RecentChangesServlet.java :  » Wiki-Engine » VeryQuickWiki » vqwiki » servlets » Java Open Source

package vqwiki.servlets;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collection;
import java.util.ResourceBundle;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;

import vqwiki.ChangeLog;
import vqwiki.Environment;
import vqwiki.WikiBase;

/**
 * @author garethc
 * Date: 7/03/2003
 */
public class RecentChangesServlet extends VQWikiServlet {

    Collection all = null;
    private Object lock = new Object();
    private long lastReloadTime = 0;
    private static final Logger logger = Logger.getLogger(RecentChangesServlet.class);

    /**
     *
     */
    protected void doGet(HttpServletRequest request,
                         HttpServletResponse response)
                         throws ServletException, IOException
    {
        if (mustReload()) {
            try {
                String virtualWiki = (String)request.getAttribute("virtual-wiki");
                reload(virtualWiki);
            } catch (Exception e) {
                error(request, response, e);
                return;
            }
        }
        ResourceBundle messages = ResourceBundle.getBundle("ApplicationResources",
                                                           request.getLocale());
        request.setAttribute("title", messages.getString("recentchanges.title"));
        request.setAttribute("changes", all);
        dispatch("/jsp/recentChanges.jsp", request, response);
    }

    /**
     *
     */
    private void reload(String virtualWiki) throws Exception {
        synchronized (lock) {
            logger.debug("Reloading recent changes");
            Calendar cal = Calendar.getInstance();
            ChangeLog cl = WikiBase.getInstance().getChangeLogInstance();
            int n = Environment.getInstance()
                .getIntSetting(Environment.PROPERTY_RECENT_CHANGES_DAYS);
            if (n == 0) {
                n = 5;
            }
            all = new ArrayList();
            for (int i = 0; i < n; i++) {
                Collection col = cl.getChanges(virtualWiki, cal.getTime());
                if (col != null)
                  all.addAll(col);
                cal.add(Calendar.DATE, -1);
            }
            lastReloadTime = System.currentTimeMillis();
        }
    }

    /**
     *
     */
    private long getDeltaMillisReload() {
        return Environment.getInstance()
            .getRecentChangesRefreshInterval() * 1000 * 60;
    }

    /**
     *
     */
    private boolean mustReload() {
        long delta = getDeltaMillisReload();
        logger.debug("delta = " + delta);
        return ((System.currentTimeMillis() - lastReloadTime) > delta);
    }
}