001    /*
002     * Copyright (c) 2005 Einar Pehrson <einar@pehrson.nu>.
003     *
004     * This file is part of
005     * CleanSheets - a spreadsheet application for the Java platform.
006     *
007     * CleanSheets is free software; you can redistribute it and/or modify
008     * it under the terms of the GNU General Public License as published by
009     * the Free Software Foundation; either version 2 of the License, or
010     * (at your option) any later version.
011     *
012     * CleanSheets is distributed in the hope that it will be useful,
013     * but WITHOUT ANY WARRANTY; without even the implied warranty of
014     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
015     * GNU General Public License for more details.
016     *
017     * You should have received a copy of the GNU General Public License
018     * along with CleanSheets; if not, write to the Free Software
019     * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
020     */
021    package csheets.core.formula;
022    
023    import java.io.Serializable;
024    
025    import csheets.core.Value;
026    
027    /**
028     * An operator in a formula.
029     * @author Einar Pehrson
030     */
031    public interface Operator extends Serializable {
032    
033            /**
034             * Returns the operator's string identirifer.
035             * @return a string representation of the operator.
036             */
037            public String getIdentifier();
038    
039            /**
040             * Returns the type of value that the operator's operands can have.
041             * @return the type of value that the operator's operands can have
042             */
043            public Value.Type getOperandValueType();
044    }