/*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This program 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.
*
* Copyright (c) 2006 - 2013 Pentaho Corporation and Contributors. All rights reserved.
*/
package org.pentaho.reporting.libraries.formula.function.math;
import org.pentaho.reporting.libraries.formula.EvaluationException;
import org.pentaho.reporting.libraries.formula.FormulaContext;
import org.pentaho.reporting.libraries.formula.LibFormulaErrorValue;
import org.pentaho.reporting.libraries.formula.function.Function;
import org.pentaho.reporting.libraries.formula.function.ParameterCallback;
import org.pentaho.reporting.libraries.formula.lvalues.TypeValuePair;
import org.pentaho.reporting.libraries.formula.typing.Type;
import org.pentaho.reporting.libraries.formula.typing.coretypes.NumberType;
import java.math.BigDecimal;
/**
* This function returns the rounding of a number up to the nearest even integer.
*
* @author Cedric Pronzato
*/
public class EvenFunction implements Function {
private static final long serialVersionUID = 2587673708222713810L;
public EvenFunction() {
}
public TypeValuePair evaluate( final FormulaContext context,
final ParameterCallback parameters ) throws EvaluationException {
final int parameterCount = parameters.getParameterCount();
if ( parameterCount < 1 ) {
throw EvaluationException.getInstance( 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 BigDecimal ret = compute( result );
return new TypeValuePair( NumberType.GENERIC_NUMBER, ret );
}
private static BigDecimal compute( final Number result ) {
final int intValue;
if ( result.doubleValue() < 0 ) {
intValue = (int) Math.floor( result.doubleValue() );
} else {
intValue = (int) Math.ceil( result.doubleValue() );
}
final BigDecimal ret;
if ( intValue % 2 == 0 ) // even
{
if ( intValue == 0 ) {
if ( result.doubleValue() < 0 ) {
ret = new BigDecimal( -2 );
} else if ( result.doubleValue() > 0 ) {
ret = new BigDecimal( 2 );
} else {
ret = new BigDecimal( 0 );
}
} else {
ret = new BigDecimal( intValue );
}
} else
// odd
{
if ( result.doubleValue() < 0 ) {
ret = new BigDecimal( intValue - 1 );
} else {
ret = new BigDecimal( intValue + 1 );
}
}
return ret;
}
public String getCanonicalName() {
return "EVEN";
}
}