NFunction.java

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;

public class NFunction implements Function {
  private static final TypeValuePair ZERO = new TypeValuePair( NumberType.GENERIC_NUMBER, BigDecimal.ZERO );

  public NFunction() {
  }

  public String getCanonicalName() {
    return "N";
  }

  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 );


    try {
      return new TypeValuePair( NumberType.GENERIC_NUMBER, context.getTypeRegistry().convertToNumber( type1, value1 ) );
    } catch ( EvaluationException e ) {
      return ZERO;
    }
  }
}