UndoListener.java

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class UndoListener implements ActionListener {

    private BoardManager bm;

    public UndoListener(BoardManager bm) {
        this.bm = bm;
    }

    /**
     * @param e
     *            ActionEvent
     *
     */
    public void actionPerformed(ActionEvent e) {
        bm.undo();
    }
}