001    package net.sf.cpsolver.ifs.model;
002    
003    import 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 Tomas Muller<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     */
029    public 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    }