001package net.sf.cpsolver.ifs.model;
002
003/**
004 * Interface of a constraint that weakens with the time.
005 * 
006 * @version CourseTT 1.2 (University Course Timetabling)<br>
007 *          Copyright (C) 2006 - 2010 Tomáš Müller<br>
008 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
009 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
010 * <br>
011 *          This library is free software; you can redistribute it and/or modify
012 *          it under the terms of the GNU Lesser General Public License as
013 *          published by the Free Software Foundation; either version 3 of the
014 *          License, or (at your option) any later version. <br>
015 * <br>
016 *          This library is distributed in the hope that it will be useful, but
017 *          WITHOUT ANY WARRANTY; without even the implied warranty of
018 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
019 *          Lesser General Public License for more details. <br>
020 * <br>
021 *          You should have received a copy of the GNU Lesser General Public
022 *          License along with this library; if not see
023 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
024 */
025
026public interface WeakeningConstraint<V extends Variable<V, T>, T extends Value<V, T>> {
027    /**
028     * Weaken the constraint. This method is called if the constraint
029     * participates in an unassigned of a variable.
030     */
031    public void weaken();
032    
033    
034    /**
035     * Weaken the constraint enough so that it can assign the given
036     * value.
037     */
038    public void weaken(T value);
039}