import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.ButtonGroup;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;

public class Layout4 implements ActionListener {
    JPanel cards; //a panel that uses CardLayout
    final static String[] strings = 
        {"Component 1", 
         "Component 2 is so long-winded it makes the container wide", 
         "Component 3"};

    private static JComponent createComponent(String s) {
        JLabel l = new JLabel(s);
        l.setBorder(BorderFactory.createMatteBorder(5,5,5,5,
                                                    Color.DARK_GRAY));
        l.setHorizontalAlignment(JLabel.CENTER);
        return l;
    }

    public void addCardsToPane(Container pane) {
        JRadioButton[] rb = new JRadioButton[strings.length];
        ButtonGroup group = new ButtonGroup();
        JPanel buttons = new JPanel();
        buttons.setLayout(new BoxLayout(buttons,
                                        BoxLayout.PAGE_AXIS));
        
        for (int i= 0; i < strings.length; i++) {
            rb[i] = new JRadioButton("Show component #" + (i+1));
            rb[i].setActionCommand(String.valueOf(i));
            rb[i].addActionListener(this);
            group.add(rb[i]);
            buttons.add(rb[i]);
        }
        rb[0].setSelected(true);
        
        //Create the panel that contains the "cards".
        cards = new JPanel(new CardLayout());
        for (int i = 0; i < strings.length; i++) {
            cards.add(createComponent(strings[i]), String.valueOf(i));
        }

        pane.add(buttons, BorderLayout.NORTH);
        pane.add(cards, BorderLayout.CENTER);
    }

    public void actionPerformed(ActionEvent evt) {
        CardLayout cl = (CardLayout)(cards.getLayout());
        cl.show(cards, (String)evt.getActionCommand());
    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);

        //Create and set up the window.
        JFrame frame = new JFrame("Layout4");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        Layout4 demo = new Layout4();
        demo.addCardsToPane(frame.getContentPane());

        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}