    001package org.cpsolver.studentsct.constraint;
    002
    003import java.util.Set;
    004
    005import org.cpsolver.ifs.assignment.Assignment;
    006import org.cpsolver.ifs.model.GlobalConstraint;
    007import org.cpsolver.studentsct.model.Config;
    008import org.cpsolver.studentsct.model.Enrollment;
    009import org.cpsolver.studentsct.model.Request;
    010import org.cpsolver.studentsct.model.Section;
    011import org.cpsolver.studentsct.reservation.Reservation;
    012
    013
    014/**
    015 * Disabled sections constraint. This global constraint ensures that no enrollment
    016 * containing a disabled sections (using {@link Section#isEnabled()}) is used, unless
    017 * there is a reservation allowing for the use of disabled sections
    018 * (using {@link Reservation#isAllowDisabled()}).
    019 *
    020 * @author  Tomáš Müller
    021 * @version StudentSct 1.3 (Student Sectioning)<br>
    022 *          Copyright (C) 2014 Tomáš Müller<br>
    023 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    024 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    025 * <br>
    026 *          This library is free software; you can redistribute it and/or modify
    027 *          it under the terms of the GNU Lesser General Public License as
    028 *          published by the Free Software Foundation; either version 3 of the
    029 *          License, or (at your option) any later version. <br>
    030 * <br>
    031 *          This library is distributed in the hope that it will be useful, but
    032 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    033 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    034 *          Lesser General Public License for more details. <br>
    035 * <br>
    036 *          You should have received a copy of the GNU Lesser General Public
    037 *          License along with this library; if not see
    038 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
    039 */
    040public class DisabledSections extends GlobalConstraint<Request, Enrollment> {
    041
    042    /**
    043     * A given enrollment is conflicting, if there is a section that
    044     * is disabled and there is not a matching reservation that would allow for that.
    045     *
    046     * @param enrollment {@link Enrollment} that is being considered
    047     * @param conflicts all computed conflicting requests are added into this set
    048     */
    049    @Override
    050    public void computeConflicts(Assignment<Request, Enrollment> assignment, Enrollment enrollment, Set<Enrollment> conflicts) {
    051        if (inConflict(assignment, enrollment))
    052            conflicts.add(enrollment);
    053    }
    054
    055    /**
    056     * A given enrollment is conflicting, if there is a section that
    057     * is disabled and there is not a matching reservation that would allow for that.
    058     *
    059     * @param enrollment {@link Enrollment} that is being considered
    060     * @return true, if the enrollment does not follow a reservation that must be used
    061     */
    062    @Override
    063    public boolean inConflict(Assignment<Request, Enrollment> assignment, Enrollment enrollment) {
    064        // enrollment's config
    065        Config config = enrollment.getConfig();
    066
    067        // exclude free time requests
    068        if (config == null) return false;
    069
    070        // student allows for disabled sections >> no problem
    071        if (enrollment.getStudent().isAllowDisabled()) return false;
    072
    073        boolean hasDisabledSection = false;
    074        // check all sections of the given enrollment
    075        for (Section section: enrollment.getSections())
    076            if (!section.isEnabled(enrollment.getStudent())) {
    077                hasDisabledSection = true;
    078                break;
    079            }
    080
    081        // no disabled section >> no conflict
    082        if (!hasDisabledSection) return false;
    083
    084        // no reservations >> conflict not allowed
    085        if (!config.getOffering().hasReservations())
    086            return true;
    087
    088        // enrollment's reservation
    089        Reservation reservation = enrollment.getReservation();
    090
    091        // already has a reservation that all for disabled sections
    092        if (reservation != null && reservation.isAllowDisabled()) return false;
    093
    094        // if a there is some other reservation that allows for disabled sections >> also fine
    095        for (Reservation r: config.getOffering().getReservations())
    096            if (r.isAllowDisabled() && r.isApplicable(enrollment.getStudent(), enrollment.getCourse()) && r.isIncluded(enrollment))
    097                return false;
    098
    099        return true;
    100    }
    101
    102    @Override
    103    public String toString() {
    104        return "DisabledSections";
    105    }
    106}