content: /*
   *    This program is free software; you can redistribute it and/or modify
   *    it under the terms of the GNU General Public License as published by
   *    the Free Software Foundation; either version 2 of the License, or
   *    (at your option) any later version.
   *
   *    This program is distributed in the hope that it will be useful,
   *    but WITHOUT ANY WARRANTY; without even the implied warranty of
   *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *    GNU General Public License for more details.
   *
   *    You should have received a copy of the GNU General Public License
   *    along with this program; if not, write to the Free Software
   *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  /*
   *    Copyable.java
   *    Copyright (C) 2005 University of Waikato, Hamilton, New Zealand
   *
   */
  
  package weka.core;
  
  /**
   * Interface implemented by classes that support undo.
   *
   * @author FracPete (fracpete at waikato dot ac dot nz)
   * @version $Revision: 5953 $
   */
  public interface Undoable {
    /**
     * returns whether undo support is enabled
     */
    public boolean isUndoEnabled();
    
    /**
     * sets whether undo support is enabled
     */
    public void setUndoEnabled(boolean enabled);
  
    /**
     * removes the undo history
     */
    public void clearUndo();
    
    /**
     * returns whether an undo is possible, i.e. whether there are any undo points
     * saved so far
     * 
     * @return returns TRUE if there is an undo possible 
     */
    public boolean canUndo();
    
    /**
     * undoes the last action
     */
    public void undo();
    
    /**
     * adds an undo point to the undo history 
     */
    public void addUndoPoint();
  }
  