    001package org.cpsolver.ifs.assignment;
    002
    003import java.util.Collection;
    004import java.util.HashMap;
    005import java.util.Map;
    006import java.util.concurrent.locks.Lock;
    007
    008import org.cpsolver.ifs.assignment.context.AssignmentContextHolder;
    009import org.cpsolver.ifs.assignment.context.DefaultParallelAssignmentContextHolder;
    010import org.cpsolver.ifs.model.Model;
    011import org.cpsolver.ifs.model.Value;
    012import org.cpsolver.ifs.model.Variable;
    013import org.cpsolver.ifs.solution.Solution;
    014import org.cpsolver.ifs.solver.ParallelSolver;
    015
    016
    017/**
    018 * An assignment using the {@link Variable#getAssignments()} to store values of all the
    019 * variables of the model. Besides of that, a set of assigned variables is kept in memory.
    020 * Each extra contains an array of values, indexed by {@link Assignment#getIndex()}.
    021 * Useful for a small, fixed number of assignments. Used by the {@link ParallelSolver},
    022 * where there is one assignment for each thread.
    023 *
    024 * @see Assignment
    025 * @see ParallelSolver
    026 *
    027 * @author  Tomáš Müller
    028 * @version IFS 1.3 (Iterative Forward Search)<br>
    029 *          Copyright (C) 2014 Tomáš Müller<br>
    030 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    031 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    032 * <br>
    033 *          This library is free software; you can redistribute it and/or modify
    034 *          it under the terms of the GNU Lesser General Public License as
    035 *          published by the Free Software Foundation; either version 3 of the
    036 *          License, or (at your option) any later version. <br>
    037 * <br>
    038 *          This library is distributed in the hope that it will be useful, but
    039 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    040 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    041 *          Lesser General Public License for more details. <br>
    042 * <br>
    043 *          You should have received a copy of the GNU Lesser General Public
    044 *          License along with this library; if not see <a href='http://www.gnu.org/licenses'>http://www.gnu.org/licenses</a>.
    045 * @param <V> Variable
    046 * @param <T> Value
    047 **/
    048public class DefaultParallelAssignment <V extends Variable<V, T>, T extends Value<V, T>> extends AssignmentAbstract<V, T> {
    049    private Map<V, Long> iAssignedVariables = new HashMap<V, Long>();
    050    private int iIndex;
    051
    052    public DefaultParallelAssignment(int threadIndex) {
    053        super(new DefaultParallelAssignmentContextHolder<V, T>(threadIndex));
    054        iIndex = threadIndex;
    055    }
    056
    057    public DefaultParallelAssignment() {
    058        this(0);
    059    }
    060
    061    public DefaultParallelAssignment(int threadIndex, Model<V, T> model, Assignment<V, T> assignment) {
    062        this(threadIndex);
    063        for (V variable: model.variables())
    064            setValueInternal(0, variable, assignment != null ? assignment.getValue(variable) : null);
    065    }
    066
    067    public DefaultParallelAssignment(AssignmentContextHolder<V, T> contexts, int threadIndex, Solution<V, T> solution) {
    068        super(contexts);
    069        iIndex = threadIndex;
    070        Lock lock = solution.getLock().readLock();
    071        lock.lock();
    072        try {
    073            for (V variable: solution.getModel().variables())
    074                setValueInternal(0, variable, solution.getAssignment().getValue(variable));
    075        } finally {
    076            lock.unlock();
    077        }
    078    }
    079
    080    @Override
    081    public long getIteration(V variable) {
    082        Long it = iAssignedVariables.get(variable);
    083        return (it == null ? 0 : it.longValue());
    084    }
    085
    086    @Override
    087    public Collection<V> assignedVariables() {
    088        return iAssignedVariables.keySet();
    089    }
    090
    091    @Override
    092    @SuppressWarnings({ "deprecation", "unchecked" })
    093    protected T getValueInternal(V variable) {
    094        return (T) variable.getAssignments()[iIndex];
    095    }
    096
    097    @Override
    098    @SuppressWarnings("deprecation")
    099    protected void setValueInternal(long iteration, V variable, T value) {
    100        variable.getAssignments()[iIndex] = value;
    101        if (value == null)
    102            iAssignedVariables.remove(variable);
    103        else
    104            iAssignedVariables.put(variable, iteration);
    105    }
    106
    107    @Override
    108    public int getIndex() {
    109        return iIndex;
    110    }
    111}