    001package org.cpsolver.coursett.model;
    002
    003import java.util.ArrayList;
    004import java.util.Collection;
    005import java.util.Collections;
    006import java.util.Comparator;
    007import java.util.Enumeration;
    008import java.util.HashSet;
    009import java.util.HashMap;
    010import java.util.Iterator;
    011import java.util.List;
    012import java.util.Map;
    013import java.util.Set;
    014import java.util.concurrent.atomic.AtomicReference;
    015import java.util.concurrent.locks.ReentrantReadWriteLock;
    016
    017import org.cpsolver.coursett.Constants;
    018import org.cpsolver.coursett.constraint.ClassLimitConstraint;
    019import org.cpsolver.coursett.constraint.DepartmentSpreadConstraint;
    020import org.cpsolver.coursett.constraint.FlexibleConstraint;
    021import org.cpsolver.coursett.constraint.GroupConstraint;
    022import org.cpsolver.coursett.constraint.IgnoreStudentConflictsConstraint;
    023import org.cpsolver.coursett.constraint.InstructorConstraint;
    024import org.cpsolver.coursett.constraint.JenrlConstraint;
    025import org.cpsolver.coursett.constraint.RoomConstraint;
    026import org.cpsolver.coursett.constraint.SpreadConstraint;
    027import org.cpsolver.coursett.criteria.StudentCommittedConflict;
    028import org.cpsolver.coursett.criteria.StudentConflict;
    029import org.cpsolver.ifs.assignment.Assignment;
    030import org.cpsolver.ifs.assignment.context.AssignmentContext;
    031import org.cpsolver.ifs.assignment.context.VariableWithContext;
    032import org.cpsolver.ifs.constant.ConstantVariable;
    033import org.cpsolver.ifs.model.Constraint;
    034import org.cpsolver.ifs.model.GlobalConstraint;
    035import org.cpsolver.ifs.model.WeakeningConstraint;
    036import org.cpsolver.ifs.util.DistanceMetric;
    037import org.cpsolver.ifs.util.ToolBox;
    038
    039
    040/**
    041 * Lecture (variable).
    042 *
    043 * @author  Tomáš Müller
    044 * @version CourseTT 1.3 (University Course Timetabling)<br>
    045 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
    046 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    047 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    048 * <br>
    049 *          This library is free software; you can redistribute it and/or modify
    050 *          it under the terms of the GNU Lesser General Public License as
    051 *          published by the Free Software Foundation; either version 3 of the
    052 *          License, or (at your option) any later version. <br>
    053 * <br>
    054 *          This library is distributed in the hope that it will be useful, but
    055 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    056 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    057 *          Lesser General Public License for more details. <br>
    058 * <br>
    059 *          You should have received a copy of the GNU Lesser General Public
    060 *          License along with this library; if not see
    061 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
    062 */
    063
    064public class Lecture extends VariableWithContext<Lecture, Placement, Lecture.LectureContext> implements ConstantVariable<Placement> {
    065    private Long iClassId;
    066    private Long iSolverGroupId;
    067    private Long iSchedulingSubpartId;
    068    private String iName;
    069    private Long iDept;
    070    private Long iScheduler;
    071    private List<TimeLocation> iTimeLocations;
    072    private List<RoomLocation> iRoomLocations;
    073    private String iNote = null;
    074
    075    private int iMinClassLimit;
    076    private int iMaxClassLimit;
    077    private float iRoomToLimitRatio;
    078    private int iNrRooms;
    079    private int iOrd;
    080    private double iWeight = 1.0;
    081    private boolean iSplitAttendance = false;
    082
    083    private Set<Student> iStudents = new HashSet<Student>();
    084    private DepartmentSpreadConstraint iDeptSpreadConstraint = null;
    085    private Set<SpreadConstraint> iSpreadConstraints = new HashSet<SpreadConstraint>();
    086    private Set<Constraint<Lecture, Placement>> iWeakeningConstraints = new HashSet<Constraint<Lecture, Placement>>();
    087    private List<InstructorConstraint> iInstructorConstraints = new ArrayList<InstructorConstraint>();
    088    private AtomicReference<Set<Long>> iIgnoreStudentConflictsWith = new AtomicReference<Set<Long>>();
    089    private ClassLimitConstraint iClassLimitConstraint = null;
    090
    091    private Lecture iParent = null;
    092    private HashMap<Long, List<Lecture>> iChildren = null;
    093    private java.util.List<Lecture> iSameSubpartLectures = null;
    094    private Configuration iParentConfiguration = null;
    095
    096    private List<JenrlConstraint> iJenrlConstraints = new ArrayList<JenrlConstraint>();
    097    private HashMap<Lecture, JenrlConstraint> iJenrlConstraintsHash = new HashMap<Lecture, JenrlConstraint>();
    098    private HashMap<Placement, Integer> iCommitedConflicts = new HashMap<Placement, Integer>();
    099    private Set<GroupConstraint> iGroupConstraints = new HashSet<GroupConstraint>();
    100    private Set<GroupConstraint> iHardGroupSoftConstraints = new HashSet<GroupConstraint>();
    101    private Set<GroupConstraint> iCanShareRoomGroupConstraints = new HashSet<GroupConstraint>();
    102    private Set<FlexibleConstraint> iFlexibleGroupConstraints = new HashSet<FlexibleConstraint>();
    103
    104    public boolean iCommitted = false;
    105
    106    public static boolean sSaveMemory = false;
    107    private int iMaxRoomCombinations = -1;
    108
    109    private Integer iCacheMinRoomSize = null;
    110    private Integer iCacheMaxRoomSize = null;
    111    private Integer iCacheMaxAchievableClassLimit = null;
    112
    113    private final ReentrantReadWriteLock iLock = new ReentrantReadWriteLock();
    114
    115    /**
    116     * Constructor
    117     *
    118     * @param id class unique id
    119     * @param solverGroupId solver group unique id
    120     * @param schedulingSubpartId  scheduling subpart unique id
    121     * @param name class name
    122     * @param timeLocations set of time locations
    123     * @param roomLocations set of room location
    124     * @param nrRooms number of rooms into which the class is to be assigned
    125     * @param initialPlacement initial placement
    126     * @param minClassLimit minimum class limit
    127     * @param maxClassLimit maximum class limit
    128     * @param room2limitRatio room ratio
    129     */
    130    public Lecture(Long id, Long solverGroupId, Long schedulingSubpartId, String name,
    131            Collection<TimeLocation> timeLocations, Collection<RoomLocation> roomLocations, int nrRooms,
    132            Placement initialPlacement, int minClassLimit, int maxClassLimit, double room2limitRatio) {
    133        super(initialPlacement);
    134        iClassId = id;
    135        iSchedulingSubpartId = schedulingSubpartId;
    136        iTimeLocations = new ArrayList<TimeLocation>(timeLocations);
    137        iRoomLocations = new ArrayList<RoomLocation>(roomLocations);
    138        iName = name;
    139        iMinClassLimit = minClassLimit;
    140        iMaxClassLimit = maxClassLimit;
    141        iRoomToLimitRatio = (float)room2limitRatio;
    142        iNrRooms = nrRooms;
    143        iSolverGroupId = solverGroupId;
    144    }
    145
    146    public Lecture(Long id, Long solverGroupId, String name) {
    147        super(null);
    148        iClassId = id;
    149        iSolverGroupId = solverGroupId;
    150        iName = name;
    151    }
    152
    153    public Long getSolverGroupId() {
    154        return iSolverGroupId;
    155    }
    156
    157    /**
    158     * Add active jenrl constraint (active mean that there is at least one
    159     * student between its classes)
    160     * @param assignment current assignment
    161     * @param constr an active jenrl constraint
    162     */
    163    public void addActiveJenrl(Assignment<Lecture, Placement> assignment, JenrlConstraint constr) {
    164        getContext(assignment).addActiveJenrl(constr);
    165    }
    166
    167    /**
    168     * Active jenrl constraints (active mean that there is at least one student
    169     * between its classes)
    170     * @param assignment current assignment
    171     * @return set of active jenrl constraints
    172     */
    173    public Set<JenrlConstraint> activeJenrls(Assignment<Lecture, Placement> assignment) {
    174        return getContext(assignment).activeJenrls();
    175    }
    176
    177    /**
    178     * Remove active jenrl constraint (active mean that there is at least one
    179     * student between its classes)
    180     * @param assignment current assignment
    181     * @param constr an active jenrl constraint
    182     */
    183    public void removeActiveJenrl(Assignment<Lecture, Placement> assignment, JenrlConstraint constr) {
    184        getContext(assignment).removeActiveJenrl(constr);
    185    }
    186
    187    /** Class id
    188     * @return class unique id
    189     **/
    190    public Long getClassId() {
    191        return iClassId;
    192    }
    193
    194    /**
    195     * Scheduling subpart id
    196     * @return scheduling subpart unique id
    197     */
    198    public Long getSchedulingSubpartId() {
    199        return iSchedulingSubpartId;
    200    }
    201
    202    /** Class name */
    203    @Override
    204    public String getName() {
    205        return iName;
    206    }
    207
    208    /** Class id */
    209    @Override
    210    public long getId() {
    211        return iClassId.longValue();
    212    }
    213
    214    /** Instructor name
    215     * @return list of instructor names
    216     **/
    217    public List<String> getInstructorNames() {
    218        List<String> ret = new ArrayList<String>();
    219        for (InstructorConstraint ic : iInstructorConstraints) {
    220            ret.add(ic.getName());
    221        }
