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.Enrollment;
008import org.cpsolver.studentsct.model.FreeTimeRequest;
009import org.cpsolver.studentsct.model.Request;
010import org.cpsolver.studentsct.model.Student;
011
012/**
013 * A simple global constraint that does not allow an overlap with a higher
014 * priority free time request, even when it is not assigned.
015 * 
016 * @author  Tomáš Müller
017 * @version StudentSct 1.3 (Student Sectioning)<br>
018 *          Copyright (C) 2007 - 2026 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 FreeTimeConflicts extends GlobalConstraint<Request, Enrollment> {
037
038    @Override
039    public void computeConflicts(Assignment<Request, Enrollment> assignment, Enrollment value, Set<Enrollment> conflicts) {
040        if (inConflict(assignment, value)) conflicts.add(value);
041    }
042    
043    @Override
044    public boolean inConflict(Assignment<Request, Enrollment> assignment, Enrollment value) {
045        if (value.isAllowOverlap()) return false;
046        Student student = value.getRequest().getStudent();
047        for (Request request: student.getRequests()) {
048            if (request.equals(value.getRequest())) break;
049            if (request instanceof FreeTimeRequest) {
050                FreeTimeRequest ft = (FreeTimeRequest)request;
051                if (ft.isOverlapping(value.getSections())) return true;
052            }
053        }
054        return false;
055    }
056
057}