    001package org.cpsolver.ifs.assignment.context;
    002
    003import java.util.HashMap;
    004import java.util.Map;
    005
    006import org.cpsolver.ifs.assignment.Assignment;
    007import org.cpsolver.ifs.model.Value;
    008import org.cpsolver.ifs.model.Variable;
    009
    010
    011/**
    012 * A simple assignment context holder implementation using {@link HashMap} to store all the assignment contexts.
    013 * {@link AssignmentContextReference#getIndex()} are used to index the map.
    014 *
    015 * @see AssignmentContext
    016 * @see AssignmentContextReference
    017 *
    018 * @author  Tomáš Müller
    019 * @version IFS 1.3 (Iterative Forward Search)<br>
    020 *          Copyright (C) 2014 Tomáš Müller<br>
    021 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    022 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    023 * <br>
    024 *          This library is free software; you can redistribute it and/or modify
    025 *          it under the terms of the GNU Lesser General Public License as
    026 *          published by the Free Software Foundation; either version 3 of the
    027 *          License, or (at your option) any later version. <br>
    028 * <br>
    029 *          This library is distributed in the hope that it will be useful, but
    030 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    031 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    032 *          Lesser General Public License for more details. <br>
    033 * <br>
    034 *          You should have received a copy of the GNU Lesser General Public
    035 *          License along with this library; if not see <a href='http://www.gnu.org/licenses'>http://www.gnu.org/licenses</a>.
    036 * @param <V> Variable
    037 * @param <T> Value
    038 **/
    039public class AssignmentContextHolderMap<V extends Variable<V, T>, T extends Value<V, T>> implements AssignmentContextHolder<V, T> {
    040    protected Map<Integer,AssignmentContext> iContexts = new HashMap<Integer, AssignmentContext>();
    041
    042    public AssignmentContextHolderMap() {
    043    }
    044
    045    @Override
    046    @SuppressWarnings("unchecked")
    047    public <U extends AssignmentContext> U getAssignmentContext(Assignment<V, T> assignment, AssignmentContextReference<V, T, U> reference) {
    048        U context = (U) iContexts.get(reference.getIndex());
    049        if (context != null) return context;
    050
    051        context = reference.getParent().createAssignmentContext(assignment);
    052        iContexts.put(reference.getIndex(), context);
    053        return context;
    054    }
    055
    056    @Override
    057    public <C extends AssignmentContext> void clearContext(AssignmentContextReference<V, T, C> reference) {
    058        iContexts.remove(reference.getIndex());
    059    }
    060
    061}