import java.util.Properties;
    
    import javax.mail.Folder;
    import javax.mail.Message;
    import javax.mail.Session;
    import javax.mail.Store;
    import javax.mail.URLName;
    
    import org.jboss.seam.mail.core.EmailMessage;
    import org.jboss.seam.mail.util.MessageConverter;
    
    import com.sun.mail.pop3.POP3SSLStore;
    
    public class Popper {
    
        public static void main(String[] args) throws Exception {
    
            String SSL_FACTORY = "javax.net.ssl.SSLSocketFactory";
    
            Properties pop3Props = new Properties();
    
             pop3Props.setProperty("mail.pop3.socketFactory.class", SSL_FACTORY);
             pop3Props.setProperty("mail.pop3.socketFactory.fallback", "false");
             pop3Props.setProperty("mail.pop3.port", "995");
             pop3Props.setProperty("mail.pop3.socketFactory.port", "995");
    
             URLName url = new URLName("pop3", "pop.example.com", 995, "", "foo@example.com", "mypass");
    
             Session session = Session.getInstance(pop3Props, null);
             Store store = new POP3SSLStore(session, url);
             store.connect();
    
             Folder inbox = store.getFolder("INBOX");
             inbox.open(Folder.READ_ONLY);
    
             Message[] messages = inbox.getMessages();
    
             if (messages.length == 0) {
                 System.out.println("No Messages Found");
             }
    
             List<EmailMessage> emailMessages = new ArrayList<EmailMessage>();
    
             for (Message m : messages) {
                 emailMessages.add(MessageConverter.convert(m));
             }
    
             inbox.close(false);
             store.close();
        }
    }

public class MailTransporterImpl implements MailTransporter {
    
        private Session session;
    
        public MailTransporterImpl(Session session) {
            this.session = session;
        }
    
        public EmailMessage send(EmailMessage emailMessage) {
            MailUtility.send(emailMessage, session);
            return emailMessage;
        }
    }

public class MailQueueTransporter implements Serializable, MailTransporter {
    
        private static final long serialVersionUID = 1L;
    
        @Inject
        @QueuedEmail
        private Event<MimeMessage> queueEvent;
    
        @Inject
        @ExtensionManaged
        private Instance<Session> session;
    
        @Override
        public EmailMessage send(EmailMessage emailMessage) {
    
            MimeMessage msg = MailUtility.createMimeMessage(emailMessage, session.get());
            queueEvent.fire(msg);
    
            return emailMessage;
        }
    }

@Qualifier
    @Target({ ElementType.TYPE, ElementType.METHOD, ElementType.PARAMETER, ElementType.FIELD })
    @Retention(RetentionPolicy.RUNTIME)
    public @interface QueuedEmail { }

public class MailQueueReceiver {
    
        @Inject
        private Logger log;
    
        public static final String mailQueueFolder = "/var/data/mailQueue/";
    
        public void receiveMessage(@Observes @QueuedEmail MimeMessage msg) {
            log.debugf("Writing queued message to disk");
            OutputStream os;
            try {
                os = Files.newOutputStreamSupplier(
                  new File(mailQueueFolder + UUID.randomUUID())).getOutput();
                msg.writeTo(os);
                os.close();
            } catch (IOException e) {
                throw new SendFailedException("Failed to Write Message to Queue", e);
            } catch (MessagingException e) {
                throw new SendFailedException(e);
            }
        }
    }

@Singleton
    public class MailQueueSender {
    
        @Inject
        private Logger log;
    
        @Inject
        @ExtensionManaged
        private Session session;
    
        private String mailQueueFolder;
    
        @PostConstruct
        public void postConstruct() {
            mailQueueFolder = MailQueueReceiver.mailQueueFolder;
            File queueFolder = new File(mailQueueFolder);
            session.getProperties().put("mail.smtp.connectiontimeout", 15000);
            session.getProperties().put("mail.smtp.timeout", 15000);
            log.infof("Initialized Mail Queue with %s messages in queue", queueFolder.listFiles().length);
        }
    
        @Schedule(second = "15,45", minute = "*", hour = "*", persistent = false)
        public void sendQueue() throws InterruptedException {
    
            File queueFolder = new File(mailQueueFolder);
            LinkedList<File> files = new LinkedList<File>(Arrays.asList(queueFolder.listFiles()));
    
            while (!files.isEmpty()) {
                File file = files.peek();
                InputStream is;
                try {
                    is = Files.newInputStreamSupplier(file).getInput();
                    RootMimeMessage msg = new RootMimeMessage(session, is);
                    msg.setMessageId(generateMessageId());
                    Transport.send(msg);
                    log.debug("Sent Mail Message: " + msg.getMessageID());
                    is.close();
                    files.pop();
                    file.delete();
                }
                catch (IOException e) {
                    throw new SendFailedException("Failed to read message from Disk: " + file.getName(), e);
                }
                catch (MessagingException e) {
                    throw new SendFailedException("Send Failed for Message: " + file.getName(), e);
                }
            }
        }
    
        private String generateMessageId() {
            String mailerDomainName = session.getProperty("mail.seam.domainName");
            if (mailerDomainName != null && mailerDomainName.length() > 0) {
                return UUID.randomUUID().toString() + "@" + mailerDomainName;
            }
            else {
                return UUID.randomUUID().toString() + "@" + MailUtility.getHostName();
            }
        }
    }