    222        return ret;
    223    }
    224
    225    public String getInstructorName() {
    226        StringBuffer sb = new StringBuffer();
    227        for (InstructorConstraint ic : iInstructorConstraints) {
    228            if (sb.length() > 0)
    229                sb.append(", ");
    230            sb.append(ic.getName());
    231        }
    232        return sb.toString();
    233    }
    234
    235    /** List of enrolled students
    236     * @return list of enrolled students
    237     **/
    238    public Set<Student> students() {
    239        return iStudents;
    240    }
    241
    242    /**
    243     * Total weight of all enrolled students
    244     * @return sum of {@link Student#getOfferingWeight(Configuration)} of each enrolled student
    245     */
    246    public double nrWeightedStudents() {
    247        double w = 0.0;
    248        for (Student s : iStudents) {
    249            w += s.getOfferingWeight(getConfiguration());
    250        }
    251        return w;
    252    }
    253
    254    /** Add an enrolled student
    255     * @param assignment current assignment
    256     * @param student a student to add
    257     **/
    258    public void addStudent(Assignment<Lecture, Placement> assignment, Student student) {
    259        if (!iStudents.add(student))
    260            return;
    261        Placement value = (assignment == null ? null : assignment.getValue(this));
    262        if (value != null && getModel() != null)
    263            getModel().getCriterion(StudentCommittedConflict.class).inc(assignment, student.countConflictPlacements(value));
    264        iLock.writeLock().lock();
    265        iCommitedConflicts.clear();
    266        iLock.writeLock().unlock();
    267    }
    268
    269    /**
    270     * Remove an enrolled student
    271     * @param assignment current assignment
    272     * @param student a student to remove
    273     */
    274    public void removeStudent(Assignment<Lecture, Placement> assignment, Student student) {
    275        if (!iStudents.remove(student))
    276            return;
    277        Placement value = (assignment == null ? null : assignment.getValue(this));
    278        if (value != null && getModel() != null)
    279            getModel().getCriterion(StudentCommittedConflict.class).inc(assignment, -student.countConflictPlacements(value));
    280        iLock.writeLock().lock();
    281        iCommitedConflicts.clear();
    282        iLock.writeLock().unlock();
    283    }
    284
    285    /** Returns true if the given student is enrolled
    286     * @param student a student
    287     * @return true if the given student is enrolled in this class
    288     **/
    289    public boolean hasStudent(Student student) {
    290        return iStudents.contains(student);
    291    }
    292
    293    /** Set of lectures of the same class (only section is different)
    294     * @param sameSubpartLectures list of lectures of the same scheduling subpart
    295     **/
    296    public void setSameSubpartLectures(List<Lecture> sameSubpartLectures) {
    297        iSameSubpartLectures = sameSubpartLectures;
    298    }
    299
    300    /** Set of lectures of the same class (only section is different)
    301     * @return list of lectures of the same scheduling subpart
    302     **/
    303    public List<Lecture> sameSubpartLectures() {
    304        return iSameSubpartLectures;
    305    }
    306
    307    /** List of students enrolled in this class as well as in the given class
    308     * @param lecture a lecture
    309     * @return a set of students that are enrolled in both lectures
    310     **/
    311    public Set<Student> sameStudents(Lecture lecture) {
    312        JenrlConstraint jenrl = jenrlConstraint(lecture);
    313        return (jenrl == null ? new HashSet<Student>() : jenrl.getStudents());
    314    }
    315
    316    /** List of students of this class in conflict with the given assignment
    317     * @param assignment current assignment
    318     * @param value given placement
    319     * @return list of student conflicts
    320     **/
    321    public Set<Student> conflictStudents(Assignment<Lecture, Placement> assignment, Placement value) {
    322        if (value == null)
    323            return new HashSet<Student>();
    324        if (value.equals(assignment.getValue(this)))
    325            return conflictStudents(assignment);
    326        Set<Student> ret = new HashSet<Student>();
    327        for (JenrlConstraint jenrl : jenrlConstraints()) {
    328            if (jenrl.jenrl(assignment, this, value) > 0)
    329                ret.addAll(sameStudents(jenrl.another(this)));
    330        }
    331        return ret;
    332    }
    333
    334    /**
    335     * List of students of this class which are in conflict with any other
    336     * assignment
    337     * @param assignment current assignment
    338     * @return list of student conflicts
    339     */
    340    public Set<Student> conflictStudents(Assignment<Lecture, Placement> assignment) {
    341        Set<Student> ret = new HashSet<Student>();
    342        Placement placement = assignment.getValue(this);
    343        if (placement == null)
    344            return ret;
    345        for (JenrlConstraint jenrl : activeJenrls(assignment)) {
    346            ret.addAll(sameStudents(jenrl.another(this)));
    347        }
    348        for (Student student : students()) {
    349            if (student.countConflictPlacements(placement) > 0)
    350                ret.add(student);
    351        }
    352        return ret;
    353    }
    354
    355    /**
    356     * Lectures different from this one, where it is student conflict of the
    357     * given student between this and the lecture
    358     * @param assignment current assignment
    359     * @param student a student
    360     * @return list of lectures with a student conflict
    361     */
    362    public List<Lecture> conflictLectures(Assignment<Lecture, Placement> assignment, Student student) {
    363        List<Lecture> ret = new ArrayList<Lecture>();
    364        if (assignment.getValue(this) == null)
    365            return ret;
    366        for (JenrlConstraint jenrl : activeJenrls(assignment)) {
    367            Lecture lect = jenrl.another(this);
    368            if (lect.students().contains(student))
    369                ret.add(lect);
    370        }
    371        return ret;
    372    }
    373
    374    /** True if this lecture is in a student conflict with the given student
    375     * @param assignment current assignment
    376     * @param student a student
    377     * @return number of other lectures with a student conflict
    378     **/
    379    public int isInConflict(Assignment<Lecture, Placement> assignment, Student student) {
    380        if (assignment.getValue(this) == null)
    381            return 0;
    382        int ret = 0;
    383        for (JenrlConstraint jenrl : activeJenrls(assignment)) {
    384            Lecture lect = jenrl.another(this);
    385            if (lect.students().contains(student))
    386                ret++;
    387        }
    388        return ret;
    389    }
    390
    391    private boolean isCacheDomain() {
    392        return isCommitted() || (!sSaveMemory && (iNrRooms <= 1 || getMaxRoomCombinations() <= 0 || ToolBox.binomial(iRoomLocations.size(), iNrRooms) <= getMaxRoomCombinations()));
    393    }
    394
    395    /** Domain -- all combinations of room and time locations
    396     * @param assignment current assignment
    397     * @param allowBreakHard breaking of hard constraints is allowed
    398     * @return list of possible placements
    399     **/
    400    public List<Placement> computeValues(Assignment<Lecture, Placement> assignment, boolean allowBreakHard) {
    401        List<Placement> values = new ArrayList<Placement>(iRoomLocations.size() * iTimeLocations.size());
    402        for (TimeLocation timeLocation : iTimeLocations) {
    403            if (!allowBreakHard && Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(timeLocation.getPreference())))
    404                continue;
    405            if (timeLocation.getPreference() > 500)
    406                continue;
    407            boolean notAvailable = false;
    408            for (InstructorConstraint ic : getInstructorConstraints()) {
    409                if (!ic.isAvailable(this, timeLocation) && ic.isHard()) {
    410                    notAvailable = true;
    411                    break;
    412                }
    413            }
    414            if (notAvailable)
    415                continue;
    416            if (iNrRooms == 0) {
    417                Placement p = new Placement(this, timeLocation, (RoomLocation) null);
    418                for (InstructorConstraint ic : getInstructorConstraints()) {
    419                    if (!ic.isAvailable(this, p) && ic.isHard()) {
    420                        notAvailable = true;
    421                        break;
    422                    }
    423                }
    424                if (notAvailable)
    425                    continue;
    426                p.setVariable(this);
    427                if (sSaveMemory && !isValid(p))
    428                    continue;
    429                if (getInitialAssignment() != null && p.equals(getInitialAssignment()))
    430                    setInitialAssignment(p);
    431                // if (getAssignment() != null && getAssignment().equals(p)) iValue = getAssignment();
    432                if (getBestAssignment() != null && getBestAssignment().equals(p))
    433                    setBestAssignment(p, getBestAssignmentIteration());
    434                values.add(p);
    435            } else if (iNrRooms == 1) {
    436                rooms: for (RoomLocation roomLocation : iRoomLocations) {
    437                    if (!allowBreakHard && Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(roomLocation.getPreference()))) continue;
