1 /*
2 * File: EventQueue.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 import java.util.LinkedList;
25 import java.util.Queue;
26
27 import net.sf.webmancer.util.ContractChecker;
28
29 import org.apache.log4j.Logger;
30
31 /**
32 * @author Michal Burda
33 *
34 */
35 public class EventQueue implements IEventQueue {
36 /**
37 *
38 */
39 private static Logger logger = Logger.getLogger(EventQueue.class);
40
41 /**
42 *
43 */
44 private Queue<Event> events;
45
46 /**
47 * Constructs the EventQueue.
48 *
49 */
50 public EventQueue() {
51 this.events = new LinkedList<Event>();
52 }
53
54 /**
55 * @see net.sf.webmancer.base.IEventQueue#hasEvents()
56 */
57 public boolean hasEvents() {
58 return this.events.peek() != null;
59 }
60
61 /**
62 * @see net.sf.webmancer.base.IEventQueue#nextEvent()
63 */
64 public Event nextEvent() {
65 Event event = this.events.poll();
66 assert event != null;
67 if (logger.isDebugEnabled()) {
68 logger.debug("Dequeueing event " + event);
69 }
70 return event;
71 }
72
73 /**
74 * @see net.sf.webmancer.base.IEventQueue#putEvent(net.sf.webmancer.base.Event)
75 */
76 public void putEvent(final Event event) {
77 ContractChecker.mustNotBeNull(event, "event");
78
79 if (logger.isDebugEnabled()) {
80 logger.debug("Enqueueing event " + event);
81 }
82 this.events.offer(event);
83 }
84
85 }