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, they can be
007     * included in constraints.
008     * 
009     * @version IFS 1.2 (Iterative Forward Search)<br>
010     *          Copyright (C) 2006 - 2010 Tomas Muller<br>
011     *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
012     *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
013     * <br>
014     *          This library is free software; you can redistribute it and/or modify
015     *          it under the terms of the GNU Lesser General Public License as
016     *          published by the Free Software Foundation; either version 3 of the
017     *          License, or (at your option) any later version. <br>
018     * <br>
019     *          This library is distributed in the hope that it will be useful, but
020     *          WITHOUT ANY WARRANTY; without even the implied warranty of
021     *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
022     *          Lesser General Public License for more details. <br>
023     * <br>
024     *          You should have received a copy of the GNU Lesser General Public
025     *          License along with this library; if not see <http://www.gnu.org/licenses/>.
026     * 
027     */
028    
029    public interface ConstantVariable {
030        /** True, if the variable is constant. */
031        public boolean isConstant();
032    }