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 numeric sum of its arguments.
031 * @author Einar Pehrson
032 */
033 public class Sum implements Function {
034
035 /** The only (but repeatable) parameter: a numeric term */
036 public static final FunctionParameter[] parameters = new FunctionParameter[] {
037 new FunctionParameter(Value.Type.NUMERIC, "Term", false,
038 "A number to be included in the sum")
039 };
040
041 /**
042 * Creates a new instance of the SUM function.
043 */
044 public Sum() {}
045
046 public String getIdentifier() {
047 return "SUM";
048 }
049
050 public Value applyTo(Expression[] arguments) throws IllegalValueTypeException {
051 double sum = 0;
052 for (Expression expression : arguments) {
053 Value value = expression.evaluate();
054 if (value.getType() == Value.Type.NUMERIC)
055 sum += value.toDouble();
056 else if (value.getType() == Value.Type.MATRIX)
057 for (Value[] vector : value.toMatrix()) {
058 for (Value item : vector)
059 if (item.getType() == Value.Type.NUMERIC)
060 sum += item.toDouble();
061 else
062 throw new IllegalValueTypeException(item, Value.Type.NUMERIC);
063 } else
064 throw new IllegalValueTypeException(value, Value.Type.NUMERIC);
065 }
066 return new Value(sum);
067 }
068
069 public FunctionParameter[] getParameters() {
070 return parameters;
071 }
072
073 public boolean isVarArg() {
074 return true;
075 }
076 }