csns.util.MassMailSender.java Source code

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Here is the source code for csns.util.MassMailSender.java

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/*
 * This file is part of the CSNetwork Services (CSNS) project.
 * 
 * Copyright 2012, Chengyu Sun (csun@calstatela.edu).
 * 
 * CSNS is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Affero General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option)
 * any later version.
 * 
 * CSNS is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for
 * more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with CSNS. If not, see http://www.gnu.org/licenses/agpl.html.
 */
package csns.util;

import java.util.ArrayList;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.mail.MailException;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;

import csns.model.core.AbstractMessage;
import csns.model.core.Subscribable;

/**
 * Sometimes an email server may reject an email as spam if the list of
 * recipients is too long. MassMailSender breaks the list of recipients into
 * groups (of 30 by default) and send a separate email to each group. It also
 * uses bcc so a recipient won't see other people's email addresses.
 */
@Component
public class MassMailSender {

    @Autowired
    JavaMailSender mailSender;

    @Autowired
    EmailUtils emailUtils;

    int maxRecipientsPerMessage = 30;

    private final static Logger logger = LoggerFactory.getLogger(MassMailSender.class);

    public MassMailSender() {
    }

    public void send(SimpleMailMessage email, List<String> addresses) {
        List<String> bccAddresses = new ArrayList<String>();
        for (int i = 0; i < addresses.size(); ++i) {
            if (!addresses.get(i).endsWith("@localhost"))
                bccAddresses.add(addresses.get(i));
            if (bccAddresses.size() >= maxRecipientsPerMessage
                    || bccAddresses.size() > 0 && i == addresses.size() - 1) {
                email.setBcc(bccAddresses.toArray(new String[0]));
                try {
                    mailSender.send(email);
                } catch (MailException e) {
                    logger.warn(e.getMessage());
                }
                logger.debug("sent email to " + StringUtils.collectionToCommaDelimitedString(bccAddresses));
                bccAddresses.clear();
            }
        }
    }

    public void send(AbstractMessage message, Subscribable subscribable) {
        SimpleMailMessage email = new SimpleMailMessage();
        email.setSubject(message.getSubject());
        email.setText(emailUtils.getText(message));
        email.setFrom(message.getAuthor().getPrimaryEmail());
        email.setTo(emailUtils.getAppEmail());
        send(email, emailUtils.getAddresses(subscribable));
    }

}