001package org.cpsolver.ifs.model;
002
003import java.util.Set;
004
005import org.cpsolver.ifs.assignment.Assignment;
006
007
008/**
009 * IFS constraint listener.
010 * 
011 * @see Constraint
012 * 
013 * @version IFS 1.3 (Iterative Forward Search)<br>
014 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
015 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
016 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
017 * <br>
018 *          This library is free software; you can redistribute it and/or modify
019 *          it under the terms of the GNU Lesser General Public License as
020 *          published by the Free Software Foundation; either version 3 of the
021 *          License, or (at your option) any later version. <br>
022 * <br>
023 *          This library is distributed in the hope that it will be useful, but
024 *          WITHOUT ANY WARRANTY; without even the implied warranty of
025 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
026 *          Lesser General Public License for more details. <br>
027 * <br>
028 *          You should have received a copy of the GNU Lesser General Public
029 *          License along with this library; if not see
030 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
031 * @param <V> Variable
032 * @param <T> Value
033 */
034public interface ConstraintListener<V extends Variable<V, T>, T extends Value<V, T>> {
035    /**
036     * Called by the constraint, before a value is assigned to its variable.
037     * 
038     * @param assignment current assignment
039     * @param iteration
040     *            current iteration
041     * @param constraint
042     *            source constraint
043     * @param assigned
044     *            value which will be assigned to its variable (
045     *            {@link Value#variable()})
046     * @param unassigned
047     *            set of conflicting values which will be unassigned by the
048     *            constraint before it assigns the given value
049     */
050    public void constraintBeforeAssigned(Assignment<V, T> assignment, long iteration, Constraint<V, T> constraint, T assigned, Set<T> unassigned);
051
052    /**
053     * Called by the constraint, after a value is assigned to its variable.
054     * 
055     * @param assignment current assignment
056     * @param iteration
057     *            current iteration
058     * @param constraint
059     *            source constraint
060     * @param assigned
061     *            value which was assigned to its variable (
062     *            {@link Value#variable()})
063     * @param unassigned
064     *            set of conflicting values which were unassigned by the
065     *            constraint before it assigned the given value
066     */
067    public void constraintAfterAssigned(Assignment<V, T> assignment, long iteration, Constraint<V, T> constraint, T assigned, Set<T> unassigned);
068}