001package org.cpsolver.studentsct.model;
002
003import java.text.DecimalFormat;
004import java.util.ArrayList;
005import java.util.Collection;
006import java.util.Collections;
007import java.util.HashMap;
008import java.util.HashSet;
009import java.util.List;
010import java.util.Map;
011import java.util.Set;
012import java.util.TreeSet;
013
014import org.cpsolver.coursett.model.TimeLocation;
015import org.cpsolver.ifs.assignment.Assignment;
016import org.cpsolver.ifs.assignment.AssignmentComparator;
017import org.cpsolver.ifs.util.ToolBox;
018import org.cpsolver.studentsct.StudentSectioningModel;
019import org.cpsolver.studentsct.constraint.ConfigLimit;
020import org.cpsolver.studentsct.constraint.CourseLimit;
021import org.cpsolver.studentsct.constraint.LinkedSections;
022import org.cpsolver.studentsct.constraint.SectionLimit;
023import org.cpsolver.studentsct.reservation.Reservation;
024
025
026/**
027 * Representation of a request of a student for one or more course. A student
028 * requests one of the given courses, preferably the first one. <br>
029 * <br>
030 * 
031 * @version StudentSct 1.3 (Student Sectioning)<br>
032 *          Copyright (C) 2007 - 2014 Tomas Muller<br>
033 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
034 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
035 * <br>
036 *          This library is free software; you can redistribute it and/or modify
037 *          it under the terms of the GNU Lesser General Public License as
038 *          published by the Free Software Foundation; either version 3 of the
039 *          License, or (at your option) any later version. <br>
040 * <br>
041 *          This library is distributed in the hope that it will be useful, but
042 *          WITHOUT ANY WARRANTY; without even the implied warranty of
043 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
044 *          Lesser General Public License for more details. <br>
045 * <br>
046 *          You should have received a copy of the GNU Lesser General Public
047 *          License along with this library; if not see
048 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
049 */
050public class CourseRequest extends Request {
051    private static DecimalFormat sDF = new DecimalFormat("0.000");
052    private List<Course> iCourses = null;
053    private Set<Choice> iWaitlistedChoices = new HashSet<Choice>();
054    private Set<Choice> iSelectedChoices = new HashSet<Choice>();
055    private boolean iWaitlist = false;
056    private Long iTimeStamp = null;
057    private Double iCachedMinPenalty = null, iCachedMaxPenalty = null;
058    public static boolean sSameTimePrecise = false;
059    private Set<RequestGroup> iRequestGroups = new HashSet<RequestGroup>();
060
061    /**
062     * Constructor
063     * 
064     * @param id
065     *            request unique id
066     * @param priority
067     *            request priority
068     * @param alternative
069     *            true if the request is alternative (alternative request can be
070     *            assigned instead of a non-alternative course requests, if it
071     *            is left unassigned)
072     * @param student
073     *            appropriate student
074     * @param courses
075     *            list of requested courses (in the correct order -- first is
076     *            the requested course, second is the first alternative, etc.)
077     * @param waitlist
078     *            time stamp of the request if the student can be put on a wait-list (no alternative
079     *            course request will be given instead)
080     * @param timeStamp request time stamp
081     */
082    public CourseRequest(long id, int priority, boolean alternative, Student student, java.util.List<Course> courses,
083            boolean waitlist, Long timeStamp) {
084        super(id, priority, alternative, student);
085        iCourses = new ArrayList<Course>(courses);
086        for (Course course: iCourses)
087            course.getRequests().add(this);
088        iWaitlist = waitlist;
089        iTimeStamp = timeStamp;
090    }
091
092    /**
093     * List of requested courses (in the correct order -- first is the requested
094     * course, second is the first alternative, etc.)
095     * @return requested course offerings
096     */
097    public List<Course> getCourses() {
098        return iCourses;
099    }
100
101    /**
102     * Create enrollment for the given list of sections. The list of sections
103     * needs to be correct, i.e., a section for each subpart of a configuration
104     * of one of the requested courses.
