001package org.cpsolver.ifs.assignment;
002
003import java.util.ArrayList;
004import java.util.Collection;
005
006import org.cpsolver.ifs.assignment.context.AssignmentContextHolderMap;
007import org.cpsolver.ifs.model.Value;
008import org.cpsolver.ifs.model.Variable;
009
010
011/**
012 * An empty assignment. All variables are unassigned, any attempt to assign a 
013 * variable will throw the {@link UnsupportedOperationException} exception.<br><br>  
014 * 
015 * @author  Tomáš Müller
016 * @version IFS 1.3 (Iterative Forward Search)<br>
017 *          Copyright (C) 2014 Tomáš Müller<br>
018 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
019 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
020 * <br>
021 *          This library is free software; you can redistribute it and/or modify
022 *          it under the terms of the GNU Lesser General Public License as
023 *          published by the Free Software Foundation; either version 3 of the
024 *          License, or (at your option) any later version. <br>
025 * <br>
026 *          This library is distributed in the hope that it will be useful, but
027 *          WITHOUT ANY WARRANTY; without even the implied warranty of
028 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
029 *          Lesser General Public License for more details. <br>
030 * <br>
031 *          You should have received a copy of the GNU Lesser General Public
032 *          License along with this library; if not see <a href='http://www.gnu.org/licenses'>http://www.gnu.org/licenses</a>.
033 * @param <V> Variable
034 * @param <T> Value
035 **/
036public class EmptyAssignment<V extends Variable<V, T>, T extends Value<V, T>> extends AssignmentAbstract<V, T> {
037
038    public EmptyAssignment() {
039        super(new AssignmentContextHolderMap<V,T>());
040    }
041
042    @Override
043    public long getIteration(V variable) {
044        return 0;
045    }
046
047    @Override
048    public Collection<V> assignedVariables() {
049        return new ArrayList<V>();
050    }
051
052    @Override
053    protected T getValueInternal(V variable) {
054        return null;
055    }
056
057    @Override
058    protected void setValueInternal(long iteration, V variable, T value) {
059        throw new UnsupportedOperationException();
060    }
061}