CardLayoutを使ってJTabbedPane風のコンポーネントを作成

class CardLayoutTabbedPane extends JPanel {
  protected final CardLayout cardLayout = new CardLayout();
  protected final JPanel tabPanel = new JPanel(new GridLayout(1, 0, 0, 0));
  protected final JPanel wrapPanel = new JPanel(new BorderLayout(0, 0));
  protected final JPanel contentsPanel = new JPanel(cardLayout);
  protected final ButtonGroup bg = new ButtonGroup();
  public CardLayoutTabbedPane() {
    super(new BorderLayout());
    int left  = 1;
    int right = 3;
    tabPanel.setBorder(
      BorderFactory.createEmptyBorder(1, left, 0, right));
    contentsPanel.setBorder(
      BorderFactory.createEmptyBorder(4, left, 2, right));
    wrapPanel.add(tabPanel);
    wrapPanel.add(new JLabel("test:"), BorderLayout.WEST);
    add(wrapPanel, BorderLayout.NORTH);
    add(contentsPanel);
  }

  public void addTab(String title, Component comp) {
    JRadioButton b = new TabButton(new AbstractAction(title) {
      @Override public void actionPerformed(ActionEvent e) {
        cardLayout.show(contentsPanel, title);
      }
    });
    tabPanel.add(b);
    bg.add(b);
    b.setSelected(true);
    contentsPanel.add(comp, title);
    cardLayout.show(contentsPanel, title);
  }
}