Cerrar un JFrame desde dentro de un JPanel

Ventana.java

package com.jaureguialzo;

import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Ventana {
    private JButton cerrarButton;
    private JPanel panel;

    public Ventana() {
        cerrarButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                JFrame topFrame = (JFrame) SwingUtilities.getWindowAncestor(panel);
                topFrame.dispose();
            }
        });
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Ventana");
        frame.setContentPane(new Ventana().panel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }
}