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; 010 011/** 012 * Fixed assignment constraint. This global constraint checks that the 013 * conflicts that have been computed so far (by other global constraints earlier 014 * in the list) do not create a conflict with a fixed assignment. This constraint 015 * is to be used only when there are fixed course requests and it is to be last global constraint 016 * in the list. 017 * 018 * @version StudentSct 1.3 (Student Sectioning)<br> 019 * Copyright (C) 2007 - 2015 Tomáš Müller<br> 020 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br> 021 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br> 022 * <br> 023 * This library is free software; you can redistribute it and/or modify 024 * it under the terms of the GNU Lesser General Public License as 025 * published by the Free Software Foundation; either version 3 of the 026 * License, or (at your option) any later version. <br> 027 * <br> 028 * This library is distributed in the hope that it will be useful, but 029 * WITHOUT ANY WARRANTY; without even the implied warranty of 030 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 031 * Lesser General Public License for more details. <br> 032 * <br> 033 * You should have received a copy of the GNU Lesser General Public 034 * License along with this library; if not see 035 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>. 036 */ 037public class FixedAssignments extends GlobalConstraint<Request, Enrollment> { 038 039 /** 040 * If there is a conflict that is fixed (method {@link CourseRequest#isFixed()} returns true) 041 * and equal to the initial assignment (returned by {@link CourseRequest#getFixedValue()}), 042 * the given enrollment is put into the conflicts. 043 */ 044 @Override 045 public void computeConflicts(Assignment<Request, Enrollment> assignment, Enrollment enrollment, Set<Enrollment> conflicts) { 046 for (Enrollment conflict: conflicts) { 047 if (conflict.getRequest() instanceof CourseRequest) { 048 CourseRequest cr = (CourseRequest)conflict.getRequest(); 049 if (cr.isFixed() && conflict.equals(cr.getFixedValue())) { 050 conflicts.add(enrollment); 051 return; 052 } 053 } 054 } 055 } 056}