    438                    if (roomLocation.getPreference() > 500) continue;
    439                    if (roomLocation.getRoomConstraint() != null && !roomLocation.getRoomConstraint().isAvailable(this, timeLocation, getScheduler())) continue;
    440                    Placement p = new Placement(this, timeLocation, roomLocation);
    441                    p.setVariable(this);
    442                    for (InstructorConstraint ic : getInstructorConstraints())
    443                        if (!ic.isAvailable(this, p) && ic.isHard()) continue rooms;
    444                    if (sSaveMemory && !isValid(p)) continue;
    445                    if (getInitialAssignment() != null && p.equals(getInitialAssignment())) setInitialAssignment(p);
    446                    if (getBestAssignment() != null && getBestAssignment().equals(p)) setBestAssignment(p, getBestAssignmentIteration());
    447                    values.add(p);
    448                }
    449            } else {
    450                if (getMaxRoomCombinations() > 0 && ToolBox.binomial(iRoomLocations.size(), iNrRooms) > getMaxRoomCombinations()) {
    451                    if (getInitialAssignment() != null && getInitialAssignment().getNrRooms() == getNrRooms()) {
    452                        boolean av = true;
    453                        for (RoomLocation room: getInitialAssignment().getRoomLocations()) {
    454                            if (room.getRoomConstraint() != null && !room.getRoomConstraint().isAvailable(this, timeLocation, getScheduler())) { av = false; break; }
    455                            if (room.getMinPreference() > 500) { av = false; break; }
    456                            if (!allowBreakHard && Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(room.getMinPreference()))) { av = false; break; }
    457                        }
    458                        Placement p = new Placement(this, timeLocation, new ArrayList<RoomLocation>(getInitialAssignment().getRoomLocations()));
    459                        if (!allowBreakHard && p.isRoomProhibited()) av = false;
    460                        for (InstructorConstraint ic : getInstructorConstraints())
    461                            if (!ic.isAvailable(this, p) && ic.isHard()) { av = false; break; }
    462                        if (av && !isTooSmall(p) && !checkParents(p) && (!sSaveMemory || isValid(p))) {
    463                            p.setVariable(this);
    464                            if (p.equals(getInitialAssignment())) setInitialAssignment(p);
    465                            if (getBestAssignment() != null && getBestAssignment().equals(p)) setBestAssignment(p, getBestAssignmentIteration());
    466                            values.add(p);
    467                        }
    468                    }
    469                    List<RoomLocation> available = new ArrayList<RoomLocation>(iRoomLocations.size());
    470                    List<RoomLocation> other = new ArrayList<RoomLocation>(iRoomLocations.size());
    471                    rooms: for (RoomLocation room: iRoomLocations) {
    472                        if (room.getRoomConstraint() != null && !room.getRoomConstraint().isAvailable(this, timeLocation, getScheduler())) continue;
    473                        if (room.getMinPreference() > 500) continue;
    474                        if (!allowBreakHard && Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(room.getMinPreference()))) continue;
    475                        for (InstructorConstraint ic : getInstructorConstraints())
    476                            if (!ic.isAvailable(this, new Placement(this, timeLocation, room)) && ic.isHard()) continue rooms;
    477                        if (assignment != null && room.getRoomConstraint() != null && !room.getRoomConstraint().getContext(assignment).inConflict(this, timeLocation) &&
    478                            !Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(room.getMinPreference()))) {
    479                            available.add(room);
    480                        } else {
    481                            other.add(room);
    482                        }
    483                    }
    484                    if (available.size() + other.size() < iNrRooms) continue;
    485                    for (Enumeration<Collection<RoomLocation>> e = ToolBox.sample(available, other, iNrRooms, isSplitAttendance() ? -1 : getMaxRoomCombinations()); e.hasMoreElements(); ) {
    486                        Collection<RoomLocation> rm = e.nextElement();
    487                        if (isTooSmall(rm)) continue;
    488                        Placement p = new Placement(this, timeLocation, new ArrayList<RoomLocation>(rm));
    489                        if (!checkParents(p)) continue;
    490                        if (!allowBreakHard && p.isRoomProhibited()) continue;
    491                        if (getInitialAssignment() != null && p.sameRooms(getInitialAssignment())) continue;
    492                        p.setVariable(this);
    493                        if (sSaveMemory && !isValid(p)) continue;
    494                        if (getBestAssignment() != null && getBestAssignment().equals(p)) setBestAssignment(p, getBestAssignmentIteration());
    495                        values.add(p);
    496                        if (values.size() >= getMaxRoomCombinations()) break;
    497                    }
    498                } else {
    499                    List<RoomLocation> rooms = new ArrayList<RoomLocation>(iRoomLocations.size());
    500                    rooms: for (RoomLocation room: iRoomLocations) {
    501                        if (!allowBreakHard && Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(room.getMinPreference()))) continue;
    502                        if (room.getMinPreference() > 500) continue;
    503                        if (room.getRoomConstraint() != null && !room.getRoomConstraint().isAvailable(this, timeLocation, getScheduler())) continue;
    504                        for (InstructorConstraint ic : getInstructorConstraints())
    505                            if (!ic.isAvailable(this, new Placement(this, timeLocation, room)) && ic.isHard()) continue rooms;
    506                        rooms.add(room);
    507                    }
    508                    if (rooms.size() < iNrRooms) continue;
    509                    for (Enumeration<Collection<RoomLocation>> e = ToolBox.permutations(rooms, iNrRooms); e.hasMoreElements(); ) {
    510                        Collection<RoomLocation> rm = e.nextElement();
    511                        if (isTooSmall(rm)) continue;
    512                        Placement p = new Placement(this, timeLocation, new ArrayList<RoomLocation>(rm));
    513                        if (!checkParents(p)) continue;
    514                        if (!allowBreakHard && p.isRoomProhibited()) continue;
    515                        p.setVariable(this);
    516                        if (sSaveMemory && !isValid(p)) continue;
    517                        if (getInitialAssignment() != null && p.equals(getInitialAssignment())) setInitialAssignment(p);
    518                        if (getBestAssignment() != null && getBestAssignment().equals(p)) setBestAssignment(p, getBestAssignmentIteration());
    519                        values.add(p);
    520                    }
    521                }
    522            }
    523        }
    524        return values;
    525    }
    526
    527    public void clearValueCache() {
    528        super.setValues(null);
    529    }
    530
    531    /** All values */
    532    @Override
    533    public List<Placement> values(Assignment<Lecture, Placement> assignment) {
    534        if (super.values(assignment) == null) {
    535            if (getInitialAssignment() != null && iTimeLocations.size() == 1 && iRoomLocations.size() == getNrRooms()) {
    536                List<Placement> values = new ArrayList<Placement>(1);
    537                values.add(getInitialAssignment());
    538                setValues(values);
    539                return values;
    540            } else if (isCacheDomain()) {
    541                List<Placement> values = computeValues(null, allowBreakHard());
    542                setValues(values);
    543                return values;
    544            } else {
    545                return computeValues(assignment, allowBreakHard());
    546            }
    547        } else {
    548            return super.values(assignment);
    549        }
    550    }
    551
    552    @Override
    553    public boolean equals(Object o) {
    554        if (o == null || !(o instanceof Lecture))
    555            return false;
    556        return getClassId().equals(((Lecture) o).getClassId());
    557    }
    558
    559    /** Best time preference of this lecture */
    560    private Double iBestTimePreferenceCache = null;
    561
    562    public double getBestTimePreference() {
    563        if (iBestTimePreferenceCache == null) {
    564            double ret = Double.MAX_VALUE;
    565            for (TimeLocation time : iTimeLocations) {
    566                ret = Math.min(ret, time.getNormalizedPreference());
    567            }
    568            iBestTimePreferenceCache = Double.valueOf(ret);
    569        }
    570        return iBestTimePreferenceCache.doubleValue();
    571    }
    572
    573    /** Best room preference of this lecture
    574     * @return best room preference
    575     **/
    576    public int getBestRoomPreference() {
    577        int ret = Integer.MAX_VALUE;
    578        for (RoomLocation room : iRoomLocations) {
    579            ret = Math.min(ret, room.getMinPreference());
    580        }
    581        return ret;
    582    }
    583
    584    /**
    585     * Number of student conflicts caused by the given assignment of this
    586     * lecture
    587     * @param assignment current assignment
    588     * @param value a placement
    589     * @return number of student conflicts if assigned
    590     */
    591    public int countStudentConflicts(Assignment<Lecture, Placement> assignment, Placement value) {
