MailUtils.java

package org.jtheque.core.utils;

/*
 * Copyright JTheque (Baptiste Wicht)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import org.jtheque.utils.bean.Email;

import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.FileDataSource;
import javax.mail.BodyPart;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

import java.io.File;
import java.util.Date;
import java.util.Properties;

/**
 * Utility class for send mail. This class use Javamail to send email. 
 *
 * @author Baptiste Wicht
 */
public final class MailUtils {
    /**
     * Construct a new MailUtils. This class isn't instanciable.
     */
    private MailUtils() {
        throw new AssertionError();
    }

    /**
     * Send an email.
     *
     * @param email The email to send.
     * @param host  The host to send the message.
     *
     * @throws MessagingException Can throw this exception if an exception occurs during the send of the mail
     */
    public static void send(Email email, String host) throws MessagingException {
        MimeMessage msg = createMessage(host);

        configureMessage(email, msg);

        Multipart mp = new MimeMultipart();

        MimeBodyPart mbp1 = new MimeBodyPart();
        mbp1.setText(email.getMessage());

        mp.addBodyPart(mbp1);

        if (!email.getAttachedFiles().isEmpty()) {
            attachFiles(email, mp);
        }

        msg.setContent(mp);

        Transport.send(msg);
    }

    /**
     * Configure the email.
     *
     * @param email The email to get the infos from.
     * @param msg   The msg to configure.
     *
     * @throws MessagingException Throw if an error occurs during the treatment.
     */
    private static void configureMessage(Email email, MimeMessage msg) throws MessagingException {
        msg.setFrom(new InternetAddress(email.getFrom()));

        for (String to : email.getTo()) {
            msg.addRecipient(Message.RecipientType.TO, new InternetAddress(to));
        }

        msg.setSubject(email.getSubject());
        msg.setSentDate(new Date());
    }

    /**
     * Create a message with a specific host.
     *
     * @param host The host to use.
     *
     * @return The mime message.
     */
    private static MimeMessage createMessage(String host) {
        Properties props = new Properties();
        props.setProperty("mail.smtp.host", host);

        Session session = Session.getInstance(props, null);
        session.setDebug(false);

        return new MimeMessage(session);
    }

    /**
     * Attach files to the message.
     *
     * @param email The email to get the files from.
     * @param mp    The multi part message.
     *
     * @throws MessagingException Throw if an error occurs during the attaching files process.
     */
    private static void attachFiles(Email email, Multipart mp) throws MessagingException {
        for (File f : email.getAttachedFiles()) {
            BodyPart messageBodyPart = new MimeBodyPart();

            DataSource source = new FileDataSource(f);
            messageBodyPart.setDataHandler(new DataHandler(source));
            messageBodyPart.setFileName(source.getName());

            mp.addBodyPart(messageBodyPart);
        }
    }
}