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 * @author  Tomáš Müller
014 * @version IFS 1.3 (Iterative Forward Search)<br>
015 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
016 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
017 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
018 * <br>
019 *          This library is free software; you can redistribute it and/or modify
020 *          it under the terms of the GNU Lesser General Public License as
021 *          published by the Free Software Foundation; either version 3 of the
022 *          License, or (at your option) any later version. <br>
023 * <br>
024 *          This library is distributed in the hope that it will be useful, but
025 *          WITHOUT ANY WARRANTY; without even the implied warranty of
026 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
027 *          Lesser General Public License for more details. <br>
028 * <br>
029 *          You should have received a copy of the GNU Lesser General Public
030 *          License along with this library; if not see
031 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
032 * @param <V> Variable
033 * @param <T> Value
034 */
035public interface ConstraintListener<V extends Variable<V, T>, T extends Value<V, T>> {
036    /**
037     * Called by the constraint, before a value is assigned to its variable.
038     * 
039     * @param assignment current assignment
040     * @param iteration
041     *            current iteration
042     * @param constraint
043     *            source constraint
044     * @param assigned
045     *            value which will be assigned to its variable (
046     *            {@link Value#variable()})
047     * @param unassigned
048     *            set of conflicting values which will be unassigned by the
049     *            constraint before it assigns the given value
050     */
051    public void constraintBeforeAssigned(Assignment<V, T> assignment, long iteration, Constraint<V, T> constraint, T assigned, Set<T> unassigned);
052
053    /**
054     * Called by the constraint, after a value is assigned to its variable.
055     * 
056     * @param assignment current assignment
057     * @param iteration
058     *            current iteration
059     * @param constraint
060     *            source constraint
061     * @param assigned
062     *            value which was assigned to its variable (
063     *            {@link Value#variable()})
064     * @param unassigned
065     *            set of conflicting values which were unassigned by the
066     *            constraint before it assigned the given value
067     */
068    public void constraintAfterAssigned(Assignment<V, T> assignment, long iteration, Constraint<V, T> constraint, T assigned, Set<T> unassigned);
069}