    592        int studentConflictsSum = 0;
    593        for (JenrlConstraint jenrl : jenrlConstraints()) {
    594            studentConflictsSum += jenrl.jenrl(assignment, this, value);
    595        }
    596        return studentConflictsSum;
    597    }
    598
    599    public int countStudentConflictsOfTheSameProblem(Assignment<Lecture, Placement> assignment, Placement value) {
    600        int studentConflictsSum = 0;
    601        for (JenrlConstraint jenrl : jenrlConstraints()) {
    602            if (!jenrl.isOfTheSameProblem())
    603                continue;
    604            studentConflictsSum += jenrl.jenrl(assignment, this, value);
    605        }
    606        return studentConflictsSum;
    607    }
    608
    609    public int countHardStudentConflicts(Assignment<Lecture, Placement> assignment, Placement value) {
    610        int studentConflictsSum = 0;
    611        if (!isSingleSection())
    612            return 0;
    613        for (JenrlConstraint jenrl : jenrlConstraints()) {
    614            if (!jenrl.areStudentConflictsHard())
    615                continue;
    616            studentConflictsSum += jenrl.jenrl(assignment, this, value);
    617        }
    618        return studentConflictsSum;
    619    }
    620
    621    public int countCommittedStudentConflictsOfTheSameProblem(Assignment<Lecture, Placement> assignment, Placement value) {
    622        int studentConflictsSum = 0;
    623        for (JenrlConstraint jenrl : jenrlConstraints()) {
    624            if (!jenrl.isOfTheSameProblem())
    625                continue;
    626            if (!jenrl.areStudentConflictsCommitted())
    627                continue;
    628            studentConflictsSum += jenrl.jenrl(assignment, this, value);
    629        }
    630        return studentConflictsSum;
    631    }
    632
    633    public int countCommittedStudentConflicts(Assignment<Lecture, Placement> assignment, Placement value) {
    634        int studentConflictsSum = 0;
    635        for (JenrlConstraint jenrl : jenrlConstraints()) {
    636            if (!jenrl.areStudentConflictsCommitted())
    637                continue;
    638            studentConflictsSum += jenrl.jenrl(assignment, this, value);
    639        }
    640        return studentConflictsSum;
    641    }
    642
    643    public int countHardStudentConflictsOfTheSameProblem(Assignment<Lecture, Placement> assignment, Placement value) {
    644        int studentConflictsSum = 0;
    645        for (JenrlConstraint jenrl : jenrlConstraints()) {
    646            if (!jenrl.isOfTheSameProblem())
    647                continue;
    648            if (!jenrl.areStudentConflictsHard())
    649                continue;
    650            studentConflictsSum += jenrl.jenrl(assignment, this, value);
    651        }
    652        return studentConflictsSum;
    653    }
    654
    655    public int countDistanceStudentConflicts(Assignment<Lecture, Placement> assignment, Placement value) {
    656        int studentConflictsSum = 0;
    657        for (JenrlConstraint jenrl : jenrlConstraints()) {
    658            if (!jenrl.areStudentConflictsDistance(assignment, value))
    659                continue;
    660            studentConflictsSum += jenrl.jenrl(assignment, this, value);
    661        }
    662        return studentConflictsSum;
    663    }
    664
    665    public int countDistanceStudentConflictsOfTheSameProblem(Assignment<Lecture, Placement> assignment, Placement value) {
    666        int studentConflictsSum = 0;
    667        for (JenrlConstraint jenrl : jenrlConstraints()) {
    668            if (!jenrl.isOfTheSameProblem())
    669                continue;
    670            if (!jenrl.areStudentConflictsDistance(assignment, value))
    671                continue;
    672            studentConflictsSum += jenrl.jenrl(assignment, this, value);
    673        }
    674        return studentConflictsSum;
    675    }
    676
    677    private DistanceMetric getDistanceMetric() {
    678        return ((TimetableModel)getModel()).getDistanceMetric();
    679    }
    680
    681    private int getStudentWorkDayLimit() {
    682        return ((TimetableModel)getModel()).getStudentWorkDayLimit();
    683    }
    684
    685    /**
    686     * Number of student conflicts caused by the initial assignment of this
    687     * lecture
    688     * @return number of student conflicts with the initial assignment of this class
    689     */
    690    public int countInitialStudentConflicts() {
    691        Placement value = getInitialAssignment();
    692        if (value == null)
    693            return 0;
    694        int studentConflictsSum = 0;
    695        for (JenrlConstraint jenrl : jenrlConstraints()) {
    696            Lecture another = jenrl.another(this);
    697            if (another.getInitialAssignment() != null)
    698                if (JenrlConstraint.isInConflict(value, another.getInitialAssignment(), getDistanceMetric(), getStudentWorkDayLimit()))
    699                    studentConflictsSum += jenrl.getJenrl();
    700        }
    701        return studentConflictsSum;
    702    }
    703
    704    /**
    705     * Table of student conflicts caused by the initial assignment of this
    706     * lecture in format (another lecture, number)
    707     * @return table of student conflicts with the initial assignment of this class
    708     */
    709    public Map<Lecture, Long> getInitialStudentConflicts() {
    710        Placement value = getInitialAssignment();
    711        if (value == null)
    712            return null;
    713        Map<Lecture, Long> ret = new HashMap<Lecture, Long>();
    714        for (JenrlConstraint jenrl : jenrlConstraints()) {
    715            Lecture another = jenrl.another(this);
    716            if (another.getInitialAssignment() != null)
    717                if (JenrlConstraint.isInConflict(value, another.getInitialAssignment(), getDistanceMetric(), getStudentWorkDayLimit()))
    718                    ret.put(another, jenrl.getJenrl());
    719        }
    720        return ret;
    721    }
    722
    723    /**
    724     * List of student conflicts caused by the initial assignment of this
    725     * lecture
    726     * @return a set of students in a conflict with the initial assignment of this class
    727     */
    728    public Set<Student> initialStudentConflicts() {
    729        Placement value = getInitialAssignment();
    730        if (value == null)
    731            return null;
    732        HashSet<Student> ret = new HashSet<Student>();
    733        for (JenrlConstraint jenrl : jenrlConstraints()) {
    734            Lecture another = jenrl.another(this);
    735            if (another.getInitialAssignment() != null)
    736                if (JenrlConstraint.isInConflict(value, another.getInitialAssignment(), getDistanceMetric(), getStudentWorkDayLimit()))
    737                    ret.addAll(sameStudents(another));
    738        }
    739        return ret;
    740    }
    741
    742    @Override
    743    public void addContstraint(Constraint<Lecture, Placement> constraint) {
    744        super.addContstraint(constraint);
    745
    746        if (constraint instanceof WeakeningConstraint)
    747            iWeakeningConstraints.add(constraint);
    748
    749        if (constraint instanceof FlexibleConstraint)
    750            iFlexibleGroupConstraints.add((FlexibleConstraint) constraint);
    751
    752        if (constraint instanceof JenrlConstraint) {
    753            JenrlConstraint jenrl = (JenrlConstraint) constraint;
    754            Lecture another = jenrl.another(this);
    755            if (another != null) {
    756                iJenrlConstraints.add(jenrl);
    757                another.iJenrlConstraints.add(jenrl);
    758                iJenrlConstraintsHash.put(another, (JenrlConstraint) constraint);
    759                another.iJenrlConstraintsHash.put(this, (JenrlConstraint) constraint);
    760            }
    761        } else if (constraint instanceof DepartmentSpreadConstraint)
    762            iDeptSpreadConstraint = (DepartmentSpreadConstraint) constraint;
    763        else if (constraint instanceof SpreadConstraint)
    764            iSpreadConstraints.add((SpreadConstraint) constraint);
    765        else if (constraint instanceof InstructorConstraint) {
    766            InstructorConstraint ic = (InstructorConstraint) constraint;
    767            if (ic.getResourceId() != null && ic.getResourceId().longValue() > 0)
    768                iInstructorConstraints.add(ic);
    769        } else if (constraint instanceof ClassLimitConstraint)
    770            iClassLimitConstraint = (ClassLimitConstraint) constraint;
    771        else if (constraint instanceof GroupConstraint) {
    772            GroupConstraint gc = (GroupConstraint) constraint;
    773            if (gc.canShareRoom()) {
    774                iCanShareRoomGroupConstraints.add((GroupConstraint) constraint);
    775            } else {
    776                iGroupConstraints.add((GroupConstraint) constraint);
    777                if (Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(gc.getPreference()))
    778                        || Constants.sPreferenceRequired.equals(Constants
    779                                .preferenceLevel2preference(gc.getPreference())))
    780                    iHardGroupSoftConstraints.add((GroupConstraint) constraint);
    781            }
    782        }
    783    }
    784
    785    @Override
    786    public void removeContstraint(Constraint<Lecture, Placement> constraint) {
    787        super.removeContstraint(constraint);
    788
    789        if (constraint instanceof WeakeningConstraint)
    790            iWeakeningConstraints.remove(constraint);
    791
    792        if (constraint instanceof FlexibleConstraint)
    793            iFlexibleGroupConstraints.remove(constraint);
    794
    795        if (constraint instanceof JenrlConstraint) {
    796            JenrlConstraint jenrl = (JenrlConstraint) constraint;
