    001package org.cpsolver.ifs.assignment;
    002
    003import java.util.Collection;
    004import java.util.HashSet;
    005import java.util.Set;
    006
    007import org.cpsolver.ifs.assignment.context.DefaultSingleAssignmentContextHolder;
    008import org.cpsolver.ifs.model.Model;
    009import org.cpsolver.ifs.model.Value;
    010import org.cpsolver.ifs.model.Variable;
    011import org.cpsolver.ifs.solver.Solver;
    012
    013
    014/**
    015 * An assignment using the old {@link Variable#getAssignment()} to store values of all the
    016 * variables of the model. Besides of that, a set of assigned variables is kept in memory.
    017 * It is fast, but there can be only one such assignment at a time.
    018 * Ideal for single threaded solvers. Also used as a default assignment, see
    019 * {@link Model#getDefaultAssignment()}. Used by {@link Solver} where there is only one
    020 * assignment kept in memory.
    021 *
    022 * @see Assignment
    023 * @see Solver
    024 *
    025 * @author  Tomáš Müller
    026 * @version IFS 1.3 (Iterative Forward Search)<br>
    027 *          Copyright (C) 2014 Tomáš Müller<br>
    028 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    029 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    030 * <br>
    031 *          This library is free software; you can redistribute it and/or modify
    032 *          it under the terms of the GNU Lesser General Public License as
    033 *          published by the Free Software Foundation; either version 3 of the
    034 *          License, or (at your option) any later version. <br>
    035 * <br>
    036 *          This library is distributed in the hope that it will be useful, but
    037 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    038 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    039 *          Lesser General Public License for more details. <br>
    040 * <br>
    041 *          You should have received a copy of the GNU Lesser General Public
    042 *          License along with this library; if not see <a href='http://www.gnu.org/licenses'>http://www.gnu.org/licenses</a>.
    043 * @param <V> Variable
    044 * @param <T> Value
    045 **/
    046public class DefaultSingleAssignment<V extends Variable<V, T>, T extends Value<V, T>> extends AssignmentAbstract<V, T> {
    047    private Set<V> iAssignedVariables = new HashSet<V>();
    048
    049    public DefaultSingleAssignment() {
    050        super(new DefaultSingleAssignmentContextHolder<V,T>());
    051    }
    052
    053    @Override
    054    @SuppressWarnings("deprecation")
    055    public long getIteration(V variable) {
    056        return variable.getLastIteration();
    057    }
    058
    059    @Override
    060    public Collection<V> assignedVariables() {
    061        return iAssignedVariables;
    062    }
    063
    064    @Override
    065    @SuppressWarnings("deprecation")
    066    protected T getValueInternal(V variable) {
    067        return variable.getAssignment();
    068    }
    069
    070    @Override
    071    @SuppressWarnings("deprecation")
    072    protected void setValueInternal(long iteration, V variable, T value) {
    073        variable.setAssignment(value);
    074        variable.setLastIteration(iteration);
    075        if (value == null)
    076            iAssignedVariables.remove(variable);
    077        else
    078            iAssignedVariables.add(variable);
    079    }
    080
    081    @Override
    082    public int getIndex() {
    083        return 0;
    084    }
    085}