1 /*
2 * Copyright 2005-2010 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.springframework.ws.transport.mail.monitor;
18
19 import javax.mail.Folder;
20 import javax.mail.Message;
21 import javax.mail.MessagingException;
22 import javax.mail.event.MessageCountAdapter;
23 import javax.mail.event.MessageCountEvent;
24 import javax.mail.event.MessageCountListener;
25
26 import org.springframework.util.Assert;
27
28 import com.sun.mail.imap.IMAPFolder;
29
30 /**
31 * Implementation of the {@link MonitoringStrategy} interface that uses the IMAP IDLE command for asynchronous message
32 * detection.
33 * <p/>
34 * <b>Note</b> that this implementation is only suitable for use with IMAP servers which support the IDLE command.
35 * Additionally, this strategy requires JavaMail version 1.4.1.
36 *
37 * @author Arjen Poutsma
38 * @since 1.5.0
39 */
40 public class ImapIdleMonitoringStrategy extends AbstractMonitoringStrategy {
41
42 private MessageCountListener messageCountListener;
43
44 @Override
45 protected void waitForNewMessages(Folder folder) throws MessagingException, InterruptedException {
46 Assert.isInstanceOf(IMAPFolder.class, folder);
47 IMAPFolder imapFolder = (IMAPFolder) folder;
48 // retrieve unseen messages before we enter the blocking idle call
49 if (searchForNewMessages(folder).length > 0) {
50 return;
51 }
52 if (messageCountListener == null) {
53 createMessageCountListener();
54 }
55 folder.addMessageCountListener(messageCountListener);
56 try {
57 imapFolder.idle();
58 }
59 finally {
60 folder.removeMessageCountListener(messageCountListener);
61 }
62 }
63
64 private void createMessageCountListener() {
65 messageCountListener = new MessageCountAdapter() {
66 @Override
67 public void messagesAdded(MessageCountEvent e) {
68 Message[] messages = e.getMessages();
69 for (Message message : messages) {
70 try {
71 // this will return the flow to the idle call, above
72 message.getLineCount();
73 }
74 catch (MessagingException ex) {
75 // ignore
76 }
77 }
78 }
79 };
80 }
81 }