105     * @param sections selected sections
106     * @param reservation selected reservation
107     * @return enrollment
108     */
109    public Enrollment createEnrollment(Set<? extends SctAssignment> sections, Reservation reservation) {
110        if (sections == null || sections.isEmpty())
111            return null;
112        Config config = ((Section) sections.iterator().next()).getSubpart().getConfig();
113        Course course = null;
114        for (Course c: iCourses) {
115            if (c.getOffering().getConfigs().contains(config)) {
116                course = c;
117                break;
118            }
119        }
120        return new Enrollment(this, iCourses.indexOf(course), course, config, sections, reservation);
121    }
122
123    /**
124     * Create enrollment for the given list of sections. The list of sections
125     * needs to be correct, i.e., a section for each subpart of a configuration
126     * of one of the requested courses.
127     * @param assignment current assignment (to guess the reservation)
128     * @param sections selected sections
129     * @return enrollment
130     */
131    public Enrollment createEnrollment(Assignment<Request, Enrollment> assignment, Set<? extends SctAssignment> sections) {
132        Enrollment ret = createEnrollment(sections, null);
133        ret.guessReservation(assignment, true);
134        return ret;
135        
136    }
137    
138    /**
139     * Maximal domain size (i.e., number of enrollments of a course request), -1 if there is no limit.
140     * @return maximal domain size, -1 if unlimited
141     */
142    protected int getMaxDomainSize() {
143        StudentSectioningModel model = (StudentSectioningModel) getModel();
144        return model == null ? -1 : model.getMaxDomainSize();
145    }
146
147    /**
148     * Return all possible enrollments.
149     */
150    @Override
151    public List<Enrollment> computeEnrollments(Assignment<Request, Enrollment> assignment) {
152        List<Enrollment> ret = new ArrayList<Enrollment>();
153        int idx = 0;
154        for (Course course : iCourses) {
155            for (Config config : course.getOffering().getConfigs()) {
156                computeEnrollments(assignment, ret, idx, 0, course, config, new HashSet<Section>(), 0, false, false,
157                        false, false, getMaxDomainSize() <= 0 ? -1 : ret.size() + getMaxDomainSize());
158            }
159            idx++;
160        }
161        return ret;
162    }
163
164    /**
165     * Return a subset of all enrollments -- randomly select only up to
166     * limitEachConfig enrollments of each config.
167     * @param assignment current assignment
168     * @param limitEachConfig maximal number of enrollments in each configuration
169     * @return computed enrollments
170     */
171    public List<Enrollment> computeRandomEnrollments(Assignment<Request, Enrollment> assignment, int limitEachConfig) {
172        List<Enrollment> ret = new ArrayList<Enrollment>();
173        int idx = 0;
174        for (Course course : iCourses) {
175            for (Config config : course.getOffering().getConfigs()) {
176                computeEnrollments(assignment, ret, idx, 0, course, config, new HashSet<Section>(), 0, false, false,
177                        false, true, (limitEachConfig <= 0 ? limitEachConfig : ret.size() + limitEachConfig));
178            }
179            idx++;
180        }
181        return ret;
182    }
183
184    /**
185     * Return true if the both sets of sections contain sections of the same
186     * subparts, and each pair of sections of the same subpart is offered at the
187     * same time.
