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}