Frames | No Frames |
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: HourFunction.java 2822 2007-05-20 21:47:52Z mimil $ 28: * ------------ 29: * (C) Copyright 2006-2007, by Pentaho Corporation. 30: */ 31: package org.jfree.formula.function.datetime; 32: 33: import java.math.BigDecimal; 34: 35: import org.jfree.formula.EvaluationException; 36: import org.jfree.formula.FormulaContext; 37: import org.jfree.formula.LibFormulaErrorValue; 38: import org.jfree.formula.function.Function; 39: import org.jfree.formula.function.ParameterCallback; 40: import org.jfree.formula.lvalues.TypeValuePair; 41: import org.jfree.formula.typing.TypeRegistry; 42: import org.jfree.formula.typing.coretypes.NumberType; 43: import org.jfree.formula.util.NumberUtil; 44: 45: /** 46: * This function extracts the hour (0 through 23) from a time. 47: * 48: * @author Cedric Pronzato 49: */ 50: public class HourFunction implements Function 51: { 52: private static final BigDecimal HOUR_24 = new BigDecimal(24); 53: 54: public HourFunction() 55: { 56: } 57: 58: public String getCanonicalName() 59: { 60: return "HOUR"; 61: } 62: 63: public TypeValuePair evaluate(final FormulaContext context, 64: final ParameterCallback parameters) throws EvaluationException 65: { 66: if (parameters.getParameterCount() != 1) 67: { 68: throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE); 69: } 70: 71: final TypeRegistry typeRegistry = context.getTypeRegistry(); 72: final Number n = typeRegistry.convertToNumber(parameters.getType(0), 73: parameters.getValue(0)); 74: 75: if (n == null) 76: { 77: throw new EvaluationException( 78: LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE); 79: } 80: 81: final BigDecimal bd = NumberUtil.getAsBigDecimal(n); 82: final BigDecimal round1 = new BigDecimal(NumberUtil 83: .performIntRounding(bd).intValue()); 84: final BigDecimal dayFraction = bd.subtract(round1); 85: final Integer hour = NumberUtil.performIntRounding(dayFraction 86: .multiply(HOUR_24)); 87: 88: return new TypeValuePair(NumberType.GENERIC_NUMBER, hour); 89: } 90: }