/**
* =========================================
* LibFormula : a free Java formula library
* =========================================
*
* Project Info: http://reporting.pentaho.org/libformula/
*
* (C) Copyright 2006-2008, 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.]
*
*
* ------------
* IsEvenFunction.java
* ------------
*/
package org.pentaho.reporting.libraries.formula.function.information;
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.TypeRegistry;
import org.pentaho.reporting.libraries.formula.typing.coretypes.LogicalType;
/**
* This function retruns true if the given value is an even number.
*
* @author Cedric Pronzato
*
*/
public class IsEvenFunction implements Function
{
private static final TypeValuePair RETURN_TRUE = new TypeValuePair(
LogicalType.TYPE, Boolean.TRUE);
private static final TypeValuePair RETURN_FALSE = new TypeValuePair(
LogicalType.TYPE, Boolean.FALSE);
private static final long serialVersionUID = 3298591139016352997L;
public IsEvenFunction()
{
}
public TypeValuePair evaluate(final FormulaContext context,
final 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 value = parameters.getValue(0);
final TypeRegistry typeRegistry = context.getTypeRegistry();
final Number number = typeRegistry.convertToNumber(type1, value);
if (number == null)
{
throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
}
int intValue = number.intValue();
if (intValue < 0)
{
intValue *= -1;
}
if (intValue % 2 == 0)
{
return RETURN_TRUE;
}
return RETURN_FALSE;
}
public String getCanonicalName()
{
return "ISEVEN";
}
}