/* -*- Mode: java; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.0 (the "License"); you may not use this file except in
 * compliance with the License.  You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is the Grendel mail/news client.
 *
 * The Initial Developer of the Original Code is Netscape Communications
 * Corporation.  Portions created by Netscape are Copyright (C) 1997
 * Netscape Communications Corporation.  All Rights Reserved.
 *
 * Created: Terry Weissman <terry@netscape.com>, 17 Sep 1997.
 */

package grendel.view;

import java.util.Enumeration;

/** Anyone who wants to know when messages are added, removed, or tweaked in
 * a MessageSetView can implement this and add themselves to that
 * MessageSetView's list of observers.
 */

public interface MessageSetViewObserver {
  /** Some messages changed.  Each enumeration parameter might be null, or
    * it might be an enumeration of ViewedMessage objects.
    * @param inserted           new messages that have appeared
    * @param deleted            old messages that are no longer considered
    *                           part of the MessageSetView
    * @param changed            Messages that have had their internals tweaked
    *                           in some way
    */

  public void messagesChanged(Enumeration inserted,
                              Enumeration deleted,
                              Enumeration changed);
};