/**
* =========================================
* 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: WeekDayFunction.java,v 1.1 2007/05/20 21:47:52 mimil Exp $
* ------------
* (C) Copyright 2006-2007, by Pentaho Corporation.
*/
package org.jfree.formula.function.datetime;
import java.util.Calendar;
import java.util.Date;
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.TypeRegistry;
import org.jfree.formula.typing.coretypes.NumberType;
import org.jfree.formula.util.DateUtil;
/**
* This function extracts the day of week from a date. <p/> The returned value
* depends of the Type passed as second argument using the following table:<br/>
* <TABLE>
* <TR>
* <TH>Day of Week</TH>
* <TH>Type=1 Result</TH>
* <TH>Type=2 Result</TH>
* <TH>Type=3 Result</TH>
* </TR>
* <TR>
* <TD>Sunday</TD>
* <TD> 1</TD>
* <TD> 7</TD>
* <TD> 6</TD>
* </TR>
* <TR>
* <TD>Monday</TD>
* <TD> 2</TD>
* <TD> 1</TD>
* <TD> 0</TD>
* </TR>
* <TR>
* <TD>Tuesday</TD>
* <TD> 3</TD>
* <TD> 2</TD>
* <TD> 1</TD>
* </TR>
* <TR>
* <TD>Wednesday</TD>
* <TD> 4</TD>
* <TD> 3</TD>
* <TD> 2</TD>
* </TR>
* <TR>
* <TD>Thursday</TD>
* <TD> 5</TD>
* <TD> 4</TD>
* <TD> 3</TD>
* </TR>
* <TR>
* <TD>Friday</TD>
* <TD> 6</TD>
* <TD> 5</TD>
* <TD> 4</TD>
* </TR>
* <TR>
* <TD>Saturday</TD>
* <TD> 7</TD>
* <TD> 6</TD>
* <TD> 5</TD>
* </TR>
* </TABLE>
*
* @author Cedric Pronzato
*/
public class WeekDayFunction implements Function
{
public WeekDayFunction()
{
}
public String getCanonicalName()
{
return "WEEKDAY";
}
public TypeValuePair evaluate(final FormulaContext context,
final ParameterCallback parameters) throws EvaluationException
{
if (parameters.getParameterCount() > 2)
{
throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
}
final TypeRegistry typeRegistry = context.getTypeRegistry();
final Date d = typeRegistry.convertToDate(parameters.getType(0), parameters
.getValue(0));
int type = 1; // default is Type 1
if (parameters.getParameterCount() == 2)
{
final Number n = typeRegistry.convertToNumber(parameters.getType(1),
parameters.getValue(1));
if (n == null)
{
throw new EvaluationException(
LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
}
type = n.intValue();
if (type < 1 || type > 3)
{
throw new EvaluationException(
LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
}
}
if (d == null)
{
throw new EvaluationException(
LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
}
final Calendar gc = DateUtil.createCalendar(d, context
.getLocalizationContext());
int dayOfWeek = gc.get(Calendar.DAY_OF_WEEK);
// in java Sunday = 1 (= Type 1 of openformula)
return new TypeValuePair(NumberType.GENERIC_NUMBER, new Integer(
convertType(dayOfWeek, type)));
}
public int convertType(int currentDayOfWeek, int type)
{
if (type == 1)
{
return currentDayOfWeek;
}
else if (type == 2)
{
final int i = ((currentDayOfWeek + 6) % 8);
if(i == 7)
{
return i;
}
else
{
return i + 1;
}
}
else
{
return (currentDayOfWeek + 5) % 7;
}
}
}