188     */
189    private boolean sameTimes(Set<Section> sections1, Set<Section> sections2) {
190        for (Section s1 : sections1) {
191            Section s2 = null;
192            for (Section s : sections2) {
193                if (s.getSubpart().equals(s1.getSubpart())) {
194                    s2 = s;
195                    break;
196                }
197            }
198            if (s2 == null)
199                return false;
200            if (!ToolBox.equals(s1.getTime(), s2.getTime()))
201                return false;
202        }
203        return true;
204    }
205
206    /**
207     * Recursive computation of enrollments
208     * 
209     * @param enrollments
210     *            list of enrollments to be returned
211     * @param priority
212     *            zero for the course, one for the first alternative, two for the second alternative
213     * @param penalty
214     *            penalty of the selected sections
215     * @param course
216     *            selected course
217     * @param config
218     *            selected configuration
219     * @param sections
220     *            sections selected so far
221     * @param idx
222     *            index of the subparts (a section of 0..idx-1 subparts has been
223     *            already selected)
224     * @param availableOnly
225     *            only use available sections
226     * @param skipSameTime
227     *            for each possible times, pick only one section
228     * @param selectedOnly
229     *            select only sections that are selected (
230     *            {@link CourseRequest#isSelected(Section)} is true)
231     * @param random
232     *            pick sections in a random order (useful when limit is used)
233     * @param limit
234     *            when above zero, limit the number of selected enrollments to
235     *            this limit
236     * @param reservations
237     *            list of applicable reservations
238     */
239    private void computeEnrollments(Assignment<Request, Enrollment> assignment, Collection<Enrollment> enrollments, int priority, double penalty, Course course, Config config,
240            HashSet<Section> sections, int idx, boolean availableOnly, boolean skipSameTime, boolean selectedOnly,
241            boolean random, int limit) {
242        if (limit > 0 && enrollments.size() >= limit)
243            return;
244        if (idx == 0) { // run only once for each configuration
245            boolean canOverLimit = false;
246            if (availableOnly) {
247                for (Reservation r: getReservations(course)) {
248                    if (!r.canBatchAssignOverLimit()) continue;
249                    if (!r.getConfigs().isEmpty() && !r.getConfigs().contains(config)) continue;
250                    if (r.getReservedAvailableSpace(assignment, this) < getWeight()) continue;
251                    canOverLimit = true; break;
252                }
253            }
254            if (!canOverLimit) {
255                if (availableOnly && config.getLimit() >= 0 && ConfigLimit.getEnrollmentWeight(assignment, config, this) > config.getLimit())
256                    return;
257                if (availableOnly && course.getLimit() >= 0 && CourseLimit.getEnrollmentWeight(assignment, course, this) > course.getLimit())
258                    return;
259                if (config.getOffering().hasReservations()) {
260                    boolean hasReservation = false, hasConfigReservation = false, reservationMustBeUsed = false;
261                    for (Reservation r: getReservations(course)) {
262                        if (r.mustBeUsed()) reservationMustBeUsed = true;
263                        if (availableOnly && r.getReservedAvailableSpace(assignment, this) < getWeight()) continue;
264                        if (r.getConfigs().isEmpty()) {
265                            hasReservation = true;
266                        } else if (r.getConfigs().contains(config)) {
267                            hasReservation = true;
268                            hasConfigReservation = true;
269                        }
270                    }
271                    if (!hasConfigReservation && config.getTotalUnreservedSpace() < getWeight())
272                        return;
273                    if (!hasReservation && config.getOffering().getTotalUnreservedSpace() < getWeight())
274                        return;
275                    if (availableOnly && !hasReservation && config.getOffering().getUnreservedSpace(assignment, this) < getWeight())
276                        return;
277                    if (availableOnly && !hasConfigReservation && config.getUnreservedSpace(assignment, this) < getWeight())
278                        return;
279                    if (!hasReservation && reservationMustBeUsed)
280                        return;
281                }
282            }
283        }
284        if (config.getSubparts().size() == idx) {
285            if (skipSameTime && sSameTimePrecise) {
286                boolean waitListedOrSelected = false;
287                if (!getSelectedChoices().isEmpty() || !getWaitlistedChoices().isEmpty()) {
288                    for (Section section : sections) {
289                        if (isWaitlisted(section) || isSelected(section)) {
290                            waitListedOrSelected = true;
291                            break;
292                        }
293                    }
294                }
295                if (!waitListedOrSelected) {
296                    for (Enrollment enrollment : enrollments) {
297                        if (sameTimes(enrollment.getSections(), sections))
