/**
* Copyright 2010 Daniel Guermeur and Amy Unruh
*
* 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.
*
* See http://connectrapp.appspot.com/ for a demo, and links to more information
* about this app and the book that it accompanies.
*/
package com.metadot.book.connectr.server.servlets;
import static com.google.appengine.api.labs.taskqueue.TaskOptions.Builder.url;
import java.io.IOException;
import java.util.Date;
import java.util.List;
import java.util.logging.Logger;
import javax.jdo.PersistenceManager;
import javax.jdo.Query;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.google.appengine.api.labs.taskqueue.Queue;
import com.google.appengine.api.labs.taskqueue.QueueFactory;
import com.metadot.book.connectr.server.PMF;
import com.metadot.book.connectr.server.domain.UserAccount;
/**
* update all feeds of 'active' users, by spawning a task for each such user.
*/
@SuppressWarnings("serial")
public class FeedUpdateLoggedInServlet extends HttpServlet {
private static final int MINS = 20; // def'n of 'active' user, in minutes
private static Logger logger = Logger.getLogger(FeedUpdateLoggedInServlet.class.getName());
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws IOException {
doPost(req, resp);
resp.setContentType("text/plain");
resp.getWriter().println("Starting 'feed update logged in' job");
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws IOException {
PersistenceManager pm = PMF.getNonTxnPm();
try {
List<UserAccount> results = getActiveUsers(pm);
if (results == null) {
return;
}
for (UserAccount user : results) {
// For each active user, spawn tasks to update their feeds
// and push an update notification as necessary
Queue queue = QueueFactory.getQueue("userfeedupdates");
queue.add(url("/feedupdateuser").param("uid", user.getUniqueId()).param("notify", "true"));
logger.info("queueing feedupdateuser for " + user.getUniqueId());
}
}
catch (Exception e) {
// e.printStackTrace();
logger.warning(e.getMessage());
}
finally {
pm.close();
}
}
@SuppressWarnings("unchecked")
private List<UserAccount> getActiveUsers(PersistenceManager pm) {
Long ts = (new Date()).getTime();
Long prior1 = ts - (1000 * (MINS * 60));
// we are looking for users active since this date
Date prior = new Date(prior1);
Query q = null;
List<UserAccount> results = null;
try {
q = pm.newQuery(UserAccount.class, "lastActive >= :d1");
results = (List<UserAccount>) q.execute(prior);
if (results.iterator().hasNext()) {
return results;
}
else {
return null;
}
}
catch (Exception e) {
// e.printStackTrace();
logger.warning(e.getMessage());
}
finally {
q.closeAll();
}
return results;
}
} //end class