import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.LinkedList;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.undo.UndoManager;

public class UndoDemo extends JFrame {

    private UndoManager undo = new UndoManager();
    private JTextArea textArea = new JTextArea();
 
    public UndoDemo() {

        super("Undo  Redo");
        LinkedList<String> cars = new LinkedList<String>();
        Container cp = getContentPane();
        cp.add(textArea = new JTextArea(10, 30), BorderLayout.CENTER);
        JPanel bp;
        cp.add(bp = new JPanel(), BorderLayout.SOUTH);

        undo = new UndoManager();
        textArea.getDocument().addUndoableEditListener(undo);
        
        JButton undoButton;
        bp.add(undoButton = new JButton("UNDO"));
       //cars.add(textArea);
        undoButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (undo.canUndo()) {
                    undo.undo();
                } else {
                    warn("Geri alinamaz");
                }
            }
        });

        JButton redoButton;
        bp.add(redoButton = new JButton("REDO"));
        redoButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (undo.canRedo()) {
                    undo.redo();
                } else {
                    warn("Ileri alinamaz");
                }
            }
        });
        pack();
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }

    void warn(String msg) {
        JOptionPane.showMessageDialog(this, "ERROR: " + msg, "ERROR",
                JOptionPane.WARNING_MESSAGE);
    }

    
    
    
    public static void main(String[] files) {
        
        /*
        cars.add();
        cars.add();
        cars.add();
        System.out.println(cars);
*/
        
        new UndoDemo().setVisible(true);
    }

}