36.2.1 Architecture of the async-war Module

The async-war module consists of a single stateless session bean, MailerBean, and a JavaServer Faces web application front end that uses Facelets tags in XHTML files to display a form for users to enter the email address for the recipient of an email. The status of the email is updated when the email is finally sent.

The MailerBean session bean injects a JavaMail resource used to send an email message to an address specified by the user. The message is created, modified, and sent using the JavaMail API. The session bean looks like this:

@Named
@Stateless
public class MailerBean {
    @Resource(name="mail/myExampleSession")
    private Session session;
    private static final Logger logger = 
            Logger.getLogger(MailerBean.class.getName());

    @Asynchronous
    public Future<String> sendMessage(String email) {
        String status;
        try {
            Properties properties = new Properties();            properties.put("mail.smtp.port", "3025");            session = Session.getInstance(properties);                        Message message = new MimeMessage(session);
            message.setFrom();
            message.setRecipients(Message.RecipientType.TO,
                    InternetAddress.parse(email, false));
            message.setSubject("Test message from async example");
            message.setHeader("X-Mailer", "JavaMail");
            DateFormat dateFormatter = DateFormat
                    .getDateTimeInstance(DateFormat.LONG, DateFormat.SHORT);
            Date timeStamp = new Date();
            String messageBody = "This is a test message from the async "
                    + "example of the Java EE Tutorial. It was sent on "
                    + dateFormatter.format(timeStamp)
                    + ".";
            message.setText(messageBody);
            message.setSentDate(timeStamp);
            Transport.send(message);
            status = "Sent";
            logger.log(Level.INFO, "Mail sent to {0}", email);
        } catch (MessagingException ex) {
            logger.severe("Error in sending message.");
            status = "Encountered an error: " + ex.getMessage();
            logger.severe(ex.getMessage());
        }
        return new AsyncResult<>(status);
    }
}

The injected JavaMail resource can be configured through the GlassFish Server Administration Console, through a GlassFish Server administrative command, or through a resource configuration file packaged with the application. The resource configuration can be modified at runtime by the GlassFish Server administrator to use a different mail server or transport protocol.

The web client consists of a Facelets template, template.xhtml; two Facelets clients, index.xhtml and response.xhtml; and a JavaServer Faces managed bean, MailerManagedBean. The index.xhtml file contains a form for the target email address. When the user submits the form, the MailerManagedBean.send method is called. This method uses an injected instance of the MailerBean session bean to call MailerBean.sendMessage. The result is sent to the response.xhtml Facelets view.

36.2.2 Running the async Example

You can use either NetBeans IDE or Maven to build, package, deploy, and run the async example.