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