    001package org.cpsolver.ifs.assignment.context;
    002
    003import org.cpsolver.ifs.assignment.Assignment;
    004import org.cpsolver.ifs.assignment.DefaultParallelAssignment;
    005import org.cpsolver.ifs.model.Value;
    006import org.cpsolver.ifs.model.Variable;
    007
    008
    009/**
    010 * A simple assignment context holder implementation used by the {@link DefaultParallelAssignment} class.
    011 * {@link CanHoldContext} are used when possible, storing contexts in arrays, on the
    012 * {@link DefaultParallelAssignment#getIndex()} position.
    013 *
    014 * @see AssignmentContext
    015 * @see AssignmentContextReference
    016 * @see AssignmentContextHolder
    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 DefaultParallelAssignmentContextHolder<V extends Variable<V, T>, T extends Value<V, T>> extends AssignmentContextHolderMap<V, T> {
    040    protected int iIndex = -1;
    041
    042    public DefaultParallelAssignmentContextHolder(int threadIndex) {
    043        iIndex = threadIndex;
    044    }
    045
    046    @Override
    047    @SuppressWarnings("unchecked")
    048    public <U extends AssignmentContext> U getAssignmentContext(Assignment<V, T> assignment, AssignmentContextReference<V, T, U> reference) {
    049        if (iIndex >= 0 && iIndex < CanHoldContext.sMaxSize && reference.getParent() instanceof CanHoldContext) {
    050            AssignmentContext[] contexts = ((CanHoldContext)reference.getParent()).getContext();
    051            U context = (U)contexts[iIndex];
    052
    053            if (context == null) {
    054                context = reference.getParent().createAssignmentContext(assignment);
    055                contexts[iIndex] = context;
    056            }
    057
    058            return context;
    059        } else {
    060            return super.getAssignmentContext(assignment, reference);
    061        }
    062    }
    063
    064    @Override
    065    public <C extends AssignmentContext> void clearContext(AssignmentContextReference<V, T, C> reference) {
    066        if (iIndex >= 0 && iIndex < CanHoldContext.sMaxSize && reference.getParent() instanceof CanHoldContext) {
    067            AssignmentContext[] contexts = ((CanHoldContext)reference.getParent()).getContext();
    068            contexts[iIndex] = null;
    069        } else {
    070            super.clearContext(reference);
    071        }
    072    }
    073}