    797            Lecture another = jenrl.another(this);
    798            if (another != null) {
    799                iJenrlConstraints.remove(jenrl);
    800                another.iJenrlConstraints.remove(jenrl);
    801                iJenrlConstraintsHash.remove(another);
    802                another.iJenrlConstraintsHash.remove(this);
    803            }
    804        } else if (constraint instanceof GroupConstraint) {
    805            iCanShareRoomGroupConstraints.remove(constraint);
    806            iHardGroupSoftConstraints.remove(constraint);
    807            iGroupConstraints.remove(constraint);
    808        } else if (constraint instanceof DepartmentSpreadConstraint)
    809            iDeptSpreadConstraint = null;
    810        else if (constraint instanceof SpreadConstraint)
    811            iSpreadConstraints.remove(constraint);
    812        else if (constraint instanceof InstructorConstraint)
    813            iInstructorConstraints.remove(constraint);
    814        else if (constraint instanceof ClassLimitConstraint)
    815            iClassLimitConstraint = null;
    816    }
    817
    818    /** All JENRL constraints of this lecture
    819     * @param another another class
    820     * @return a join enrollment constraint between this and the given class, if there is one
    821     **/
    822    public JenrlConstraint jenrlConstraint(Lecture another) {
    823        /*
    824         * for (Enumeration e=iJenrlConstraints.elements();e.hasMoreElements();)
    825         * { JenrlConstraint jenrl = (JenrlConstraint)e.nextElement(); if
    826         * (jenrl.another(this).equals(another)) return jenrl; } return null;
    827         */
    828        return iJenrlConstraintsHash.get(another);
    829    }
    830
    831    /** All JENRL constraints of this lecture
    832     * @return list of all join enrollment constraints in which this lecture is involved
    833     **/
    834    public List<JenrlConstraint> jenrlConstraints() {
    835        return iJenrlConstraints;
    836    }
    837
    838    public int minClassLimit() {
    839        return iMinClassLimit;
    840    }
    841
    842    public int maxClassLimit() {
    843        return iMaxClassLimit;
    844    }
    845
    846    public int maxAchievableClassLimit() {
    847        iLock.readLock().lock();
    848        try {
    849            if (iCacheMaxAchievableClassLimit != null) return iCacheMaxAchievableClassLimit.intValue();
    850        } finally {
    851            iLock.readLock().unlock();
    852        }
    853        iLock.writeLock().lock();
    854        try {
    855            if (iCacheMaxAchievableClassLimit != null) return iCacheMaxAchievableClassLimit.intValue();
    856
    857            int maxAchievableClassLimit = Math.min(maxClassLimit(), (int) Math.floor(maxRoomSize() / roomToLimitRatio()));
    858
    859            if (hasAnyChildren()) {
    860
    861                for (Long subpartId: getChildrenSubpartIds()) {
    862                    int maxAchievableChildrenLimit = 0;
    863
    864                    for (Lecture child : getChildren(subpartId)) {
    865                        maxAchievableChildrenLimit += child.maxAchievableClassLimit();
    866                    }
    867
    868                    maxAchievableClassLimit = Math.min(maxAchievableClassLimit, maxAchievableChildrenLimit);
    869                }
    870            }
    871
    872            maxAchievableClassLimit = Math.max(minClassLimit(), maxAchievableClassLimit);
    873            iCacheMaxAchievableClassLimit = Integer.valueOf(maxAchievableClassLimit);
    874            return maxAchievableClassLimit;
    875        } finally {
    876            iLock.writeLock().unlock();
    877        }
    878    }
    879
    880    public int classLimit(Assignment<Lecture, Placement> assignment) {
    881        if (minClassLimit() == maxClassLimit())
    882            return minClassLimit();
    883        return classLimit(assignment, null, null);
    884    }
    885
    886    public int classLimit(Assignment<Lecture, Placement> assignment, Placement value, Set<Placement> conflicts) {
    887        Placement a = (assignment == null ? null : assignment.getValue(this));
    888        if (value != null && value.variable().equals(this))
    889            a = value;
    890        if (conflicts != null && a != null && conflicts.contains(a))
    891            a = null;
    892        int classLimit = (a == null ? maxAchievableClassLimit() : Math.min(maxClassLimit(), (int) Math.floor(a.getRoomSize() / roomToLimitRatio())));
    893
    894        if (!hasAnyChildren())
    895            return classLimit;
    896
    897        for (Long subpartId: getChildrenSubpartIds()) {
    898            int childrenClassLimit = 0;
    899
    900            for (Lecture child : getChildren(subpartId)) {
    901                childrenClassLimit += child.classLimit(assignment, value, conflicts);
    902            }
    903
    904            classLimit = Math.min(classLimit, childrenClassLimit);
    905        }
    906
    907        return Math.max(minClassLimit(), classLimit);
    908    }
    909
    910    public double roomToLimitRatio() {
    911        return iRoomToLimitRatio;
    912    }
    913
    914    public int minRoomUse() {
    915        return iNrRooms == 0 ? 0 : Math.round(iMinClassLimit * iRoomToLimitRatio);
    916    }
    917
    918    public int maxRoomUse() {
    919        return iNrRooms == 0 ? 0 : Math.round(iMaxClassLimit * iRoomToLimitRatio);
    920    }
    921
    922    @Override
    923    public String toString() {
    924        return getName();
    925    }
    926
    927    /** Controlling Course Offering Department
    928     * @return department unique id
    929     **/
    930    public Long getDepartment() {
    931        return iDept;
    932    }
    933
    934    /** Controlling Course Offering Department
    935     * @param dept department unique id
    936     **/
    937    public void setDepartment(Long dept) {
    938        iDept = dept;
    939    }
    940
    941    /** Scheduler (Managing Department)
    942     * @return solver group unique id
    943     **/
    944    public Long getScheduler() {
    945        return iScheduler;
    946    }
    947
    948    /** Scheduler (Managing Department)
    949     * @param scheduler solver group unique id
    950     **/
    951    public void setScheduler(Long scheduler) {
    952        iScheduler = scheduler;
    953    }
    954
    955    /** Departmental spreading constraint
    956     * @return department spread constraint of this class, if any
    957     **/
    958    public DepartmentSpreadConstraint getDeptSpreadConstraint() {
    959        return iDeptSpreadConstraint;
    960    }
    961
    962    /** Instructor constraint
    963     * @return instructors of this class
    964     **/
    965    public List<InstructorConstraint> getInstructorConstraints() {
    966        return iInstructorConstraints;
    967    }
    968
    969    public ClassLimitConstraint getClassLimitConstraint() {
    970        return iClassLimitConstraint;
    971    }
    972
    973    public Set<SpreadConstraint> getSpreadConstraints() {
    974        return iSpreadConstraints;
    975    }
    976
    977    public Set<FlexibleConstraint> getFlexibleGroupConstraints() {
    978        return iFlexibleGroupConstraints;
    979    }
    980
    981    public Set<Constraint<Lecture, Placement>> getWeakeningConstraints() {
    982        return iWeakeningConstraints;
    983    }
    984
    985    /** All room locations
    986     * @return possible rooms of this class
    987     **/
    988    public List<RoomLocation> roomLocations() {
    989        return iRoomLocations;
    990    }
    991
    992    /** All time locations
    993     * @return possible times of this class
    994     **/
    995    public List<TimeLocation> timeLocations() {
    996        return iTimeLocations;
    997    }
    998
    999    public int nrTimeLocations() {
    1000        int ret = 0;
    1001        for (TimeLocation time : iTimeLocations) {
    1002            if (!Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(time.getPreference())))
    1003                ret++;
    1004        }
    1005        return ret;
    1006    }
    1007
    1008    public int nrRoomLocations() {
    1009        int ret = 0;
    1010        for (RoomLocation room : iRoomLocations) {
    1011            if (!Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(room.getMinPreference())))
    1012                ret++;
    1013        }
    1014        return ret;
    1015    }
    1016
    1017    public long nrValues() {
    1018        int nrTimes = 0;
    1019        for (TimeLocation time: timeLocations())
    1020            if (!Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(time.getPreference())))
    1021                nrTimes ++;
    1022        int nrRooms = 0;
    1023        for (RoomLocation room : iRoomLocations)
    1024            if (!Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(room.getMinPreference())))
    1025                nrRooms ++;
    1026        long estNrValues = nrTimes;
    1027        if (getNrRooms() > 1 && getMaxRoomCombinations() > 0)
    1028            estNrValues *= Math.min(getMaxRoomCombinations(), ToolBox.binomial(nrRooms, getNrRooms()));
    1029        else
    1030            estNrValues *= ToolBox.binomial(nrRooms, getNrRooms());
    1031        return estNrValues;
    1032    }
    1033
    1034    public int nrValues(TimeLocation time) {
    1035        int ret = 0;
    1036        for (RoomLocation room : iRoomLocations) {
    1037            if (!Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(room.getMinPreference()))
    1038                    && (room.getRoomConstraint() == null || room.getRoomConstraint().isAvailable(this, time, getScheduler())))
    1039                ret++;
    1040        }
    1041        return ret;
    1042    }
    1043
    1044    public int nrValues(RoomLocation room) {
    1045        int ret = 0;
