/*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This program 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.
*
* Copyright (c) 2006 - 2013 Pentaho Corporation and Contributors. All rights reserved.
*/
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.coretypes.TextType;
/**
* This function returns extracted text, given an original text, starting position, and length.
*
* @author Cedric Pronzato
*
*/
public class MidFunction implements Function
{
private static final long serialVersionUID = 4190365695032245709L;
public MidFunction()
{
}
public TypeValuePair evaluate(final FormulaContext context,
final ParameterCallback parameters) throws EvaluationException
{
final int parameterCount = parameters.getParameterCount();
if (parameterCount != 3)
{
throw EvaluationException.getInstance(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
}
final TypeRegistry typeRegistry = context.getTypeRegistry();
final Type textType = parameters.getType(0);
final Object textValue = parameters.getValue(0);
final Type startType = parameters.getType(1);
final Object startValue = parameters.getValue(1);
final Type lengthType = parameters.getType(2);
final Object lengthValue = parameters.getValue(2);
final String text = typeRegistry.convertToText(textType, textValue);
final Number start = typeRegistry.convertToNumber(startType, startValue);
final Number length = typeRegistry.convertToNumber(lengthType, lengthValue);
if(length.doubleValue() < 0 || start.doubleValue() < 1)
{
throw EvaluationException.getInstance(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
}
return new TypeValuePair(TextType.TYPE, process(text, start.intValue(), length.intValue()));
}
/**
* Computes the substring for the given text, using the 1-based start index and the given length.
*
* @param text
* @param start
* @param lengthValue
* @return
*/
public static String process(final String text, final int start, int lengthValue)
{
final int startValue = start -1;
if(startValue >= text.length() || startValue < 0)
{
return "";
}
if((lengthValue +startValue) > text.length())
{
lengthValue = text.length()-startValue;
}
return text.substring(startValue, startValue +lengthValue);
}
public String getCanonicalName()
{
return "MID";
}
}