001    package net.sf.cpsolver.ifs.constant;
002    
003    /**
004     * Extension of a variable with the possibility to have a constant value.
005     * 
006     * Such variables are excluded from the solver process, however, 
007     * they can be included in constraints.
008     *
009     * @version
010     * IFS 1.1 (Iterative Forward Search)<br>
011     * Copyright (C) 2006 Tomáš Müller<br>
012     * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
013     * Lazenska 391, 76314 Zlin, Czech Republic<br>
014     * <br>
015     * This library is free software; you can redistribute it and/or
016     * modify it under the terms of the GNU Lesser General Public
017     * License as published by the Free Software Foundation; either
018     * version 2.1 of the License, or (at your option) any later version.
019     * <br><br>
020     * This library is distributed in the hope that it will be useful,
021     * but WITHOUT ANY WARRANTY; without even the implied warranty of
022     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
023     * Lesser General Public License for more details.
024     * <br><br>
025     * You should have received a copy of the GNU Lesser General Public
026     * License along with this library; if not, write to the Free Software
027     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
028     *  
029     */
030    
031    public interface ConstantVariable {
032            /** True, if the variable is constant. */
033            public boolean isConstant();
034    }