    1046        for (TimeLocation time : iTimeLocations) {
    1047            if (!Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(time.getPreference()))
    1048                    && (room.getRoomConstraint() == null || room.getRoomConstraint().isAvailable(this, time,getScheduler())))
    1049                ret++;
    1050        }
    1051        return ret;
    1052    }
    1053
    1054    public int nrValues(List<RoomLocation> rooms) {
    1055        int ret = 0;
    1056        for (TimeLocation time : iTimeLocations) {
    1057            boolean available = true;
    1058            for (RoomLocation room : rooms) {
    1059                if (Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(time.getPreference()))
    1060                        || (room.getRoomConstraint() != null && !room.getRoomConstraint().isAvailable(this, time,
    1061                                getScheduler())))
    1062                    available = false;
    1063            }
    1064            if (available)
    1065                ret++;
    1066        }
    1067        return ret;
    1068    }
    1069
    1070    public boolean allowBreakHard() {
    1071        return (getModel() == null ? false : ((TimetableModel)getModel()).isAllowBreakHard());
    1072    }
    1073
    1074    public int getNrRooms() {
    1075        return iNrRooms;
    1076    }
    1077
    1078    public Lecture getParent() {
    1079        return iParent;
    1080    }
    1081
    1082    public void setParent(Lecture parent) {
    1083        iParent = parent;
    1084        iParent.addChild(this);
    1085    }
    1086
    1087    public boolean hasParent() {
    1088        return (iParent != null);
    1089    }
    1090
    1091    public boolean hasChildren(Long subpartId) {
    1092        return (iChildren != null && iChildren.get(subpartId) != null && !iChildren.get(subpartId).isEmpty());
    1093    }
    1094
    1095    public boolean hasAnyChildren() {
    1096        return (iChildren != null && !iChildren.isEmpty());
    1097    }
    1098
    1099    public List<Lecture> getChildren(Long subpartId) {
    1100        return iChildren.get(subpartId);
    1101    }
    1102
    1103    public Set<Long> getChildrenSubpartIds() {
    1104        return (iChildren == null ? null : iChildren.keySet());
    1105    }
    1106
    1107    public Map<Long, List<Lecture>> getChildren() {
    1108        return iChildren;
    1109    }
    1110
    1111    private void addChild(Lecture child) {
    1112        if (iChildren == null)
    1113            iChildren = new HashMap<Long, List<Lecture>>();
    1114        List<Lecture> childrenThisSubpart = iChildren.get(child.getSchedulingSubpartId());
    1115        if (childrenThisSubpart == null) {
    1116            childrenThisSubpart = new ArrayList<Lecture>();
    1117            iChildren.put(child.getSchedulingSubpartId(), childrenThisSubpart);
    1118        }
    1119        childrenThisSubpart.add(child);
    1120    }
    1121
    1122    public boolean isSingleSection() {
    1123        return (iSameSubpartLectures == null || iSameSubpartLectures.size() <= 1);
    1124        /*
    1125        if (iParent == null)
    1126            return (iSameSubpartLectures == null || iSameSubpartLectures.size() <= 1);
    1127        return (iParent.getChildren(getSchedulingSubpartId()).size() <= 1);
    1128        */
    1129    }
    1130
    1131    public java.util.List<Lecture> sameStudentsLectures() {
    1132        return (hasParent() ? getParent().getChildren(getSchedulingSubpartId()) : sameSubpartLectures());
    1133    }
    1134
    1135    public Lecture getChild(Student student, Long subpartId) {
    1136        if (!hasAnyChildren())
    1137            return null;
    1138        List<Lecture> children = getChildren(subpartId);
    1139        if (children == null)
    1140            return null;
    1141        for (Lecture child : children) {
    1142            if (child.students().contains(student))
    1143                return child;
    1144        }
    1145        return null;
    1146    }
    1147
    1148    public int getCommitedConflicts(Placement placement) {
    1149        iLock.readLock().lock();
    1150        try {
    1151            Integer ret = iCommitedConflicts.get(placement);
    1152            if (ret != null) return ret;
    1153        } finally {
    1154            iLock.readLock().unlock();
    1155        }
    1156        iLock.writeLock().lock();
    1157        try {
    1158            int ret = placement.getCommitedConflicts();
    1159            iCommitedConflicts.put(placement, ret);
    1160            return ret;
    1161        } finally {
    1162            iLock.writeLock().unlock();
    1163        }
    1164    }
    1165
    1166    public Set<GroupConstraint> hardGroupSoftConstraints() {
    1167        return iHardGroupSoftConstraints;
    1168    }
    1169
    1170    public Set<GroupConstraint> groupConstraints() {
    1171        return iGroupConstraints;
    1172    }
    1173
    1174    public int minRoomSize() {
    1175        iLock.readLock().lock();
    1176        try {
    1177            if (iCacheMinRoomSize != null) return iCacheMinRoomSize.intValue();
    1178        } finally {
    1179            iLock.readLock().unlock();
    1180        }
    1181        iLock.writeLock().lock();
    1182        try {
    1183            if (iCacheMinRoomSize != null) return iCacheMinRoomSize.intValue();
    1184            if (getNrRooms() <= 1) {
    1185                int min = Integer.MAX_VALUE;
    1186                for (RoomLocation r : roomLocations()) {
    1187                    if (r.getMinPreference() <= Constants.sPreferenceLevelProhibited / 2)
    1188                        min = Math.min(min, r.getRoomSize());
    1189                }
    1190                iCacheMinRoomSize = Integer.valueOf(min);
    1191                return min;
    1192            } else {
    1193                List<RoomLocation> rooms = new ArrayList<RoomLocation>();
    1194                for (RoomLocation r: roomLocations())
    1195                    if (r.getMinPreference() <= Constants.sPreferenceLevelProhibited / 2)
    1196                        rooms.add(r);
    1197                Collections.sort(rooms, new Comparator<RoomLocation>() {
    1198                    @Override
    1199                    public int compare(RoomLocation r1, RoomLocation r2) {
    1200                        if (r1.getRoomSize() < r2.getRoomSize()) return -1;
    1201                        if (r1.getRoomSize() > r2.getRoomSize()) return 1;
    1202                        return r1.compareTo(r2);
    1203                    }
    1204                });
    1205                int min = rooms.isEmpty() ? 0 : rooms.get(Math.min(getNrRooms(), rooms.size()) - 1).getRoomSize();
    1206                iCacheMinRoomSize = Integer.valueOf(min);
    1207                return min;
    1208            }
    1209        } finally {
    1210            iLock.writeLock().unlock();
    1211        }
    1212    }
    1213
    1214    public int maxRoomSize() {
    1215        iLock.readLock().lock();
    1216        try {
    1217            if (iCacheMaxRoomSize != null) return iCacheMaxRoomSize.intValue();
    1218        } finally {
    1219            iLock.readLock().unlock();
    1220        }
    1221        iLock.writeLock().lock();
    1222        try {
    1223            if (iCacheMaxRoomSize != null) return iCacheMaxRoomSize.intValue();
    1224            if (getNrRooms() <= 1) {
    1225                int max = Integer.MIN_VALUE;
    1226                for (RoomLocation r : roomLocations()) {
    1227                    if (r.getMinPreference() <= Constants.sPreferenceLevelProhibited / 2)
    1228                        max = Math.max(max, r.getRoomSize());
    1229                }
    1230                iCacheMaxRoomSize = Integer.valueOf(max);
    1231                return max;
    1232            } else {
    1233                List<RoomLocation> rooms = new ArrayList<RoomLocation>();
    1234                for (RoomLocation r: roomLocations())
    1235                    if (r.getMinPreference() <= Constants.sPreferenceLevelProhibited / 2) rooms.add(r);
    1236                Collections.sort(rooms, new Comparator<RoomLocation>() {
    1237                    @Override
    1238                    public int compare(RoomLocation r1, RoomLocation r2) {
    1239                        if (r1.getRoomSize() > r2.getRoomSize()) return -1;
    1240                        if (r1.getRoomSize() < r2.getRoomSize()) return 1;
    1241                        return r1.compareTo(r2);
    1242                    }
    1243                });
    1244                int max = rooms.isEmpty() ? 0 : rooms.get(Math.min(getNrRooms(), rooms.size()) - 1).getRoomSize();
    1245                iCacheMaxRoomSize = Integer.valueOf(max);
    1246                return max;
    1247            }
    1248        } finally {
    1249            iLock.writeLock().unlock();
    1250        }
    1251    }
    1252
    1253    public boolean canShareRoom() {
    1254        return (!iCanShareRoomGroupConstraints.isEmpty());
    1255    }
    1256
    1257    public boolean canShareRoom(Lecture other) {
    1258        if (other.equals(this))
    1259            return true;
    1260        for (GroupConstraint gc : iCanShareRoomGroupConstraints) {
    1261            if (gc.variables().contains(other))
    1262                return true;
    1263        }
    1264        return false;
    1265    }
    1266
    1267    public Set<GroupConstraint> canShareRoomConstraints() {
    1268        return iCanShareRoomGroupConstraints;
    1269    }
    1270
    1271    public boolean isSingleton() {
    1272        return getNrRooms() == roomLocations().size() && timeLocations().size() == 1;
    1273    }
    1274
    1275    public boolean isValid(Placement placement) {
    1276        TimetableModel model = (TimetableModel) getModel();
    1277        if (model == null)
    1278            return true;
    1279        if (!model.isAllowBreakHard() && !model.getProperties().getPropertyBoolean("General.InteractiveMode", false)) {
