001    package net.sf.cpsolver.coursett.constraint;
002    
003    import java.util.Set;
004    
005    import net.sf.cpsolver.coursett.criteria.StudentConflict;
006    import net.sf.cpsolver.coursett.model.Lecture;
007    import net.sf.cpsolver.coursett.model.Placement;
008    import net.sf.cpsolver.ifs.model.Constraint;
009    
010    /**
011     * Ignore student conflicts constraint. <br>
012     * This constraint keeps track of classes between which student conflicts of any kind are to be ignored.
013     * This constraint is used by {@link Lecture#isToIgnoreStudentConflictsWith(Lecture)} and translates to
014     * {@link StudentConflict#ignore(Lecture, Lecture)} that is true when the two classes are connected by
015     * this constraint.
016     *   
017     * <br>
018     * 
019     * @version CourseTT 1.2 (University Course Timetabling)<br>
020     *          Copyright (C) 2013 Tomas Muller<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     */
038    public class IgnoreStudentConflictsConstraint extends Constraint<Lecture, Placement> {
039        
040        public static final String REFERENCE = "NO_CONFLICT";
041        
042        @Override
043        public void addVariable(Lecture variable) {
044            super.addVariable(variable);
045            variable.clearIgnoreStudentConflictsWithCache();
046        }
047    
048        @Override
049        public void computeConflicts(Placement value, Set<Placement> conflicts) {
050        }
051        
052        @Override
053        public boolean isHard() {
054            return false;
055        }
056    
057    }