package org.pentaho.reporting.libraries.formula.function.information;
import java.math.BigDecimal;
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.ContextLookup;
import org.pentaho.reporting.libraries.formula.lvalues.LValue;
import org.pentaho.reporting.libraries.formula.lvalues.TypeValuePair;
import org.pentaho.reporting.libraries.formula.typing.Type;
import org.pentaho.reporting.libraries.formula.typing.TypeConversionException;
import org.pentaho.reporting.libraries.formula.typing.Sequence;
import org.pentaho.reporting.libraries.formula.typing.coretypes.NumberType;
import org.pentaho.reporting.libraries.formula.typing.sequence.AnySequence;
/**
* This function counts the number of blank cells in the Reference provided. A cell is blank if it cell is empty.
*
* @author Cedric Pronzato
*/
// todo: maybe use something else than sequence (use array instead because sequence allows the use of scalar)
public class CountBlankFunction implements Function
{
public CountBlankFunction()
{
}
public String getCanonicalName()
{
return "COUNTBLANK";
}
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);
}
int count = 0;
final Object value = parameters.getValue(0);
final Type type = parameters.getType(0);
final LValue raw = parameters.getRaw(0);
if (raw instanceof ContextLookup)
{
if (value != null)
{
try
{
final Sequence sequence = context.getTypeRegistry().convertToSequence(type, value);
while (sequence.hasNext())
{
final Object o = sequence.next();
if (o == null)
{
count++;
}
}
}
catch (EvaluationException e)
{
}
}
}
return new TypeValuePair(NumberType.GENERIC_NUMBER, new BigDecimal(count));
}
}