1 /*
2 * This file is part of Domingo
3 * an Open Source Java-API to Lotus Notes/Domino
4 * hosted at http://domingo.sourceforge.net
5 *
6 * Copyright (c) 2003-2007 Beck et al. projects GmbH Munich, Germany (http://www.bea.de)
7 *
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 */
22
23 package de.bea.domingo.queue;
24
25 /***
26 * Interface definition of a general Queue.
27 *
28 * @author <a href="mailto:kriede@users.sourceforge.net">Kurt Riede</a>
29 */
30 public interface Queue {
31
32 /***
33 * Returns the number of objects in the queue.
34 *
35 * @return number of objects in the queue
36 */
37 int size();
38
39 /***
40 * Checks is the queue is empty or not.
41 *
42 * @return <code>true</code> if the queue is empty, else <code>false</code>
43 */
44 boolean isEmpty();
45
46 /***
47 * Enqueues an object to the queue.
48 *
49 * @param obj the object to enqueue
50 */
51 void enqueue(Object obj);
52
53 /***
54 * Dequeues an object from the queue.
55 *
56 * @return next object from the queue
57 * or <code>null</code> if the queue is empty
58 */
59 Object dequeue();
60 }