    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 * @version IFS 1.3 (Iterative Forward Search)<br>
    019 *          Copyright (C) 2014 Tomáš Müller<br>
    020 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    021 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    022 * <br>
    023 *          This library is free software; you can redistribute it and/or modify
    024 *          it under the terms of the GNU Lesser General Public License as
    025 *          published by the Free Software Foundation; either version 3 of the
    026 *          License, or (at your option) any later version. <br>
    027 * <br>
    028 *          This library is distributed in the hope that it will be useful, but
    029 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    030 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    031 *          Lesser General Public License for more details. <br>
    032 * <br>
    033 *          You should have received a copy of the GNU Lesser General Public
    034 *          License along with this library; if not see <a href='http://www.gnu.org/licenses'>http://www.gnu.org/licenses</a>.
    035 * @param <V> Variable
    036 * @param <T> Value
    037 **/
    038public class DefaultParallelAssignmentContextHolder<V extends Variable<V, T>, T extends Value<V, T>> extends AssignmentContextHolderMap<V, T> {
    039    protected int iIndex = -1;
    040
    041    public DefaultParallelAssignmentContextHolder(int threadIndex) {
    042        iIndex = threadIndex;
    043    }
    044
    045    @Override
    046    @SuppressWarnings("unchecked")
    047    public <U extends AssignmentContext> U getAssignmentContext(Assignment<V, T> assignment, AssignmentContextReference<V, T, U> reference) {
    048        if (iIndex >= 0 && iIndex < CanHoldContext.sMaxSize && reference.getParent() instanceof CanHoldContext) {
    049            AssignmentContext[] contexts = ((CanHoldContext)reference.getParent()).getContext();
    050            U context = (U)contexts[iIndex];
    051
    052            if (context == null) {
    053                context = reference.getParent().createAssignmentContext(assignment);
    054                contexts[iIndex] = context;
    055            }
    056
    057            return context;
    058        } else {
    059            return super.getAssignmentContext(assignment, reference);
    060        }
    061    }
    062
    063    @Override
    064    public <C extends AssignmentContext> void clearContext(AssignmentContextReference<V, T, C> reference) {
    065        if (iIndex >= 0 && iIndex < CanHoldContext.sMaxSize && reference.getParent() instanceof CanHoldContext) {
    066            AssignmentContext[] contexts = ((CanHoldContext)reference.getParent()).getContext();
    067            contexts[iIndex] = null;
    068        } else {
    069            super.clearContext(reference);
    070        }
    071    }
    072}