    1280            if (getNrRooms() > 1 && isSplitAttendance() && placement.getRoomSize() < minRoomUse()) return false;
    1281            if (placement.isRoomProhibited()) return false;
    1282        }
    1283        if (!checkParents(placement)) return false;
    1284        if (model.hasConstantVariables()) {
    1285            for (Placement confPlacement : model.conflictValuesSkipWeakeningConstraints(model.getEmptyAssignment(), placement)) {
    1286                Lecture lecture = confPlacement.variable();
    1287                if (lecture.isCommitted())
    1288                    return false;
    1289                if (confPlacement.equals(placement))
    1290                    return false;
    1291            }
    1292        } else {
    1293            Set<Placement> conflicts = new HashSet<Placement>();
    1294            for (Constraint<Lecture, Placement> constraint : hardConstraints()) {
    1295                if (constraint instanceof WeakeningConstraint) continue;
    1296                constraint.computeConflicts(model.getEmptyAssignment(), placement, conflicts);
    1297            }
    1298            for (GlobalConstraint<Lecture, Placement> constraint : model.globalConstraints()) {
    1299                if (constraint instanceof WeakeningConstraint) continue;
    1300                constraint.computeConflicts(model.getEmptyAssignment(), placement, conflicts);
    1301            }
    1302            if (conflicts.contains(placement))
    1303                return false;
    1304        }
    1305        return true;
    1306    }
    1307
    1308    public String getNotValidReason(Assignment<Lecture, Placement> assignment, Placement placement, boolean useAmPm) {
    1309        TimetableModel model = (TimetableModel) getModel();
    1310        if (model == null)
    1311            return "no model for class " + getName();
    1312        Map<Constraint<Lecture, Placement>, Set<Placement>> conflictConstraints = model.conflictConstraints(assignment, placement);
    1313        for (Map.Entry<Constraint<Lecture, Placement>, Set<Placement>> entry : conflictConstraints.entrySet()) {
    1314            Constraint<Lecture, Placement> constraint = entry.getKey();
    1315            Set<Placement> conflicts = entry.getValue();
    1316            String cname = constraint.getName();
    1317            if (constraint instanceof RoomConstraint) {
    1318                cname = "Room " + constraint.getName();
    1319            } else if (constraint instanceof InstructorConstraint) {
    1320                cname = "Instructor " + constraint.getName();
    1321            } else if (constraint instanceof GroupConstraint) {
    1322                cname = "Distribution " + constraint.getName();
    1323            } else if (constraint instanceof DepartmentSpreadConstraint) {
    1324                cname = "Balancing of department " + constraint.getName();
    1325            } else if (constraint instanceof SpreadConstraint) {
    1326                cname = "Same subpart spread " + constraint.getName();
    1327            } else if (constraint instanceof ClassLimitConstraint) {
    1328                cname = "Class limit " + constraint.getName();
    1329            }
    1330            for (Placement confPlacement : conflicts) {
    1331                Lecture lecture = confPlacement.variable();
    1332                if (lecture.isCommitted()) {
    1333                    return placement.getLongName(useAmPm) + " conflicts with " + lecture.getName() + " "
    1334                            + confPlacement.getLongName(useAmPm) + " due to constraint " + cname;
    1335                }
    1336                if (confPlacement.equals(placement)) {
    1337                    return placement.getLongName(useAmPm) + " is not valid due to constraint " + cname;
    1338                }
    1339            }
    1340        }
    1341        if (getNrRooms() > 1 && isSplitAttendance() && placement.getRoomSize() < minRoomUse())
    1342            return "selected rooms are too small (" + placement.getRoomSize() + " < " + minRoomUse() + ")";
    1343        if (placement.isMultiRoom() && placement.isRoomProhibited()) {
    1344            int roomIndex = 0;
    1345            for (RoomLocation r : placement.getRoomLocations()) {
    1346                if (Constants.sPreferenceProhibited.equals(Constants.preferenceLevel2preference(r.getPreference(roomIndex))))
    1347                    return "invalid room combination (" + r.getName() + " is prohibited as " + (roomIndex + 1) + ". room)";
    1348                roomIndex++;
    1349            }
    1350        }
    1351        if (placement.isMultiRoom()) {
    1352            for (RoomLocation r1: placement.getRoomLocations())
    1353                for (RoomLocation r2: placement.getRoomLocations())
    1354                    if (r2.getRoomConstraint() != null && r2.getRoomConstraint().getParentRoom() != null && r2.getRoomConstraint().getParentRoom().equals(r1.getRoomConstraint()))
    1355                        return "invalid room combination (" + r2.getName() + " is a partition of " + r1.getName() + ")";
    1356
    1357        }
    1358        return null;
    1359    }
    1360
    1361    @Deprecated
    1362    public String getNotValidReason(Assignment<Lecture, Placement> assignment, Placement placement) {
    1363        return getNotValidReason(assignment, placement, true);
    1364    }
    1365
    1366    public void purgeInvalidValues(boolean interactiveMode) {
    1367        if (isCommitted() || sSaveMemory) return;
    1368        TimetableModel model = (TimetableModel) getModel();
    1369        if (model == null)
    1370            return;
    1371        List<Placement> newValues = new ArrayList<Placement>(values(null).size());
    1372        for (Placement placement : values(null)) {
    1373            if (placement.isValid())
    1374                newValues.add(placement);
    1375        }
    1376        if (!interactiveMode && newValues.size() != values(null).size()) {
    1377            for (Iterator<TimeLocation> i = timeLocations().iterator(); i.hasNext();) {
    1378                TimeLocation timeLocation = i.next();
    1379                boolean hasPlacement = false;
    1380                for (Placement placement : newValues) {
    1381                    if (timeLocation.equals(placement.getTimeLocation())) {
    1382                        hasPlacement = true;
    1383                        break;
    1384                    }
    1385                }
    1386                if (!hasPlacement)
    1387                    i.remove();
    1388            }
    1389            for (Iterator<RoomLocation> i = roomLocations().iterator(); i.hasNext();) {
    1390                RoomLocation roomLocation = i.next();
    1391                boolean hasPlacement = false;
    1392                for (Placement placement : newValues) {
    1393                    if (placement.isMultiRoom()) {
    1394                        if (placement.getRoomLocations().contains(roomLocation)) {
    1395                            hasPlacement = true;
    1396                            break;
    1397                        }
    1398                    } else {
    1399                        if (roomLocation.equals(placement.getRoomLocation())) {
    1400                            hasPlacement = true;
    1401                            break;
    1402                        }
    1403                    }
    1404                }
    1405                if (!hasPlacement)
    1406                    i.remove();
    1407            }
    1408        }
    1409        setValues(newValues);
    1410    }
    1411
    1412    public void setCommitted(boolean committed) {
    1413        iCommitted = committed;
    1414    }
    1415
    1416    public boolean isCommitted() {
    1417        return iCommitted;
    1418    }
    1419
    1420    @Override
    1421    public boolean isConstant() {
    1422        return iCommitted;
    1423    }
    1424
    1425    @Override
    1426    public Placement getConstantValue() {
    1427        return (isCommitted() ? getInitialAssignment() : null);
    1428    }
    1429
    1430    public void setConstantValue(Placement value) {
    1431        setInitialAssignment(value);
    1432    }
    1433
    1434    public int getSpreadPenalty(Assignment<Lecture, Placement> assignment) {
    1435        int spread = 0;
    1436        for (SpreadConstraint sc : getSpreadConstraints()) {
    1437            spread += sc.getPenalty(assignment);
    1438        }
    1439        return spread;
    1440    }
    1441
    1442    @Override
    1443    public int hashCode() {
    1444        return getClassId().hashCode();
    1445    }
    1446
    1447    public Configuration getConfiguration() {
    1448        Lecture lecture = this;
    1449        while (lecture.getParent() != null)
    1450            lecture = lecture.getParent();
    1451        return lecture.iParentConfiguration;
    1452    }
    1453
    1454    public void setConfiguration(Configuration configuration) {
    1455        Lecture lecture = this;
    1456        while (lecture.getParent() != null)
    1457            lecture = lecture.getParent();
    1458        lecture.iParentConfiguration = configuration;
    1459        configuration.addTopLecture(lecture);
    1460    }
    1461
    1462    private int[] iMinMaxRoomPreference = null;
    1463
    1464    public int[] getMinMaxRoomPreference() {
    1465        iLock.readLock().lock();
    1466        try {
    1467            if (iMinMaxRoomPreference != null) return iMinMaxRoomPreference;
    1468        } finally {
    1469            iLock.readLock().unlock();
    1470        }
    1471        iLock.writeLock().lock();
    1472        try {
    1473            if (iMinMaxRoomPreference != null) return iMinMaxRoomPreference;
    1474
    1475            if (getNrRooms() <= 0 || roomLocations().isEmpty()) {
    1476                iMinMaxRoomPreference = new int[] { 0, 0 };
    1477            } else {
