001package net.sf.cpsolver.exam.model;
002
003import java.util.HashMap;
004import java.util.HashSet;
005import java.util.Map;
006import java.util.Set;
007
008import org.dom4j.Element;
009
010import net.sf.cpsolver.coursett.IdConvertor;
011import net.sf.cpsolver.ifs.model.Model;
012import net.sf.cpsolver.ifs.util.DataProperties;
013
014/**
015 * Room sharing model based on a pre-defined list of examination pairs. The relation needs to be populated
016 * using {@link PredefinedExamRoomSharing#addPair(Exam, Exam)} and it is persisted with the solution XML (see
017 * {@link ExamModel#save()}, canShareRoom element for each exam containing a comma separated list of exam ids).
018 * <br>
019 * 
020 * @version ExamTT 1.2 (Examination Timetabling)<br>
021 *          Copyright (C) 2008 - 2012 Tomáš Müller<br>
022 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
023 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
024 * <br>
025 *          This library is free software; you can redistribute it and/or modify
026 *          it under the terms of the GNU Lesser General Public License as
027 *          published by the Free Software Foundation; either version 3 of the
028 *          License, or (at your option) any later version. <br>
029 * <br>
030 *          This library is distributed in the hope that it will be useful, but
031 *          WITHOUT ANY WARRANTY; without even the implied warranty of
032 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
033 *          Lesser General Public License for more details. <br>
034 * <br>
035 *          You should have received a copy of the GNU Lesser General Public
036 *          License along with this library; if not see
037 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
038 */
039public class PredefinedExamRoomSharing extends ExamRoomSharing {
040    private Map<Long, Set<Long>> iSharingMatrix = new HashMap<Long, Set<Long>>();
041    
042    public PredefinedExamRoomSharing(Model<Exam, ExamPlacement> model, DataProperties config) {
043        super(model, config);
044    }
045
046    @Override
047    public boolean canShareRoom(Exam x1, Exam x2) {
048        if (x1.getId() < x2.getId()) {
049            Set<Long> exams = iSharingMatrix.get(x1.getId());
050            return exams != null && exams.contains(x2.getId());
051        } else {
052            Set<Long> exams = iSharingMatrix.get(x2.getId());
053            return exams != null && exams.contains(x1.getId());
054        }
055    }
056    
057    /** Add a pair of exams that are allowed to share a room */
058    public void addPair(Exam x1, Exam x2) {
059        addPair(x1.getId(), x2.getId());
060    }
061    
062    /** Add a pair of exams that are allowed to share a room */
063    public void addPair(Long examId1, Long examId2) {
064        if (examId1 < examId2) {
065            Set<Long> exams = iSharingMatrix.get(examId1);
066            if (exams == null) { exams = new HashSet<Long>(); iSharingMatrix.put(examId1, exams); }
067            exams.add(examId2);
068        } else {
069            Set<Long> exams = iSharingMatrix.get(examId2);
070            if (exams == null) { exams = new HashSet<Long>(); iSharingMatrix.put(examId2, exams); }
071            exams.add(examId1);
072        }        
073    }
074    
075    /** Clear examination pairs */
076    public void clear() {
077        iSharingMatrix.clear();
078    }
079    
080    @Override
081    public void save(Exam exam, Element element, IdConvertor idConvertor) {
082        Set<Long> exams = iSharingMatrix.get(exam.getId());
083        if (exams != null) {
084            String ids = "";
085            for (Long id: exams) {
086                if (!ids.isEmpty()) ids += ",";
087                ids += (idConvertor == null ? id.toString() : idConvertor.convert("exam", id.toString()));
088            }
089            element.addElement("canShareRoom").setText(ids);
090        }
091    }
092    
093    @Override
094    public void load(Exam exam, Element element) {
095        Element canShareRoom = element.element("canShareRoom");
096        if (canShareRoom == null) return;
097        for (String id: canShareRoom.getTextTrim().split(","))
098            addPair(exam.getId(), Long.valueOf(id.trim()));
099    }
100}