001package net.sf.cpsolver.ifs.model;
002
003import java.util.Set;
004
005/**
006 * IFS constraint listener.
007 * 
008 * @see Constraint
009 * 
010 * @version IFS 1.2 (Iterative Forward Search)<br>
011 *          Copyright (C) 2006 - 2010 Tomáš Müller<br>
012 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
013 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
014 * <br>
015 *          This library is free software; you can redistribute it and/or modify
016 *          it under the terms of the GNU Lesser General Public License as
017 *          published by the Free Software Foundation; either version 3 of the
018 *          License, or (at your option) any later version. <br>
019 * <br>
020 *          This library is distributed in the hope that it will be useful, but
021 *          WITHOUT ANY WARRANTY; without even the implied warranty of
022 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
023 *          Lesser General Public License for more details. <br>
024 * <br>
025 *          You should have received a copy of the GNU Lesser General Public
026 *          License along with this library; if not see
027 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
028 */
029public interface ConstraintListener<T extends Value<?, T>> {
030    /**
031     * Called by the constraint, before a value is assigned to its variable.
032     * 
033     * @param iteration
034     *            current iteration
035     * @param constraint
036     *            source constraint
037     * @param assigned
038     *            value which will be assigned to its variable (
039     *            {@link Value#variable()})
040     * @param unassigned
041     *            set of conflicting values which will be unassigned by the
042     *            constraint before it assigns the given value
043     */
044    public void constraintBeforeAssigned(long iteration, Constraint<?, T> constraint, T assigned, Set<T> unassigned);
045
046    /**
047     * Called by the constraint, after a value is assigned to its variable.
048     * 
049     * @param iteration
050     *            current iteration
051     * @param constraint
052     *            source constraint
053     * @param assigned
054     *            value which was assigned to its variable (
055     *            {@link Value#variable()})
056     * @param unassigned
057     *            set of conflicting values which were unassigned by the
058     *            constraint before it assigned the given value
059     */
060    public void constraintAfterAssigned(long iteration, Constraint<?, T> constraint, T assigned, Set<T> unassigned);
061}