/**
* =========================================
* 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: ChooseFunction.java,v 1.5 2007/04/10 14:10:41 taqua Exp $
* ------------
* (C) Copyright 2006-2007, by Pentaho Corporation.
*/
package org.jfree.formula.function.information;
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;
/**
* This function uses an index to return a value from a list of values.
* The first value index is 1, 2 for the second and so on.
*
* @author Cedric Pronzato
*/
public class ChooseFunction implements Function
{
public ChooseFunction()
{
}
public String getCanonicalName()
{
return "CHOOSE";
}
public TypeValuePair evaluate(final FormulaContext context,
final ParameterCallback parameters)
throws EvaluationException
{
if(parameters.getParameterCount() <= 2)
{
throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
}
final Type indexType = parameters.getType(0);
final Object indexValue = parameters.getValue(0);
final int index= context.getTypeRegistry().convertToNumber(indexType, indexValue).intValue();
if(index >= 1 && index < parameters.getParameterCount())
{
return new TypeValuePair(parameters.getType(index), parameters.getValue(index));
}
// else
throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
}
}