Java tutorial
/** * File ./src/main/java/de/lemo/dms/processing/questions/QCourseUserPaths.java * Lemo-Data-Management-Server for learning analytics. * Copyright (C) 2013 * Leonard Kappe, Andreas Pursian, Sebastian Schwarzrock, Boris Wenzlaff * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * any later version. * * This program 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. **/ /** * File ./main/java/de/lemo/dms/processing/questions/QCourseUserPaths.java * Date 2013-01-24 * Project Lemo Learning Analytics */ package de.lemo.dms.processing.questions; import java.util.ArrayList; import java.util.List; import java.util.Map; import java.util.Map.Entry; import java.util.Set; import java.util.concurrent.TimeUnit; import javax.ws.rs.FormParam; import javax.ws.rs.POST; import javax.ws.rs.Path; import org.codehaus.jettison.json.JSONArray; import org.codehaus.jettison.json.JSONException; import org.codehaus.jettison.json.JSONObject; import org.hibernate.Criteria; import org.hibernate.Session; import org.hibernate.criterion.Restrictions; import com.google.common.base.Stopwatch; import com.google.common.collect.BiMap; import com.google.common.collect.HashBiMap; import com.google.common.collect.Lists; import com.google.common.collect.Maps; import com.google.common.collect.Sets; import de.lemo.dms.core.config.ServerConfiguration; import de.lemo.dms.db.IDBHandler; import de.lemo.dms.db.mapping.CourseMining; import de.lemo.dms.db.mapping.abstractions.ILogMining; import de.lemo.dms.processing.MetaParam; import de.lemo.dms.processing.Question; import de.lemo.dms.processing.StudentHelper; import de.lemo.dms.processing.resulttype.UserPathLink; /** * Computes paths for users * * @author Leonard Kappe * @author Sebastian Schwarzrock */ @Path("courseuserpaths") public class QCourseUserPaths extends Question { @SuppressWarnings("unchecked") @POST public JSONObject compute(@FormParam(MetaParam.COURSE_IDS) final List<Long> courses, @FormParam(MetaParam.START_TIME) final Long startTime, @FormParam(MetaParam.END_TIME) Long endTime, @FormParam(MetaParam.GENDER) List<Long> gender) throws JSONException { validateTimestamps(startTime, endTime); final Stopwatch stopWatch = new Stopwatch(); stopWatch.start(); final IDBHandler dbHandler = ServerConfiguration.getInstance().getMiningDbHandler(); final Session session = dbHandler.getMiningSession(); Criteria criteria; List<Long> users = new ArrayList<Long>(StudentHelper.getCourseStudentsAliasKeys(courses, gender).values()); criteria = session.createCriteria(ILogMining.class, "log").add(Restrictions.in("log.course.id", courses)) .add(Restrictions.between("log.timestamp", startTime, endTime)) .add(Restrictions.eq("log.action", "view")); if (!users.isEmpty()) { criteria.add(Restrictions.in("log.user.id", users)); } else { this.logger.debug("No users found for courses. Returning empty JSONObject."); return new JSONObject(); } final List<ILogMining> logs = criteria.list(); this.logger.debug("Found " + users.size() + " actions. " + +stopWatch.elapsedTime(TimeUnit.SECONDS)); long courseCount = 0; final BiMap<CourseMining, Long> courseNodePositions = HashBiMap.create(); final Map<Long/* user id */, List<Long/* course id */>> userPaths = Maps.newHashMap(); this.logger.debug("Paths fetched: " + logs.size() + ". " + stopWatch.elapsedTime(TimeUnit.SECONDS)); Map<Long, Long> idToAlias = StudentHelper.getCourseStudentsRealKeys(courses, gender); for (final ILogMining log : logs) { final CourseMining course = log.getCourse(); Long nodeID = courseNodePositions.get(course); if (nodeID == null) { nodeID = courseCount++; courseNodePositions.put(course, nodeID); } final long userId = idToAlias.get(log.getUser().getId()); List<Long> nodeIDs = userPaths.get(userId); if (nodeIDs == null) { nodeIDs = Lists.newArrayList(); userPaths.put(userId, nodeIDs); } nodeIDs.add(nodeID); } this.logger.debug("userPaths: " + userPaths.size()); final Map<Long /* node id */, List<UserPathLink>> coursePaths = Maps.newHashMap(); for (final Entry<Long, List<Long>> userEntry : userPaths.entrySet()) { UserPathLink lastLink = null; for (final Long nodeID : userEntry.getValue()) { List<UserPathLink> links = coursePaths.get(nodeID); if (links == null) { links = Lists.newArrayList(); coursePaths.put(nodeID, links); } final UserPathLink link = new UserPathLink(String.valueOf(nodeID), "0"); links.add(link); if (lastLink != null) { lastLink.setTarget(String.valueOf(nodeID)); } lastLink = link; } } stopWatch.stop(); this.logger.debug("coursePaths: " + coursePaths.size()); this.logger.debug("Total Fetched log entries: " + (logs.size() + logs.size()) + " log entries." + stopWatch.elapsedTime(TimeUnit.SECONDS)); final Set<UserPathLink> links = Sets.newHashSet(); final JSONObject result = new JSONObject(); final JSONArray nodes = new JSONArray(); final JSONArray edges = new JSONArray(); for (final Entry<Long, List<UserPathLink>> courseEntry : coursePaths.entrySet()) { final JSONObject node = new JSONObject(); node.put("name", courseNodePositions.inverse().get(courseEntry.getKey()).getTitle()); node.put("value", courseEntry.getValue().size()); node.put("group", courses.contains(courseNodePositions.inverse().get(courseEntry.getKey())) ? 1 : 2); nodes.put(node); for (final UserPathLink edge : courseEntry.getValue()) { if (edge.getTarget() == edge.getSource()) { continue; } links.add(edge); } } for (final UserPathLink link : links) { final JSONObject edgeJSON = new JSONObject(); edgeJSON.put("target", link.getTarget()); edgeJSON.put("source", link.getSource()); edges.put(edgeJSON); } this.logger.debug("Nodes: " + nodes.length() + ", Links: " + edges.length() + " / time: " + stopWatch.elapsedTime(TimeUnit.SECONDS)); result.put("nodes", nodes); result.put("links", edges); session.close(); return result; } }