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1: /** 2: * ========================================= 3: * LibFormula : a free Java formula library 4: * ========================================= 5: * 6: * Project Info: http://reporting.pentaho.org/libformula/ 7: * 8: * (C) Copyright 2006-2007, by Pentaho Corporation and Contributors. 9: * 10: * This library is free software; you can redistribute it and/or modify it under the terms 11: * of the GNU Lesser General Public License as published by the Free Software Foundation; 12: * either version 2.1 of the License, or (at your option) any later version. 13: * 14: * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 15: * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 16: * See the GNU Lesser General Public License for more details. 17: * 18: * You should have received a copy of the GNU Lesser General Public License along with this 19: * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, 20: * Boston, MA 02111-1307, USA. 21: * 22: * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 23: * in the United States and other countries.] 24: * 25: * 26: * ------------ 27: * $Id: EvenFunction.java 3521 2007-10-16 10:55:14Z tmorgner $ 28: * ------------ 29: * (C) Copyright 2006-2007, by Pentaho Corporation. 30: */ 31: package org.jfree.formula.function.math; 32: 33: import org.jfree.formula.EvaluationException; 34: import org.jfree.formula.FormulaContext; 35: import org.jfree.formula.LibFormulaErrorValue; 36: import org.jfree.formula.function.Function; 37: import org.jfree.formula.function.ParameterCallback; 38: import org.jfree.formula.lvalues.TypeValuePair; 39: import org.jfree.formula.typing.Type; 40: import org.jfree.formula.typing.coretypes.NumberType; 41: 42: /** 43: * This function returns the rounding of a number up to the nearest even 44: * integer. 45: * 46: * @author Cedric Pronzato 47: * 48: */ 49: public class EvenFunction implements Function 50: { 51: 52: public EvenFunction() 53: { 54: } 55: 56: public TypeValuePair evaluate(final FormulaContext context, 57: final ParameterCallback parameters) throws EvaluationException 58: { 59: final int parameterCount = parameters.getParameterCount(); 60: if (parameterCount < 1) 61: { 62: throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE); 63: } 64: final Type type1 = parameters.getType(0); 65: final Object value1 = parameters.getValue(0); 66: final Number result = context.getTypeRegistry().convertToNumber(type1, 67: value1); 68: 69: final int intValue = result.intValue(); 70: Integer ret; 71: 72: int test = intValue; 73: if (intValue < 0) 74: { 75: test = intValue * -1; 76: } 77: 78: if (test % 2 == 0) // even 79: { 80: if (intValue == 0) 81: { 82: if (result.doubleValue() < 0) 83: { 84: ret = new Integer(-2); 85: } 86: else if (result.doubleValue() > 0) 87: { 88: ret = new Integer(2); 89: } 90: else 91: { 92: ret = new Integer(0); 93: } 94: } 95: else 96: { 97: ret = new Integer(intValue); 98: } 99: } 100: else 101: // odd 102: { 103: if (result.doubleValue() < 0) 104: { 105: ret = new Integer(intValue - 1); 106: } 107: else 108: { 109: ret = new Integer(intValue + 1); 110: } 111: } 112: 113: return new TypeValuePair(NumberType.GENERIC_NUMBER, ret); 114: } 115: 116: public String getCanonicalName() 117: { 118: return "EVEN"; 119: } 120: 121: }