    1478                Integer minRoomPref = null, maxRoomPref = null;
    1479                for (RoomLocation r : roomLocations()) {
    1480                    int pref = r.getMinPreference();
    1481                    if (pref >= Constants.sPreferenceLevelRequired / 2 && pref <= Constants.sPreferenceLevelProhibited / 2) {
    1482                        minRoomPref = (minRoomPref == null ? pref : Math.min(minRoomPref, pref));
    1483                        maxRoomPref = (maxRoomPref == null ? pref : Math.max(maxRoomPref, pref));
    1484                    }
    1485                    pref = r.getMaxPreference();
    1486                    if (pref >= Constants.sPreferenceLevelRequired / 2 && pref <= Constants.sPreferenceLevelProhibited / 2) {
    1487                        minRoomPref = (minRoomPref == null ? pref : Math.min(minRoomPref, pref));
    1488                        maxRoomPref = (maxRoomPref == null ? pref : Math.max(maxRoomPref, pref));
    1489                    }
    1490                }
    1491                iMinMaxRoomPreference = new int[] { minRoomPref == null ? 0 : minRoomPref, maxRoomPref == null ? 0 : maxRoomPref };
    1492            }
    1493
    1494            return iMinMaxRoomPreference;
    1495        } finally {
    1496            iLock.writeLock().unlock();
    1497        }
    1498    }
    1499
    1500    private double[] iMinMaxTimePreference = null;
    1501
    1502    public double[] getMinMaxTimePreference() {
    1503        iLock.readLock().lock();
    1504        try {
    1505            if (iMinMaxTimePreference != null) return iMinMaxTimePreference;
    1506        } finally {
    1507            iLock.readLock().unlock();
    1508        }
    1509        iLock.writeLock().lock();
    1510        try {
    1511            if (iMinMaxTimePreference != null) return iMinMaxTimePreference;
    1512
    1513            Double minTimePref = null, maxTimePref = null;
    1514            for (TimeLocation t : timeLocations()) {
    1515                double npref = t.getNormalizedPreference();
    1516                int pref = t.getPreference();
    1517                if (pref >= Constants.sPreferenceLevelRequired / 2 && pref <= Constants.sPreferenceLevelProhibited / 2) {
    1518                    minTimePref = (minTimePref == null ? npref : Math.min(minTimePref, npref));
    1519                    maxTimePref = (maxTimePref == null ? npref : Math.max(maxTimePref, npref));
    1520                }
    1521            }
    1522            iMinMaxTimePreference = new double[] { minTimePref == null ? 0.0 : minTimePref, maxTimePref == null ? 0.0 : maxTimePref };
    1523
    1524            return iMinMaxTimePreference;
    1525        } finally {
    1526            iLock.writeLock().unlock();
    1527        }
    1528    }
    1529
    1530    public void setOrd(int ord) {
    1531        iOrd = ord;
    1532    }
    1533
    1534    public int getOrd() {
    1535        return iOrd;
    1536    }
    1537
    1538    @Override
    1539    public int compareTo(Lecture o) {
    1540        int cmp = Double.compare(getOrd(), o.getOrd());
    1541        if (cmp != 0)
    1542            return cmp;
    1543        return super.compareTo(o);
    1544    }
    1545
    1546    public String getNote() {
    1547        return iNote;
    1548    }
    1549
    1550    public void setNote(String note) {
    1551        iNote = note;
    1552    }
    1553
    1554    public boolean areStudentConflictsHard(Lecture other) {
    1555        return StudentConflict.hard(this, other);
    1556    }
    1557
    1558    public void clearIgnoreStudentConflictsWithCache() {
    1559        iIgnoreStudentConflictsWith.set(null);
    1560    }
    1561
    1562    /**
    1563     * Returns true if there is {@link IgnoreStudentConflictsConstraint} between the two lectures.
    1564     * @param other another class
    1565     * @return true if student conflicts between this and the given calls are to be ignored
    1566     */
    1567   public boolean isToIgnoreStudentConflictsWith(Lecture other) {
    1568       Set<Long> cache = iIgnoreStudentConflictsWith.get();
    1569       if (cache != null)
    1570           return cache.contains(other.getClassId());
    1571       cache = new HashSet<Long>();
    1572       for (Constraint<Lecture, Placement> constraint: constraints()) {
    1573           if (constraint instanceof IgnoreStudentConflictsConstraint)
    1574               for (Lecture x: constraint.variables()) {
    1575                   if (!x.equals(this)) cache.add(x.getClassId());
    1576               }
    1577           if (constraint instanceof GroupConstraint && ((GroupConstraint)constraint).getType().is(GroupConstraint.Flag.IGNORE_STUDENTS))
    1578               for (Lecture x: constraint.variables()) {
    1579                   if (!x.equals(this)) cache.add(x.getClassId());
    1580               }
    1581       }
    1582       iIgnoreStudentConflictsWith.set(cache);
    1583       return cache.contains(other.getClassId());
    1584    }
    1585
    1586   /**
    1587    * Get class weight. This weight is used with the criteria. E.g., class that is not meeting all the
    1588    * semester can have a lower weight. Defaults to 1.0
    1589    * @return class weight
    1590    */
    1591   public double getWeight() { return iWeight; }
    1592   /**
    1593    * Set class weight. This weight is used with the criteria. E.g., class that is not meeting all the
    1594    * semester can have a lower weight.
    1595    * @param weight class weight
    1596    */
    1597   public void setWeight(double weight) { iWeight = weight; }
    1598
    1599   @Override
    1600   public LectureContext createAssignmentContext(Assignment<Lecture, Placement> assignment) {
    1601       return new LectureContext();
    1602   }
    1603
    1604   public class LectureContext implements AssignmentContext {
    1605       private Set<JenrlConstraint> iActiveJenrls = new HashSet<JenrlConstraint>();
    1606
    1607       /**
    1608        * Add active jenrl constraint (active mean that there is at least one
    1609        * student between its classes)
    1610        * @param constr active join enrollment constraint
    1611        */
    1612       public void addActiveJenrl(JenrlConstraint constr) {
    1613           iActiveJenrls.add(constr);
    1614       }
    1615
    1616       /**
    1617        * Active jenrl constraints (active mean that there is at least one student
    1618        * between its classes)
    1619        * @return set of active join enrollment constraints
    1620        */
    1621       public Set<JenrlConstraint> activeJenrls() {
    1622           return iActiveJenrls;
    1623       }
    1624
    1625       /**
    1626        * Remove active jenrl constraint (active mean that there is at least one
    1627        * student between its classes)
    1628        * @param constr active join enrollment constraint
    1629        */
    1630       public void removeActiveJenrl(JenrlConstraint constr) {
    1631           iActiveJenrls.remove(constr);
    1632       }
    1633   }
    1634
    1635   public int getMaxRoomCombinations() {
    1636       return iMaxRoomCombinations;
    1637   }
    1638
    1639   public void setMaxRoomCombinations(int maxRoomCombinations) {
    1640       iMaxRoomCombinations = maxRoomCombinations;
    1641   }
    1642
    1643   private Integer iMinWeeks = null;
    1644   public int getMinWeeks() {
    1645       if (iMinWeeks == null) {
    1646           iMinWeeks = 0;
    1647           for (TimeLocation t: timeLocations()) {
    1648               int s = t.getWeekCode().nextSetBit(0);
    1649               int e = t.getWeekCode().previousSetBit(t.getWeekCode().size());
    1650               int weeks = 1 + (e - s) / 7;
    1651               if (iMinWeeks == 0 || weeks < iMinWeeks) iMinWeeks = weeks;
    1652           }
    1653       }
    1654       return iMinWeeks;
    1655   }
    1656
    1657   /**
    1658    * When using multiple rooms, split attendance means that the class is split among the given rooms.
    1659    * @return true means class is split among rooms, false means each room must be big enough for the class
    1660    */
    1661   public boolean isSplitAttendance() { return iSplitAttendance; }
    1662
    1663   /**
    1664    * When using multiple rooms, split attendance means that the class is split among the given rooms.
    1665    * @param splitAttendance true means class is split among rooms, false means each room must be big enough for the class
    1666    */
    1667   public void setSplitAttendance(boolean splitAttendance) { iSplitAttendance = splitAttendance; }
    1668
    1669   /**
    1670    * Check if the assigned rooms are too small for a class with multiple rooms and split attendace.
    1671    */
    1672   private boolean isTooSmall(Collection<RoomLocation> rooms) {
    1673       if (getNrRooms() <= 1 && !isSplitAttendance()) return false;
    1674       int size = 0;
    1675       for (RoomLocation room: rooms)
    1676           size += room.getRoomSize();
    1677       return size < minRoomSize();
    1678   }
    1679
    1680   /**
    1681    * Check if the assigned rooms are too small for a class with multiple rooms and split attendace.
    1682    */
    1683   private boolean isTooSmall(Placement p) {
    1684       return getNrRooms() > 1 && isSplitAttendance() && p.getRoomSize() < minRoomUse();
    1685   }
    1686
    1687   /**
    1688    * Check that the room and its parent are not used at the same time
    1689    */
    1690   private boolean checkParents(Placement p) {
    1691       if (p.isMultiRoom()) {
    1692           for (RoomLocation r1: p.getRoomLocations())
    1693               for (RoomLocation r2: p.getRoomLocations())
    1694                   if (r2.getRoomConstraint() != null && r2.getRoomConstraint().getParentRoom() != null && r2.getRoomConstraint().getParentRoom().equals(r1.getRoomConstraint()))
    1695                       return false;
    1696       }
    1697       return true;
    1698   }
    1699}