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: MaxFunction.java 3521 2007-10-16 10:55:14Z tmorgner $
028 * ------------
029 * (C) Copyright 2006-2007, by Pentaho Corporation.
030 */
031 package org.jfree.formula.function.math;
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.util.NumberUtil;
039 import org.jfree.formula.function.Function;
040 import org.jfree.formula.function.ParameterCallback;
041 import org.jfree.formula.lvalues.TypeValuePair;
042 import org.jfree.formula.typing.Type;
043 import org.jfree.formula.typing.sequence.NumberSequence;
044 import org.jfree.formula.typing.coretypes.NumberType;
045
046 /**
047 * This function returns the maximum from a set of numbers.
048 *
049 * @author Cedric Pronzato
050 *
051 */
052 public class MaxFunction implements Function
053 {
054 public static final BigDecimal ZERO = new BigDecimal(0);
055
056 public MaxFunction()
057 {
058 }
059
060 public TypeValuePair evaluate(final FormulaContext context, final ParameterCallback parameters) throws EvaluationException
061 {
062 final int parameterCount = parameters.getParameterCount();
063
064 if(parameterCount == 0)
065 {
066 return new TypeValuePair(NumberType.GENERIC_NUMBER, ZERO);
067 }
068
069 BigDecimal last = null;
070 for (int paramIdx = 0; paramIdx < parameterCount; paramIdx++)
071 {
072 final Type type = parameters.getType(paramIdx);
073 final Object value = parameters.getValue(paramIdx);
074 final NumberSequence sequence = context.getTypeRegistry().convertToNumberSequence(type, value);
075
076 while(sequence.hasNext())
077 {
078 final BigDecimal next = NumberUtil.getAsBigDecimal(sequence.nextNumber());
079 if(last == null)
080 {
081 last = next;
082 }
083 else
084 {
085 if(last.compareTo(next) == -1)
086 {
087 last = next;
088 }
089 }
090 }
091 }
092 if(last == null)
093 {
094 throw new EvaluationException(
095 LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
096 }
097
098 return new TypeValuePair(NumberType.GENERIC_NUMBER, last);
099 }
100
101 public String getCanonicalName()
102 {
103 return "MAX";
104 }
105
106 }