    001package org.cpsolver.ifs.solver;
    002
    003import org.cpsolver.ifs.assignment.Assignment;
    004import org.cpsolver.ifs.model.Neighbour;
    005import org.cpsolver.ifs.model.Value;
    006import org.cpsolver.ifs.model.Variable;
    007
    008/**
    009 * IFS Solver Listener.
    010 *
    011 * @see Solver
    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 <a href='http://www.gnu.org/licenses'>http://www.gnu.org/licenses</a>.
    031 *
    032 * @param <V> Variable
    033 * @param <T> Value
    034 **/
    035public interface SolverListener<V extends Variable<V, T>, T extends Value<V, T>> {
    036
    037    /**
    038     * A variable was selected
    039     *
    040     * @param assignment current assignment
    041     * @param iteration
    042     *            current iteration
    043     * @param variable
    044     *            selected variable
    045     * @return if false is returned the variable will be discarded (search continues with the next variable selection)
    046     */
    047    public boolean variableSelected(Assignment<V, T> assignment, long iteration, V variable);
    048
    049    /**
    050     * A value was selected
    051     *
    052     * @param assignment current assignment
    053     * @param iteration
    054     *            current iteration
    055     * @param variable
    056     *            selected variable
    057     * @param value
    058     *            selected variable
    059     * @return if false is returned the selected value is not assigned
    060     */
    061    public boolean valueSelected(Assignment<V, T> assignment, long iteration, V variable, T value);
    062
    063    /**
    064     * A neighbour was selected
    065     *
    066     * @param assignment current assignment
    067     * @param iteration
    068     *            current iteration
    069     * @param neighbour
    070     *            neighbour
    071     * @return if false is returned the selected neighbour is not assigned
    072     */
    073    public boolean neighbourSelected(Assignment<V, T> assignment, long iteration, Neighbour<V, T> neighbour);
    074
    075    /**
    076     * Called when {@link ParallelSolver} failed to assign the given neighbour
    077     *
    078     * @param assignment current assignment
    079     * @param iteration
    080     *            current iteration
    081     * @param neighbour
    082     *            neighbour
    083     */
    084    public void neighbourFailed(Assignment<V, T> assignment, long iteration, Neighbour<V, T> neighbour);
    085
    086}