/*
* Copyright (c) 2009, 2010, 2011, 2012, B3log Team
*
* 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.
*/
package org.b3log.latke.cron;
import java.io.File;
import java.util.ArrayList;
import java.util.List;
import java.util.Timer;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.b3log.latke.Latkes;
import org.b3log.latke.RuntimeEnv;
import org.b3log.latke.servlet.AbstractServletListener;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
/**
* Cron jobs service.
*
* <p>
* Loads cron jobs configurations from cron.xml and schedules tasks.
* </p>
*
* @author <a href="mailto:DL88250@gmail.com">Liang Ding</a>
* @version 1.0.0.1, May 2, 2012
*/
public final class CronService {
/**
* Logger.
*/
private static final Logger LOGGER = Logger.getLogger(CronService.class.getName());
/**
* Cron jobs.
*/
private static final List<Cron> CRONS = new ArrayList<Cron>();
/**
* Constructs cron jobs and schedules them.
*/
public static void start() {
LOGGER.info("Constructing Cron Service....");
CRONS.clear();
final RuntimeEnv runtimeEnv = Latkes.getRuntimeEnv();
try {
switch (runtimeEnv) {
case LOCAL:
loadCronXML();
for (final Cron cron : CRONS) {
cron.setURL(Latkes.getServer() + Latkes.getContextPath() + cron.getUrl());
final Timer timer = new Timer();
timer.scheduleAtFixedRate(cron, Cron.SIXTY * Cron.THOUSAND, cron.getPeriod());
LOGGER.log(Level.FINER, "Scheduled a cron job[url={0}]", cron.getUrl());
}
LOGGER.log(Level.FINER, "[{0}] cron jobs", CRONS.size());
break;
case GAE:
break;
default:
throw new RuntimeException("Latke runs in the hell.... Please set the enviornment correctly");
}
} catch (final Exception e) {
throw new RuntimeException("Can not initialize Cron Service!", e);
}
LOGGER.info("Constructed Cron Service");
}
/**
* Loads cron.xml.
*/
private static void loadCronXML() {
final String webRoot = AbstractServletListener.getWebRoot();
final File cronXML = new File(webRoot + File.separator + "WEB-INF" + File.separator + "cron.xml");
if (!cronXML.exists()) {
LOGGER.log(Level.INFO, "Not found cron.xml, no cron jobs need to schedule");
return;
}
final DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
try {
final DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
final Document document = documentBuilder.parse(cronXML);
final Element root = document.getDocumentElement();
root.normalize();
final NodeList crons = root.getElementsByTagName("cron");
LOGGER.log(Level.CONFIG, "Reading cron jobs: ");
for (int i = 0; i < crons.getLength(); i++) {
final Element cronElement = (Element) crons.item(i);
final Element urlElement = (Element) cronElement.getElementsByTagName("url").item(0);
final Element descriptionElement = (Element) cronElement.getElementsByTagName("description").item(0);
final Element scheduleElement = (Element) cronElement.getElementsByTagName("schedule").item(0);
final String url = urlElement.getTextContent();
final String description = descriptionElement.getTextContent();
final String schedule = scheduleElement.getTextContent();
LOGGER.log(Level.CONFIG, "Cron[url={0}, description={1}, schedule={2}]", new Object[]{url, description, schedule});
CRONS.add(new Cron(url, description, schedule));
}
} catch (final Exception e) {
LOGGER.log(Level.SEVERE, "Reads cron.xml failed", e);
throw new RuntimeException(e);
}
}
/**
* Private default constructor.
*/
private CronService() {
}
}