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.reservation.Reservation; 011 012 013/** 014 * Required reservation constraint. This global constraint ensures that reservations 015 * with {@link Reservation#mustBeUsed()} flags are used. That is, an enrollment 016 * is conflicting when there is a reservation for the student that must be used, 017 * but the given enrollment does not use it. 018 * 019 * @version StudentSct 1.3 (Student Sectioning)<br> 020 * Copyright (C) 2014 Tomáš Müller<br> 021 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br> 022 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br> 023 * <br> 024 * This library is free software; you can redistribute it and/or modify 025 * it under the terms of the GNU Lesser General Public License as 026 * published by the Free Software Foundation; either version 3 of the 027 * License, or (at your option) any later version. <br> 028 * <br> 029 * This library is distributed in the hope that it will be useful, but 030 * WITHOUT ANY WARRANTY; without even the implied warranty of 031 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 032 * Lesser General Public License for more details. <br> 033 * <br> 034 * You should have received a copy of the GNU Lesser General Public 035 * License along with this library; if not see 036 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>. 037 */ 038public class RequiredReservation extends GlobalConstraint<Request, Enrollment> { 039 040 /** 041 * A given enrollment is conflicting, if there is a reservation that 042 * the student must use, but the given enrollment does not use it. 043 * 044 * @param enrollment {@link Enrollment} that is being considered 045 * @param conflicts all computed conflicting requests are added into this set 046 */ 047 @Override 048 public void computeConflicts(Assignment<Request, Enrollment> assignment, Enrollment enrollment, Set<Enrollment> conflicts) { 049 if (inConflict(assignment, enrollment)) 050 conflicts.add(enrollment); 051 } 052 053 /** 054 * A given enrollment is conflicting, if there is a reservation that 055 * the student must use, but the given enrollment does not use it. 056 * 057 * @param enrollment {@link Enrollment} that is being considered 058 * @return true, if the enrollment does not follow a reservation that must be used 059 */ 060 @Override 061 public boolean inConflict(Assignment<Request, Enrollment> assignment, Enrollment enrollment) { 062 // enrollment's config 063 Config config = enrollment.getConfig(); 064 065 // exclude free time requests 066 if (config == null) return false; 067 068 // no reservations 069 if (!config.getOffering().hasReservations()) 070 return false; 071 072 // enrollment's reservation 073 Reservation reservation = enrollment.getReservation(); 074 075 // already has a reservation that must be used 076 if (reservation != null && reservation.mustBeUsed()) return false; 077 078 // if a reservation is required for the student, fail 079 for (Reservation r: config.getOffering().getReservations()) 080 if (r.mustBeUsed() && r.isApplicable(enrollment.getStudent())) 081 return true; 082 083 return false; 084 } 085 086 @Override 087 public String toString() { 088 return "RequiredReservation"; 089 } 090}