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: HourFunction.java 2822 2007-05-20 21:47:52Z mimil $ 028 * ------------ 029 * (C) Copyright 2006-2007, by Pentaho Corporation. 030 */ 031 package org.jfree.formula.function.datetime; 032 033 import java.math.BigDecimal; 034 035 import org.jfree.formula.EvaluationException; 036 import org.jfree.formula.FormulaContext; 037 import org.jfree.formula.LibFormulaErrorValue; 038 import org.jfree.formula.function.Function; 039 import org.jfree.formula.function.ParameterCallback; 040 import org.jfree.formula.lvalues.TypeValuePair; 041 import org.jfree.formula.typing.TypeRegistry; 042 import org.jfree.formula.typing.coretypes.NumberType; 043 import org.jfree.formula.util.NumberUtil; 044 045 /** 046 * This function extracts the hour (0 through 23) from a time. 047 * 048 * @author Cedric Pronzato 049 */ 050 public class HourFunction implements Function 051 { 052 private static final BigDecimal HOUR_24 = new BigDecimal(24); 053 054 public HourFunction() 055 { 056 } 057 058 public String getCanonicalName() 059 { 060 return "HOUR"; 061 } 062 063 public TypeValuePair evaluate(final FormulaContext context, 064 final ParameterCallback parameters) throws EvaluationException 065 { 066 if (parameters.getParameterCount() != 1) 067 { 068 throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE); 069 } 070 071 final TypeRegistry typeRegistry = context.getTypeRegistry(); 072 final Number n = typeRegistry.convertToNumber(parameters.getType(0), 073 parameters.getValue(0)); 074 075 if (n == null) 076 { 077 throw new EvaluationException( 078 LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE); 079 } 080 081 final BigDecimal bd = NumberUtil.getAsBigDecimal(n); 082 final BigDecimal round1 = new BigDecimal(NumberUtil 083 .performIntRounding(bd).intValue()); 084 final BigDecimal dayFraction = bd.subtract(round1); 085 final Integer hour = NumberUtil.performIntRounding(dayFraction 086 .multiply(HOUR_24)); 087 088 return new TypeValuePair(NumberType.GENERIC_NUMBER, hour); 089 } 090 }