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.lang;
022    
023    import csheets.core.IllegalValueTypeException;
024    import csheets.core.Value;
025    import csheets.core.formula.Expression;
026    import csheets.core.formula.Function;
027    import csheets.core.formula.FunctionParameter;
028    
029    /**
030     * A function that returns the boolean value true.
031     * @author Einar Pehrson
032     */
033    public class True implements Function {
034    
035            /** The empty parameter list */
036            public static final FunctionParameter[] parameters = new FunctionParameter[]{};
037    
038            /**
039             * Creates a new instance of the TRUE function.
040             */
041            public True() {}
042    
043            public String getIdentifier() {
044                    return "TRUE";
045            }
046    
047            public Value applyTo(Expression[] arguments) throws IllegalValueTypeException {
048                    return new Value(true);
049            }
050    
051            public FunctionParameter[] getParameters() {
052                    return parameters;
053            }
054    
055            public boolean isVarArg() {
056                    return false;
057            }
058    }