298                            return;
299                    }
300                }
301            }
302            if (!config.getOffering().hasReservations()) {
303                enrollments.add(new Enrollment(this, priority, null, config, new HashSet<SctAssignment>(sections), null));
304            } else {
305                Enrollment e = new Enrollment(this, priority, null, config, new HashSet<SctAssignment>(sections), null);
306                boolean mustHaveReservation = config.getOffering().getTotalUnreservedSpace() < getWeight();
307                boolean mustHaveConfigReservation = config.getTotalUnreservedSpace() < getWeight();
308                boolean mustHaveSectionReservation = false;
309                for (Section s: sections) {
310                    if (s.getTotalUnreservedSpace() < getWeight()) {
311                        mustHaveSectionReservation = true;
312                        break;
313                    }
314                }
315                boolean canOverLimit = false;
316                if (availableOnly) {
317                    for (Reservation r: getReservations(course)) {
318                        if (!r.canBatchAssignOverLimit() || !r.isIncluded(e)) continue;
319                        if (r.getReservedAvailableSpace(assignment, this) < getWeight()) continue;
320                        enrollments.add(new Enrollment(this, priority, null, config, new HashSet<SctAssignment>(sections), r));
321                        canOverLimit = true;
322                    }
323                }
324                if (!canOverLimit) {
325                    boolean reservationMustBeUsed = false;
326                    reservations: for (Reservation r: (availableOnly ? getSortedReservations(assignment, course) : getReservations(course))) {
327                        if (r.mustBeUsed()) reservationMustBeUsed = true;
328                        if (!r.isIncluded(e)) continue;
329                        if (availableOnly && r.getReservedAvailableSpace(assignment, this) < getWeight()) continue;
330                        if (mustHaveConfigReservation && r.getConfigs().isEmpty()) continue;
331                        if (mustHaveSectionReservation)
332                            for (Section s: sections)
333                                if (r.getSections(s.getSubpart()) == null && s.getTotalUnreservedSpace() < getWeight()) continue reservations;
334                        enrollments.add(new Enrollment(this, priority, null, config, new HashSet<SctAssignment>(sections), r));
335                        if (availableOnly) return; // only one available reservation suffice (the best matching one)
336                    }
337                    // a case w/o reservation
338                    if (!(mustHaveReservation || mustHaveConfigReservation || mustHaveSectionReservation) &&
339                        !(availableOnly && config.getOffering().getUnreservedSpace(assignment, this) < getWeight()) &&
340                        !reservationMustBeUsed) {
341                        enrollments.add(new Enrollment(this, (getReservations(course).isEmpty() ? 0 : 1) + priority, null, config, new HashSet<SctAssignment>(sections), null));
342                    }
343                }
344            }
345        } else {
346            Subpart subpart = config.getSubparts().get(idx);
347            HashSet<TimeLocation> times = (skipSameTime ? new HashSet<TimeLocation>() : null);
348            List<Section> sectionsThisSubpart = subpart.getSections();
349            if (skipSameTime) {
350                sectionsThisSubpart = new ArrayList<Section>(subpart.getSections());
351                Collections.sort(sectionsThisSubpart, new AssignmentComparator<Section, Request, Enrollment>(assignment));
352            }
353            List<Section> matchingSectionsThisSubpart = new ArrayList<Section>(subpart.getSections().size());
354            boolean hasChildren = !subpart.getChildren().isEmpty();
355            for (Section section : sectionsThisSubpart) {
356                if (section.isCancelled())
357                    continue;
358                if (getInitialAssignment() != null && (getModel() != null && ((StudentSectioningModel)getModel()).getKeepInitialAssignments()) &&
359                        !getInitialAssignment().getAssignments().contains(section))
360                    continue;
361                if (section.getParent() != null && !sections.contains(section.getParent()))
362                    continue;
363                if (section.isOverlapping(sections))
364                    continue;
365                if (selectedOnly && !isSelected(section))
366                    continue;
367                boolean canOverLimit = false;
368                if (availableOnly) {
369                    for (Reservation r: getReservations(course)) {
370                        if (!r.canBatchAssignOverLimit()) continue;
371                        if (r.getSections(subpart) != null && !r.getSections(subpart).contains(section)) continue;
372                        if (r.getReservedAvailableSpace(assignment, this) < getWeight()) continue;
373                        canOverLimit = true; break;
374                    }
375                }
376                if (!canOverLimit) {
377                    if (availableOnly && section.getLimit() >= 0
378                            && SectionLimit.getEnrollmentWeight(assignment, section, this) > section.getLimit())
379                        continue;
380                    if (config.getOffering().hasReservations()) {
381                        boolean hasReservation = false, hasSectionReservation = false, reservationMustBeUsed = false;
