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 counts those of its arguments that yield numeric values.
031     * @author Einar Pehrson
032     */
033    public class Count implements Function {
034    
035            /** The function's parameters */
036            public static final FunctionParameter[] parameters = new FunctionParameter[] {
037                    new FunctionParameter(Value.Type.UNDEFINED, "Expression", false,
038                            "An expression whose value is checked for type compliance")
039                    /* new FunctionParameter(Value.Type.TEXT, "Type", true,
040                            'The type to look for. Accepted values are "NUMERIC" (default),'
041                            + '"TEXT", "BOOLEAN", "DATE", "MATRIX" and "ERROR".'); */
042            };
043    
044            /**
045             * Creates a new instance of the COUNT function.
046             */
047            public Count() {}
048    
049            public String getIdentifier() {
050                    return "COUNT";
051            }
052    
053            public Value applyTo(Expression[] arguments) throws IllegalValueTypeException {
054                    double count = 0;
055                    for (Expression expression : arguments) {
056                            Value value = expression.evaluate();
057                            if (value.getType() == Value.Type.NUMERIC)
058                                    count++;
059                    }
060                    return new Value(count);
061            }
062    
063            public FunctionParameter[] getParameters() {
064                    return parameters;
065            }
066    
067            public boolean isVarArg() {
068                    return true;
069            }
070    }