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 */
021package csheets.core.formula.lang;
022
023import csheets.core.IllegalValueTypeException;
024import csheets.core.Value;
025import csheets.core.formula.Expression;
026import csheets.core.formula.Function;
027import csheets.core.formula.FunctionParameter;
028
029/**
030 * A function that counts those of its arguments that yield numeric values.
031 * @author Einar Pehrson
032 */
033public 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}