382                        for (Reservation r: getReservations(course)) {
383                            if (r.mustBeUsed()) reservationMustBeUsed = true;
384                            if (availableOnly && r.getReservedAvailableSpace(assignment, this) < getWeight()) continue;
385                            if (r.getSections(subpart) == null) {
386                                hasReservation = true;
387                            } else if (r.getSections(subpart).contains(section)) {
388                                hasReservation = true;
389                                hasSectionReservation = true;
390                            }
391                        }
392                        if (!hasSectionReservation && section.getTotalUnreservedSpace() < getWeight())
393                            continue;
394                        if (availableOnly && !hasSectionReservation && section.getUnreservedSpace(assignment, this) < getWeight())
395                            continue;
396                        if (!hasReservation && reservationMustBeUsed)
397                            continue;
398                    }
399                }
400                if (skipSameTime && section.getTime() != null && !hasChildren && !times.add(section.getTime()) && !isSelected(section) && !isWaitlisted(section) && 
401                        (section.getIgnoreConflictWithSectionIds() == null || section.getIgnoreConflictWithSectionIds().isEmpty()))
402                    continue;
403                matchingSectionsThisSubpart.add(section);
404            }
405            if (random || limit > 0) {
406                sectionsThisSubpart = new ArrayList<Section>(sectionsThisSubpart);
407                Collections.shuffle(sectionsThisSubpart);
408            }
409            int i = 0;
410            for (Section section: matchingSectionsThisSubpart) {
411                sections.add(section);
412                computeEnrollments(assignment, enrollments, priority, penalty + section.getPenalty(), course, config, sections, idx + 1,
413                        availableOnly, skipSameTime, selectedOnly, random,
414                        limit < 0 ? limit : Math.max(1, limit * (1 + i) / matchingSectionsThisSubpart.size())
415                        );
416                sections.remove(section);
417                i++;
418            }
419        }
420    }
421
422    /** Return all enrollments that are available 
423     * @param assignment current assignment
424     * @return all available enrollments
425     **/
426    public List<Enrollment> getAvaiableEnrollments(Assignment<Request, Enrollment> assignment) {
427        List<Enrollment> ret = new ArrayList<Enrollment>();
428        int idx = 0;
429        for (Course course : iCourses) {
430            for (Config config : course.getOffering().getConfigs()) {
431                computeEnrollments(assignment, ret, idx, 0, course, config, new HashSet<Section>(), 0, true, false, false, false,
432                        getMaxDomainSize() <= 0 ? -1 : ret.size() + getMaxDomainSize());
433            }
434            idx++;
435        }
436        return ret;
437    }
438
439    /**
440     * Return all enrollments that are selected (
441     * {@link CourseRequest#isSelected(Section)} is true)
442     * 
443     * @param assignment current assignment
444     * @param availableOnly
445     *            pick only available sections
446     * @return selected enrollments
447     */
448    public List<Enrollment> getSelectedEnrollments(Assignment<Request, Enrollment> assignment, boolean availableOnly) {
449        if (getSelectedChoices().isEmpty())
450            return null;
451        Choice firstChoice = getSelectedChoices().iterator().next();
452        List<Enrollment> enrollments = new ArrayList<Enrollment>();
453        for (Course course : iCourses) {
454            if (!course.getOffering().equals(firstChoice.getOffering()))
455                continue;
456            for (Config config : course.getOffering().getConfigs()) {
457                computeEnrollments(assignment, enrollments, 0, 0, course, config, new HashSet<Section>(), 0, availableOnly, false, true, false, -1);
458            }
459        }
460        return enrollments;
461    }
462
463    /**
464     * Return all enrollments that are available, pick only the first section of
465     * the sections with the same time (of each subpart, {@link Section}
466     * comparator is used)
467     * @param assignment current assignment
468     * @return available enrollments 
469     */
470    public List<Enrollment> getAvaiableEnrollmentsSkipSameTime(Assignment<Request, Enrollment> assignment) {
471        List<Enrollment> ret = new ArrayList<Enrollment>();
472        if (getInitialAssignment() != null)
473            ret.add(getInitialAssignment());
474        int idx = 0;
475        for (Course course : iCourses) {
476            boolean skipSameTime = true;
477            for (LinkedSections link: getStudent().getLinkedSections())
478                if (link.getOfferings().contains(course.getOffering())) { skipSameTime = false; break; }
479            for (Config config : course.getOffering().getConfigs()) {
480                computeEnrollments(assignment, ret, idx, 0, course, config, new HashSet<Section>(), 0, true, skipSameTime, false, false,
481                        getMaxDomainSize() <= 0 ? -1 : ret.size() + getMaxDomainSize());
482            }
483            idx++;
484        }
485        return ret;
486    }
487
488    /**
489     * Return all possible enrollments, but pick only the first section of
490     * the sections with the same time (of each subpart, {@link Section}
491     * comparator is used).
