/**
* =========================================
* 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.]
*
*
* ------------
* ExactFunction.java
* ------------
*/
package org.pentaho.reporting.libraries.formula.function.text;
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.TypeConversionException;
import org.pentaho.reporting.libraries.formula.typing.coretypes.LogicalType;
/**
* This function reports if two given text values are exactly equal using a case-sensitive comparison.
*
* @author Cedric Pronzato
*
*/
public class ExactFunction implements Function
{
private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE);
private static final TypeValuePair RETURN_TRUE = new TypeValuePair(LogicalType.TYPE, Boolean.TRUE);
private static final long serialVersionUID = -6303315343568906710L;
public ExactFunction()
{
}
public TypeValuePair evaluate(final FormulaContext context, final ParameterCallback parameters) throws EvaluationException
{
final int parameterCount = parameters.getParameterCount();
if (parameterCount != 2)
{
throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
}
final TypeRegistry typeRegistry = context.getTypeRegistry();
final Type textType1 = parameters.getType(0);
final Object textValue1 = parameters.getValue(0);
final Type textType2 = parameters.getType(1);
final Object textValue2 = parameters.getValue(1);
// Numerical comparisons ignore "trivial" differences that
// depend only on numeric precision of finite numbers.
// This fixes the common rounding errors, that are encountered when computing "((1/3) * 3)", which results
// in 0.99999 and not 1, as expected.
try
{
final Number number1 = typeRegistry.convertToNumber(textType1, textValue1);
final Number number2 = typeRegistry.convertToNumber(textType2, textValue2);
final double delta = Math.abs(Math.abs(number1.doubleValue()) - Math.abs(number2.doubleValue()));
if(delta < 0.00005)
{
return RETURN_TRUE;
}
return RETURN_FALSE;
}
catch(TypeConversionException tce)
{
// Ignore, try to compare them as strings ..
}
final String text1 = typeRegistry.convertToText(textType1, textValue1);
final String text2 = typeRegistry.convertToText(textType2, textValue2);
if(text1 == null || text2 == null)
{
throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
}
if (text1.equals(text2))
{
return RETURN_TRUE;
}
return RETURN_FALSE;
}
public String getCanonicalName()
{
return "EXACT";
}
}