    001package org.cpsolver.ifs.assignment.context;
    002
    003import org.cpsolver.ifs.assignment.Assignment;
    004import org.cpsolver.ifs.model.Model;
    005import org.cpsolver.ifs.model.Value;
    006import org.cpsolver.ifs.model.Variable;
    007
    008/**
    009 * A variable with an assignment context. In order to be able to hold multiple assignments in memory
    010 * it is desired for all the assignment dependent data a variable may need (to effectively enumerate
    011 * its objectives), to store these data in a separate class (implementing the
    012 * {@link AssignmentContext} interface). This context is created by calling
    013 * {@link ConstraintWithContext#createAssignmentContext(Assignment)} and accessed by
    014 * {@link ConstraintWithContext#getContext(Assignment)}.
    015 *
    016 *
    017 * @see AssignmentContext
    018 *
    019 * @author  Tomáš Müller
    020 * @version IFS 1.3 (Iterative Forward Search)<br>
    021 *          Copyright (C) 2014 Tomáš Müller<br>
    022 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    023 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    024 * <br>
    025 *          This library is free software; you can redistribute it and/or modify
    026 *          it under the terms of the GNU Lesser General Public License as
    027 *          published by the Free Software Foundation; either version 3 of the
    028 *          License, or (at your option) any later version. <br>
    029 * <br>
    030 *          This library is distributed in the hope that it will be useful, but
    031 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    032 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    033 *          Lesser General Public License for more details. <br>
    034 * <br>
    035 *          You should have received a copy of the GNU Lesser General Public
    036 *          License along with this library; if not see <a href='http://www.gnu.org/licenses'>http://www.gnu.org/licenses</a>.
    037 * @param <V> Variable
    038 * @param <T> Value
    039 * @param <C> Assignment Context
    040 **/
    041public abstract class VariableWithContext<V extends Variable<V, T>, T extends Value<V, T>, C extends AssignmentContext> extends Variable<V, T> implements HasAssignmentContext<V, T, C>, CanHoldContext {
    042    private AssignmentContextReference<V, T, C> iContextReference = null;
    043    private AssignmentContext[] iContext = new AssignmentContext[CanHoldContext.sMaxSize];
    044
    045    /** Constructor */
    046    public VariableWithContext() {
    047        super();
    048    }
    049
    050    /**
    051     * Constructor
    052     * @param initialValue initial value (minimal-perturbation problem)
    053     */
    054    public VariableWithContext(T initialValue) {
    055        super(initialValue);
    056    }
    057
    058    @Override
    059    public void setModel(Model<V, T> model) {
    060        super.setModel(model);
    061        if (model != null)
    062            iContextReference = model.createReference(this);
    063    }
    064
    065    /**
    066     * Returns an assignment context associated with this extension. If there is no
    067     * assignment context associated with this extension yet, one is created using the
    068     * {@link ConstraintWithContext#createAssignmentContext(Assignment)} method. From that time on,
    069     * this context is kept with the assignment.
    070     * @param assignment given assignment
    071     * @return assignment context associated with this extension and the given assignment
    072     */
    073    @Override
    074    public C getContext(Assignment<V, T> assignment) {
    075        return AssignmentContextHelper.getContext(this, assignment);
    076    }
    077
    078    @Override
    079    public AssignmentContextReference<V, T, C> getAssignmentContextReference() { return iContextReference; }
    080
    081    @Override
    082    public void setAssignmentContextReference(AssignmentContextReference<V, T, C> reference) { iContextReference = reference; }
    083
    084    @Override
    085    public AssignmentContext[] getContext() { return iContext; }
    086}