492     * @param assignment current assignment
493     * @return computed enrollments 
494     */
495    public List<Enrollment> getEnrollmentsSkipSameTime(Assignment<Request, Enrollment> assignment) {
496        List<Enrollment> ret = new ArrayList<Enrollment>();
497        int idx = 0;
498        for (Course course : iCourses) {
499            for (Config config : course.getOffering().getConfigs()) {
500                boolean skipSameTime = true;
501                for (LinkedSections link: getStudent().getLinkedSections())
502                    if (link.getOfferings().contains(course.getOffering())) { skipSameTime = false; break; }
503                computeEnrollments(assignment, ret, idx, 0, course, config, new HashSet<Section>(), 0, false, skipSameTime, false, false,
504                        getMaxDomainSize() <= 0 ? -1 : ret.size() + getMaxDomainSize());
505            }
506            idx++;
507        }
508        return ret;
509    }
510
511    /** Wait-listed choices 
512     * @return wait-listed choices
513     **/
514    public Set<Choice> getWaitlistedChoices() {
515        return iWaitlistedChoices;
516    }
517
518    /**
519     * Return true when the given section is wait-listed (i.e., its choice is
520     * among wait-listed choices)
521     * @param section given section
522     * @return true if the given section matches the wait-listed choices
523     */
524    public boolean isWaitlisted(Section section) {
525        for (Choice choice: iWaitlistedChoices)
526            if (choice.sameChoice(section)) return true;
527        return false;
528    }
529
530    /** Selected choices 
531     * @return selected choices
532     **/
533    public Set<Choice> getSelectedChoices() {
534        return iSelectedChoices;
535    }
536
537    /**
538     * Return true when the given section is selected (i.e., its choice is among
539     * selected choices)
540     * @param section given section
541     * @return true if the given section matches the selected choices
542     */
543    public boolean isSelected(Section section) {
544        boolean hasMatch = false;
545        for (Choice choice: iSelectedChoices) {
546            if (choice.sameChoice(section) || choice.sameConfiguration(section)) return true;
547            if (choice.isMatching(section)) hasMatch = true;
548        }
549        return !iSelectedChoices.isEmpty() && !hasMatch;
550    }
551
552    /**
553     * Request name: A for alternative, 1 + priority, (w) when wait-list, list of
554     * course names
555     */
556    @Override
557    public String getName() {
558        String ret = (isAlternative() ? "A" : "")
559                + (1 + getPriority() + (isAlternative() ? -getStudent().nrRequests() : 0)) + ". "
560                + (isWaitlist() ? "(w) " : "");
561        int idx = 0;
562        for (Course course : iCourses) {
563            if (idx == 0)
564                ret += course.getName();
565            else
566                ret += ", " + idx + ". alt " + course.getName();
567            idx++;
568        }
569        return ret;
570    }
571
572    /**
573     * True if the student can be put on a wait-list (no alternative course
574     * request will be given instead)
575     * @return true if the request can be wait-listed
576     */
577    public boolean isWaitlist() {
578        return iWaitlist;
579    }
580    
581    /**
582     * True if the student can be put on a wait-list (no alternative course
583     * request will be given instead)
584     * @param waitlist true if the request can be wait-listed
585     */
586    public void setWaitlist(boolean waitlist) {
587        iWaitlist = waitlist;
588    }
589    
590    /**
591     * Time stamp of the request
592     * @return request time stamp
593     */
594    public Long getTimeStamp() {
595        return iTimeStamp;
596    }
597
598    @Override
599    public String toString() {
600        return getName() + (getWeight() != 1.0 ? " (W:" + sDF.format(getWeight()) + ")" : "");
601    }
602
603    /** Return course of the requested courses with the given id 
604     * @param courseId course offering id
605     * @return course of the given id
606     **/
607    public Course getCourse(long courseId) {
608        for (Course course : iCourses) {
609            if (course.getId() == courseId)
610                return course;
611        }
612        return null;
613    }
614
615    /** Return configuration of the requested courses with the given id 
616     * @param configId instructional offering configuration unique id
617     * @return config of the given id
618     **/
619    public Config getConfig(long configId) {
620        for (Course course : iCourses) {
