    001package org.cpsolver.studentsct.heuristics.selection;
    002
    003import org.apache.logging.log4j.Logger;
    004import org.cpsolver.ifs.assignment.Assignment;
    005import org.cpsolver.ifs.model.Neighbour;
    006import org.cpsolver.ifs.solution.Solution;
    007import org.cpsolver.ifs.solver.Solver;
    008import org.cpsolver.ifs.util.DataProperties;
    009import org.cpsolver.ifs.util.Progress;
    010import org.cpsolver.studentsct.heuristics.studentord.StudentOrder;
    011import org.cpsolver.studentsct.heuristics.studentord.StudentRandomOrder;
    012import org.cpsolver.studentsct.model.Enrollment;
    013import org.cpsolver.studentsct.model.Request;
    014import org.cpsolver.studentsct.model.Student;
    015
    016
    017/**
    018 * Resection incomplete studends. An extension of {@link BranchBoundSelection},
    019 * where only students that are not complete ({@link Student#isComplete(Assignment)} is
    020 * false) and that are sectioned somewhere ({@link Student#nrAssignedRequests(Assignment)}
    021 * is greater then zero) are resectioned.
    022 *
    023 * <br>
    024 * <br>
    025 *
    026 * @author  Tomáš Müller
    027 * @version StudentSct 1.3 (Student Sectioning)<br>
    028 *          Copyright (C) 2007 - 2014 Tomáš Müller<br>
    029 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    030 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    031 * <br>
    032 *          This library is free software; you can redistribute it and/or modify
    033 *          it under the terms of the GNU Lesser General Public License as
    034 *          published by the Free Software Foundation; either version 3 of the
    035 *          License, or (at your option) any later version. <br>
    036 * <br>
    037 *          This library is distributed in the hope that it will be useful, but
    038 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    039 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    040 *          Lesser General Public License for more details. <br>
    041 * <br>
    042 *          You should have received a copy of the GNU Lesser General Public
    043 *          License along with this library; if not see
    044 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
    045 */
    046
    047public class ResectionIncompleteStudentsSelection extends BranchBoundSelection {
    048    private static Logger sLog = org.apache.logging.log4j.LogManager.getLogger(ResectionIncompleteStudentsSelection.class);
    049
    050    public ResectionIncompleteStudentsSelection(DataProperties properties) {
    051        super(properties);
    052        iOrder = new StudentRandomOrder(properties);
    053        if (properties.getProperty("Neighbour.ResectionIncompleteStudentsOrder") != null) {
    054            try {
    055                iOrder = (StudentOrder) Class.forName(
    056                        properties.getProperty("Neighbour.ResectionIncompleteStudentsOrder")).getConstructor(
    057                        new Class[] { DataProperties.class }).newInstance(new Object[] { properties });
    058            } catch (Exception e) {
    059                sLog.error("Unable to set student order, reason:" + e.getMessage(), e);
    060            }
    061        }
    062    }
    063
    064    @Override
    065    public void init(Solver<Request, Enrollment> solver) {
    066        init(solver, "Resection incomplete students...");
    067    }
    068
    069    /**
    070     * Select neighbour. All students with an incomplete and non-empty schedule
    071     * are taken, one by one in a random order. For each student a branch &amp;
    072     * bound search is employed.
    073     */
    074    @Override
    075    public Neighbour<Request, Enrollment> selectNeighbour(Solution<Request, Enrollment> solution) {
    076        Student student = null;
    077        while ((student = nextStudent()) != null) {
    078            Progress.getInstance(solution.getModel()).incProgress();
    079            if (student.nrAssignedRequests(solution.getAssignment()) == 0 || student.isComplete(solution.getAssignment()))
    080                continue;
    081            Neighbour<Request, Enrollment> neighbour = getSelection(solution.getAssignment(), student).select();
    082            if (neighbour != null)
    083                return neighbour;
    084        }
    085        return null;
    086    }
    087
    088}