);
      int h = editor.getPreferredSize().height;
      rect.y = rect.y + rect.height - h - 1;
      rect.height = h;
      rect.grow(-2, 0);
      editor.setBounds(rect);
      editor.setText(item.title);
      editor.selectAll();
      glassPane.add(editor);
      glassPane.setVisible(true);
      editor.requestFocusInWindow();
    }
  };
  protected final Action cancelEditing = new AbstractAction() {
    @Override public void actionPerformed(ActionEvent e) {
      glassPane.setVisible(false);
    }
  };
  protected final Action renameTitle = new AbstractAction() {
    @Override public void actionPerformed(ActionEvent e) {
      String title = editor.getText().trim();
      int index = getSelectedIndex();
      if (!title.isEmpty() && index >= 0) {
        E item = getModel().getElementAt(index);
        item.setTitle(title);
      }
      glassPane.setVisible(false);
    }
  };

  protected EditableList(DefaultListModel<E> model) {
    super(model);
    editor.setBorder(BorderFactory.createLineBorder(Color.BLACK, 1));
    editor.setHorizontalAlignment(SwingConstants.CENTER);
    // editor.setOpaque(false);
    // editor.setLineWrap(true);

    InputMap im = editor.getInputMap(JComponent.WHEN_FOCUSED);
    im.put(KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0), "rename-title");
    im.put(KeyStroke.getKeyStroke(KeyEvent.VK_ESCAPE, 0), "cancel-editing");

    ActionMap am = editor.getActionMap();
    am.put("rename-title", renameTitle);
    am.put("cancel-editing", cancelEditing);

    addMouseListener(new MouseAdapter() {
      @Override public void mouseClicked(MouseEvent e) {
        int idx = getSelectedIndex();
        Rectangle rect = getCellBounds(idx, idx);
        if (rect == null) {
          return;
        }
        int h = editor.getPreferredSize().height;
        rect.y = rect.y + rect.height - h;
        rect.height = h;
        boolean isDoubleClick = e.getClickCount() >= 2;
        if (isDoubleClick && rect.contains(e.getPoint())) {
          startEditing.actionPerformed(new ActionEvent(
              e.getComponent(), ActionEvent.ACTION_PERFORMED, ""));
        }
      }
    });
    getInputMap(JComponent.WHEN_FOCUSED).put(
        KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0), "start-editing");
    getActionMap().put("start-editing", startEditing);
  }

  @Override public void updateUI() {
    removeMouseListener(handler);
    setSelectionForeground(null);
    setSelectionBackground(null);
    setCellRenderer(null);
    super.updateUI();
    setLayoutOrientation(JList.HORIZONTAL_WRAP);
    getSelectionModel().setSelectionMode(
        ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
    setVisibleRowCount(0);
    setFixedCellWidth(56);
    setFixedCellHeight(56);
    setBorder(BorderFactory.createEmptyBorder(5, 10, 5, 10));
    setCellRenderer(new ListItemListCellRenderer<>());
    handler = new ClearSelectionListener();
    addMouseListener(handler);
  }

  protected JTextComponent getEditorTextField() {
    return editor;
  }

  private class EditorGlassPane extends JComponent {
    protected EditorGlassPane() {
      super();
      setOpaque(false);
      setFocusTraversalPolicy(new DefaultFocusTraversalPolicy() {
        @Override public boolean accept(Component c) {
          return Objects.equals(c, getEditorTextField());
        }
      });
      addMouseListener(new MouseAdapter() {
        @Override public void mouseClicked(MouseEvent e) {
          if (!getEditorTextField().getBounds().contains(e.getPoint())) {
            renameTitle.actionPerformed(new ActionEvent(
                e.getComponent(), ActionEvent.ACTION_PERFORMED, ""));
          }
        }
      });
    }

    @Override public void setVisible(boolean flag) {
      super.setVisible(flag);
      setFocusTraversalPolicyProvider(flag);
      setFocusCycleRoot(flag);
    }
  }
}