/*  Copyright (C) 2003-2011 JabRef contributors.
    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.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package net.sf.jabref.undo;

import javax.swing.undo.CannotUndoException;
import javax.swing.undo.UndoManager;
import javax.swing.undo.UndoableEdit;
import javax.swing.event.UndoableEditEvent;

import net.sf.jabref.BasePanel;

public class CountingUndoManager extends UndoManager {

    private int unchangedPoint = 0,
	current = 0;
    private BasePanel panel = null;

    public CountingUndoManager(BasePanel basePanel) {
    	super();
	    panel = basePanel;
    }


    public synchronized boolean addEdit(UndoableEdit edit) {
	    current++;
        return super.addEdit(edit);
    }
    
    public synchronized void undo() throws CannotUndoException {
	    super.undo();
	    current--;
        panel.updateEntryEditorIfShowing();
    }

    public synchronized void redo() throws CannotUndoException {
	    super.redo();
	    current++;
        panel.updateEntryEditorIfShowing();
    }

    public synchronized void markUnchanged() {
    	unchangedPoint = current;
    }

    public boolean hasChanged() {
    	return !(current == unchangedPoint);
    }
}