621            for (Config config : course.getOffering().getConfigs()) {
622                if (config.getId() == configId)
623                    return config;
624            }
625        }
626        return null;
627    }
628
629    /** Return subpart of the requested courses with the given id 
630     * @param subpartId scheduling subpart unique id
631     * @return subpart of the given id
632     **/
633    public Subpart getSubpart(long subpartId) {
634        for (Course course : iCourses) {
635            for (Config config : course.getOffering().getConfigs()) {
636                for (Subpart subpart : config.getSubparts()) {
637                    if (subpart.getId() == subpartId)
638                        return subpart;
639                }
640            }
641        }
642        return null;
643    }
644
645    /** Return section of the requested courses with the given id 
646     * @param sectionId class unique id
647     * @return section of the given id
648     **/
649    public Section getSection(long sectionId) {
650        for (Course course : iCourses) {
651            for (Config config : course.getOffering().getConfigs()) {
652                for (Subpart subpart : config.getSubparts()) {
653                    for (Section section : subpart.getSections()) {
654                        if (section.getId() == sectionId)
655                            return section;
656                    }
657                }
658            }
659        }
660        return null;
661    }
662
663    /**
664     * Minimal penalty (minimum of {@link Offering#getMinPenalty()} among
665     * requested courses)
666     * @return minimal penalty
667     */
668    public double getMinPenalty() {
669        if (iCachedMinPenalty == null) {
670            double min = Double.MAX_VALUE;
671            for (Course course : iCourses) {
672                min = Math.min(min, course.getOffering().getMinPenalty());
673            }
674            iCachedMinPenalty = new Double(min);
675        }
676        return iCachedMinPenalty.doubleValue();
677    }
678
679    /**
680     * Maximal penalty (maximum of {@link Offering#getMaxPenalty()} among
681     * requested courses)
682     * @return maximal penalty
683     */
684    public double getMaxPenalty() {
685        if (iCachedMaxPenalty == null) {
686            double max = Double.MIN_VALUE;
687            for (Course course : iCourses) {
688                max = Math.max(max, course.getOffering().getMaxPenalty());
689            }
690            iCachedMaxPenalty = new Double(max);
691        }
692        return iCachedMaxPenalty.doubleValue();
693    }
694
695    /** Clear cached min/max penalties and cached bound */
696    public void clearCache() {
697        iCachedMaxPenalty = null;
698        iCachedMinPenalty = null;
699    }
700
701    /**
702     * Estimated bound for this request -- it estimates the smallest value among
703     * all possible enrollments
704     */
705    @Override
706    public double getBound() {
707        return - getWeight() * ((StudentSectioningModel)getModel()).getStudentWeights().getBound(this);
708        /*
709        if (iCachedBound == null) {
710            iCachedBound = new Double(-Math.pow(Enrollment.sPriorityWeight, getPriority())
711                    * (isAlternative() ? Enrollment.sAlterativeWeight : 1.0)
712                    * Math.pow(Enrollment.sInitialWeight, (getInitialAssignment() == null ? 0 : 1))
713                    * Math.pow(Enrollment.sSelectedWeight, (iSelectedChoices.isEmpty() ? 0 : 1))
714                    * Math.pow(Enrollment.sWaitlistedWeight, (iWaitlistedChoices.isEmpty() ? 0 : 1))
715                    *
716                    // Math.max(Enrollment.sMinWeight,getWeight()) *
717                    (getStudent().isDummy() ? Student.sDummyStudentWeight : 1.0)
718                    * Enrollment.normalizePenalty(getMinPenalty()));
719        }
720        return iCachedBound.doubleValue();
721        */
722    }
723
724    /** Return true if request is assigned. */
725    @Override
726    public boolean isAssigned(Assignment<Request, Enrollment> assignment) {
727        Enrollment e = assignment.getValue(this);
728        return e != null && !e.getAssignments().isEmpty();
729    }
730
731    @Override
732    public boolean equals(Object o) {
733        return super.equals(o) && (o instanceof CourseRequest);
734    }
735    
736    /**
737     * Get reservations for this course requests
738     * @param course given course
739     * @return reservations for this course requests and the given course
740     */
741    public synchronized List<Reservation> getReservations(Course course) {
