/**
* =========================================
* LibFormula : a free Java formula library
* =========================================
*
* Project Info: http://reporting.pentaho.org/libformula/
*
* (C) Copyright 2006-2007, by Pentaho Corporation and Contributors.
*
* This library is free software; you can redistribute it and/or modify it under the terms
* of the GNU Lesser General Public License as published by the Free Software Foundation;
* either version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
*
* ------------
* $Id: EvenFunction.java,v 1.1 2007/05/18 14:36:57 mimil Exp $
* ------------
* (C) Copyright 2006-2007, by Pentaho Corporation.
*/
package org.jfree.formula.function.math;
import org.jfree.formula.EvaluationException;
import org.jfree.formula.FormulaContext;
import org.jfree.formula.LibFormulaErrorValue;
import org.jfree.formula.function.Function;
import org.jfree.formula.function.ParameterCallback;
import org.jfree.formula.lvalues.TypeValuePair;
import org.jfree.formula.typing.Type;
import org.jfree.formula.typing.coretypes.NumberType;
/**
* This function returns the rounding of a number up to the nearest even
* integer.
*
* @author Cedric Pronzato
*
*/
public class EvenFunction implements Function
{
public EvenFunction()
{
}
public TypeValuePair evaluate(FormulaContext context,
ParameterCallback parameters) throws EvaluationException
{
final int parameterCount = parameters.getParameterCount();
if (parameterCount < 1)
{
throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
}
final Type type1 = parameters.getType(0);
final Object value1 = parameters.getValue(0);
final Number result = context.getTypeRegistry().convertToNumber(type1,
value1);
final int intValue = result.intValue();
Integer ret = null;
int test = intValue;
if (intValue < 0)
{
test = intValue * -1;
}
if (test % 2 == 0) // even
{
if (intValue == 0)
{
if (result.doubleValue() < 0)
{
ret = new Integer(-2);
}
else if (result.doubleValue() > 0)
{
ret = new Integer(2);
}
else
{
ret = new Integer(0);
}
}
else
{
ret = new Integer(intValue);
}
}
else
// odd
{
if (result.doubleValue() < 0)
{
ret = new Integer(intValue - 1);
}
else
{
ret = new Integer(intValue + 1);
}
}
return new TypeValuePair(NumberType.GENERIC_NUMBER, ret);
}
public String getCanonicalName()
{
return "EVEN";
}
}