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1   /*
2    * File:    IEventQueue.java
3    * Created: 23.02.2006 7:33:19 
4    *
5    * Copyright 2007 Michal Burda.
6    *
7    * This program is free software; you can redistribute it and/or modify
8    * it under the terms of the GNU General Public License as published by
9    * the Free Software Foundation; either version 2 of the License, or
10   * (at your option) any later version.
11   *
12   * This program is distributed in the hope that it will be useful,
13   * but WITHOUT ANY WARRANTY; without even the implied warranty of
14   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15   * GNU General Public License for more details.
16   *
17   * You should have received a copy of the GNU General Public License
18   * along with this program; if not, write to the Free Software
19   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
20   */
21  
22  package net.sf.webmancer.base;
23  
24  
25  /**
26   * This interface represents a queue of events that wait for handling by a tree of widgets.
27   * 
28   * @author Michal Burda
29   */
30  public interface IEventQueue {
31      /**
32       * Put the event into the event queue.
33       * 
34       * @param event The event to put into this queue (must not be <code>null</code>)
35       */
36      void putEvent(Event event);
37      
38      /**
39       * Determine whether there are some events in the queue.
40       * 
41       * @return <code>true</code> if there are some events in the queue.
42       */
43      boolean hasEvents();
44      
45      /**
46       * Return the next event in the queue or <code>null</code> if the queue is empty.
47       * 
48       * @return the next event stored in the queue or <code>null</code> if the queue is empty.
49       */
50      Event nextEvent();
51  }