    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.CourseRequest;
    008import org.cpsolver.studentsct.model.Enrollment;
    009import org.cpsolver.studentsct.model.Request;
    010import org.cpsolver.studentsct.model.Section;
    011
    012
    013/**
    014 * Required sections constraint. This global constraint ensures that no enrollment
    015 * containing a prohibited section (using {@link CourseRequest#isRequired(Section)}) is used.
    016 *
    017 * @version StudentSct 1.3 (Student Sectioning)<br>
    018 *          Copyright (C) 2014 Tomáš Müller<br>
    019 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    020 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    021 * <br>
    022 *          This library is free software; you can redistribute it and/or modify
    023 *          it under the terms of the GNU Lesser General Public License as
    024 *          published by the Free Software Foundation; either version 3 of the
    025 *          License, or (at your option) any later version. <br>
    026 * <br>
    027 *          This library is distributed in the hope that it will be useful, but
    028 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    029 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    030 *          Lesser General Public License for more details. <br>
    031 * <br>
    032 *          You should have received a copy of the GNU Lesser General Public
    033 *          License along with this library; if not see
    034 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
    035 */
    036public class RequiredSections extends GlobalConstraint<Request, Enrollment> {
    037
    038    /**
    039     * A given enrollment is conflicting, if there is a section that
    040     * is cancelled.
    041     *
    042     * @param enrollment {@link Enrollment} that is being considered
    043     * @param conflicts all computed conflicting requests are added into this set
    044     */
    045    @Override
    046    public void computeConflicts(Assignment<Request, Enrollment> assignment, Enrollment enrollment, Set<Enrollment> conflicts) {
    047        if (inConflict(assignment, enrollment))
    048            conflicts.add(enrollment);
    049    }
    050
    051    /**
    052     * A given enrollment is conflicting, if there is a section that
    053     * is cancelled.
    054     *
    055     * @param enrollment {@link Enrollment} that is being considered
    056     * @return true, if the enrollment does not follow a reservation that must be used
    057     */
    058    @Override
    059    public boolean inConflict(Assignment<Request, Enrollment> assignment, Enrollment enrollment) {
    060        // exclude free time requests
    061        if (enrollment.getConfig() == null) return false;
    062
    063        // check all sections of the given enrollment
    064        CourseRequest cr = (CourseRequest)enrollment.variable();
    065        for (Section section: enrollment.getSections())
    066            if (!cr.isRequired(section)) return true;
    067
    068        return false;
    069    }
    070
    071    @Override
    072    public String toString() {
    073        return "RequiredSections";
    074    }
    075}