742        if (iReservations == null)
743            iReservations = new HashMap<Course, List<Reservation>>();
744        List<Reservation> reservations = iReservations.get(course);
745        if (reservations == null) {
746            reservations = new ArrayList<Reservation>();
747            boolean mustBeUsed = false;
748            for (Reservation r: course.getOffering().getReservations()) {
749                if (!r.isApplicable(getStudent())) continue;
750                if (!mustBeUsed && r.mustBeUsed()) { reservations.clear(); mustBeUsed = true; }
751                if (mustBeUsed && !r.mustBeUsed()) continue;
752                reservations.add(r);
753            }
754            iReservations.put(course, reservations);
755        }
756        return reservations;
757    }
758    private Map<Course, List<Reservation>> iReservations = null;
759    
760    /**
761     * Get reservations for this course requests ordered using {@link Reservation#compareTo(Assignment, Reservation)}
762     * @param course given course
763     * @return reservations for this course requests and the given course
764     */
765    public TreeSet<Reservation> getSortedReservations(Assignment<Request, Enrollment> assignment, Course course) {
766        TreeSet<Reservation> reservations = new TreeSet<Reservation>(new AssignmentComparator<Reservation, Request, Enrollment>(assignment));
767        reservations.addAll(getReservations(course));
768        return reservations;
769    }
770    
771    /**
772     * Return true if there is a reservation for a course of this request
773     * @return true if there is a reservation for a course of this request
774     */
775    public boolean hasReservations() {
776        for (Course course: getCourses())
777            if (!getReservations(course).isEmpty())
778                return true;
779        return false;
780    }
781    
782    /**
783     * Clear reservation information that was cached on this section
784     */
785    public synchronized void clearReservationCache() {
786        if (iReservations != null) iReservations.clear();
787    }
788    
789    /**
790     * Return true if this request can track MPP
791     * @return true if the request is course request and it either has an initial enrollment or some selected choices.
792     */
793    @Override
794    public boolean isMPP() {
795        StudentSectioningModel model = (StudentSectioningModel) getModel();
796        if (model == null || !model.isMPP()) return false;
797        return !getStudent().isDummy() && (getInitialAssignment() != null || !getSelectedChoices().isEmpty()); 
798    }
799    
800    /**
801     * Return true if this request has any selection
802     * @return true if the request is course request and has some selected choices.
803     */
804    @Override
805    public boolean hasSelection() {
806        if (getStudent().isDummy() || getSelectedChoices().isEmpty()) return false;
807        for (Choice choice: getSelectedChoices())
808            if (choice.getSectionId() != null || choice.getConfigId() != null) return true;
809        return false;
810    }
811    
812    /**
813     * Add request group to this request.
814     * @param group request group to be added
815     */
816    public void addRequestGroup(RequestGroup group) {
817        iRequestGroups.add(group);
818        group.addRequest(this);
819    }
820    
821    /**
822     * Removed request group from this request.
823     * @param group request group to be removed
824     */
825    public void removeRequestGroup(RequestGroup group) {
826        iRequestGroups.remove(group);
827        group.removeRequest(this);
828    }
829
830    /**
831     * Lists request groups of this request
832     * @return request groups of this course requests
833     */
834    public Set<RequestGroup> getRequestGroups() {
835        return iRequestGroups;
836    }
837    
838    @Override
839    public void variableAssigned(Assignment<Request, Enrollment> assignment, long iteration, Enrollment enrollment) {
840        super.variableAssigned(assignment, iteration, enrollment);
841        for (RequestGroup g: getRequestGroups())
842            if (g.getCourse().equals(enrollment.getCourse()))
843                g.assigned(assignment, enrollment);
844    }
845
846    @Override
847    public void variableUnassigned(Assignment<Request, Enrollment> assignment, long iteration, Enrollment enrollment) {
848        super.variableUnassigned(assignment, iteration, enrollment);
849        for (RequestGroup g: getRequestGroups())
850            if (g.getCourse().equals(enrollment.getCourse()))
851                g.unassigned(assignment, enrollment);
852    }
853}