001 /** 002 * ========================================= 003 * LibFormula : a free Java formula library 004 * ========================================= 005 * 006 * Project Info: http://reporting.pentaho.org/libformula/ 007 * 008 * (C) Copyright 2006-2007, by Pentaho Corporation and Contributors. 009 * 010 * This library is free software; you can redistribute it and/or modify it under the terms 011 * of the GNU Lesser General Public License as published by the Free Software Foundation; 012 * either version 2.1 of the License, or (at your option) any later version. 013 * 014 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 015 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 016 * See the GNU Lesser General Public License for more details. 017 * 018 * You should have received a copy of the GNU Lesser General Public License along with this 019 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, 020 * Boston, MA 02111-1307, USA. 021 * 022 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 023 * in the United States and other countries.] 024 * 025 * 026 * ------------ 027 * $Id: ChooseFunction.java 2752 2007-04-10 14:10:41Z taqua $ 028 * ------------ 029 * (C) Copyright 2006-2007, by Pentaho Corporation. 030 */ 031 032 package org.jfree.formula.function.information; 033 034 import org.jfree.formula.EvaluationException; 035 import org.jfree.formula.FormulaContext; 036 import org.jfree.formula.LibFormulaErrorValue; 037 import org.jfree.formula.function.Function; 038 import org.jfree.formula.function.ParameterCallback; 039 import org.jfree.formula.lvalues.TypeValuePair; 040 import org.jfree.formula.typing.Type; 041 042 /** 043 * This function uses an index to return a value from a list of values. 044 * The first value index is 1, 2 for the second and so on. 045 * 046 * @author Cedric Pronzato 047 */ 048 public class ChooseFunction implements Function 049 { 050 public ChooseFunction() 051 { 052 } 053 054 public String getCanonicalName() 055 { 056 return "CHOOSE"; 057 } 058 059 public TypeValuePair evaluate(final FormulaContext context, 060 final ParameterCallback parameters) 061 throws EvaluationException 062 { 063 064 if(parameters.getParameterCount() <= 2) 065 { 066 throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE); 067 } 068 069 final Type indexType = parameters.getType(0); 070 final Object indexValue = parameters.getValue(0); 071 072 final int index= context.getTypeRegistry().convertToNumber(indexType, indexValue).intValue(); 073 if(index >= 1 && index < parameters.getParameterCount()) 074 { 075 return new TypeValuePair(parameters.getType(index), parameters.getValue(index)); 076 } 077 // else 078 throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE); 079 } 080 }