WatchListJob.java

/*
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.xwiki.watchlist.internal.job;

import java.util.Collection;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.quartz.Job;
import org.quartz.JobDataMap;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xwiki.watchlist.internal.DefaultWatchListNotifier;
import org.xwiki.watchlist.internal.WatchListEventMatcher;
import org.xwiki.watchlist.internal.api.WatchList;
import org.xwiki.watchlist.internal.api.WatchListEvent;
import org.xwiki.watchlist.internal.documents.WatchListJobClassDocumentInitializer;
import org.xwiki.watchlist.internal.notification.WatchListEventMimeMessageFactory;

import com.xpn.xwiki.XWikiException;
import com.xpn.xwiki.doc.XWikiDocument;
import com.xpn.xwiki.objects.BaseObject;
import com.xpn.xwiki.plugin.scheduler.AbstractJob;
import com.xpn.xwiki.web.Utils;

/**
 * WatchList abstract implementation of Quartz's Job.
 *
 * @version $Id: 2e1ba48a94e19157a871e1b9b114b80026cf5a54 $
 */
public class WatchListJob extends AbstractJob implements Job
{
    /**
     * Wiki page which contains the default watchlist email template.
     */
    public static final String DEFAULT_EMAIL_TEMPLATE = "XWiki.WatchListMessage";

    /**
     * Logger.
     */
    private static final Logger LOGGER = LoggerFactory.getLogger(WatchListJob.class);

    /**
     * Scheduler Job XObject.
     */
    private BaseObject schedulerJobObject;

    /**
     * Watchlist Job XObject.
     */
    private BaseObject watchListJobObject;

    /**
     * Caller component.
     */
    private WatchList watchlist;

    /**
     * Sets objects required by the Job : XWiki, XWikiContext, WatchListPlugin, etc.
     *
     * @param jobContext Context of the request
     * @throws Exception when the init of components fails
     */
    public void init(JobExecutionContext jobContext) throws Exception
    {
        JobDataMap data = jobContext.getJobDetail().getJobDataMap();

        this.watchlist = Utils.getComponent(WatchList.class);
        this.schedulerJobObject = (BaseObject) data.get("xjob");
        this.watchListJobObject =
            getXWikiContext().getWiki().getDocument(this.schedulerJobObject.getDocumentReference(), getXWikiContext())
                .getXObject(WatchListJobClassDocumentInitializer.DOCUMENT_REFERENCE);
    }

    /**
     * @return ID of the job
     */
    public String getId()
    {
        String className = this.getClass().getName();
        return className.substring(className.lastIndexOf(".") + 1);
    }

    /**
     * @return the previous job fire time
     */
    private Date getPreviousFireTime()
    {
        return this.watchListJobObject.getDateValue(WatchListJobClassDocumentInitializer.LAST_FIRE_TIME_FIELD);
    }

    /**
     * Save the date of the execution in the watchlist job object.
     *
     * @throws XWikiException if the job document can't be retrieved or if the save action fails
     */
    private void setPreviousFireTime() throws XWikiException
    {
        XWikiDocument doc =
            getXWikiContext().getWiki().getDocument(this.watchListJobObject.getDocumentReference(), getXWikiContext());

        this.watchListJobObject.setDateValue(WatchListJobClassDocumentInitializer.LAST_FIRE_TIME_FIELD, new Date());

        // Prevent version changes
        doc.setMetaDataDirty(false);
        doc.setContentDirty(false);

        getXWikiContext().getWiki().saveDocument(doc, "Updated last fire time", true, getXWikiContext());
    }

    /**
     * Retrieves all the XWiki.XWikiUsers who have requested to be notified by changes, i.e. who have an Object of class
     * WATCHLIST_CLASS attached AND who have chosen the current job for their notifications.
     *
     * @return a collection of document names pointing to the XWikiUsers wishing to get notified.
     */
    private Collection<String> getSubscribers()
    {
        return this.watchlist.getStore().getSubscribers(this.schedulerJobObject.getName());
    }

    /**
     * @return true if this job has subscribers, false otherwise
     */
    private boolean hasSubscribers()
    {
        Collection<String> subscribers = getSubscribers();

        return !subscribers.isEmpty();
    }

    /**
     * Method called from the scheduler.
     *
     * @param jobContext Context of the request
     * @throws JobExecutionException if the job execution fails.
     */
    @Override
    public void executeJob(JobExecutionContext jobContext) throws JobExecutionException
    {
        try {
            init(jobContext);

            if (this.watchListJobObject == null) {
                return;
            }

            Collection<String> subscribers = getSubscribers();

            // Stop here if nobody is interested.
            if (!hasSubscribers()) {
                return;
            }

            // Determine what happened since the last execution for everybody.
            Date previousFireTime = getPreviousFireTime();
            WatchListEventMatcher eventMatcher = Utils.getComponent(WatchListEventMatcher.class);
            List<WatchListEvent> events = eventMatcher.getEventsSince(previousFireTime);
            setPreviousFireTime();

            // Stop here if nothing happened in the meantime.
            if (events.size() == 0) {
                return;
            }

            // Notify all the interested subscribers of the events that occurred.
            // When processing the events, a subscriber will only be notified of events that interest him.
            Map<String, Object> notificationData = new HashMap<>();
            notificationData.put(DefaultWatchListNotifier.PREVIOUS_FIRE_TIME_VARIABLE, previousFireTime);

            String mailTemplate =
                this.watchListJobObject.getStringValue(WatchListJobClassDocumentInitializer.TEMPLATE_FIELD);
            notificationData.put(WatchListEventMimeMessageFactory.TEMPLATE_PARAMETER, mailTemplate);

            // Send the notification for processing.
            this.watchlist.getNotifier().sendNotification(subscribers, events, notificationData);
        } catch (Exception e) {
            // We're in a job, we don't throw exceptions
            LOGGER.error("Exception while running job", e);
        }
    }
}