AlertEmailer.java

package edu.umd.rhsmith.diads.meater.util;

import java.util.Properties;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

/**
 * A class that takes email information and can
 * thereafter send email message alerts.
 * 
 * @author dmonner
 */
public class AlertEmailer {

	/**
	 * The hostname of the SMTP server to use to send messages.
	 */
	private final String smtp;
	/**
	 * The email address to which alert message emails should be sent.
	 */
	private final String toEmail;
	/**
	 * The email address from which alert message emails will originate.
	 */
	private final String fromEmail;

	public AlertEmailer(final String smtp, final String toEmail,
			final String fromEmail) {
		this.smtp = smtp;
		this.toEmail = toEmail;
		this.fromEmail = fromEmail;
	}

	/**
	 * Sends an alert message, with the specified subject and message contents,
	 * using the SMTP server, to address, and from address that were read when
	 * this object was created.
	 * 
	 * @param subj
	 *            The subject line
	 * @param msg
	 *            The message body
	 * @throws MessagingException
	 *             If the email fails to send
	 */
	public void send(final String subj, final String msg)
			throws MessagingException {
		send(smtp, fromEmail, toEmail, subj, msg);
	}

	/**
	 * Sends an email using the given parameters.
	 * 
	 * @param smtp
	 *            The SMTP server to send from
	 * @param from
	 *            The from-address
	 * @param to
	 *            The to-address
	 * @param subj
	 *            The subject line
	 * @param body
	 *            The message body
	 * @throws MessagingException
	 *             If the email fails to send
	 */
	public static void send(final String smtp, final String from,
			final String to, final String subj, final String body)
			throws MessagingException {
		// Silently quit if we are missing any required email information
		if (smtp == null || from == null || to == null || smtp.isEmpty()
				|| from.isEmpty() || to.isEmpty())
			return;

		// Set the host smtp address
		final Properties mailProps = new Properties();
		mailProps.put("mail.smtp.host", smtp);

		// create some properties and get the default Session
		final Session session = Session.getDefaultInstance(mailProps, null);

		// create a message
		final Message msg = new MimeMessage(session);

		// set the from and to address
		final InternetAddress addressFrom = new InternetAddress(from);
		msg.setFrom(addressFrom);
		final InternetAddress addressTo = new InternetAddress(to);
		msg.setRecipient(Message.RecipientType.TO, addressTo);

		// set the subject and body
		msg.setSubject(subj);
		msg.setContent(body, "text/plain");

		// send the email message
		Transport.send(msg);
	}
}