001 /**
002 * =========================================
003 * LibFormula : a free Java formula library
004 * =========================================
005 *
006 * Project Info: http://reporting.pentaho.org/libformula/
007 *
008 * (C) Copyright 2006-2007, by Pentaho Corporation and Contributors.
009 *
010 * This library is free software; you can redistribute it and/or modify it under the terms
011 * of the GNU Lesser General Public License as published by the Free Software Foundation;
012 * either version 2.1 of the License, or (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
015 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
016 * See the GNU Lesser General Public License for more details.
017 *
018 * You should have received a copy of the GNU Lesser General Public License along with this
019 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
020 * Boston, MA 02111-1307, USA.
021 *
022 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
023 * in the United States and other countries.]
024 *
025 *
026 * ------------
027 * $Id: TextFunction.java 3521 2007-10-16 10:55:14Z tmorgner $
028 * ------------
029 * (C) Copyright 2006-2007, by Pentaho Corporation.
030 */
031 package org.jfree.formula.function.text;
032
033 import org.jfree.formula.EvaluationException;
034 import org.jfree.formula.FormulaContext;
035 import org.jfree.formula.LibFormulaErrorValue;
036 import org.jfree.formula.function.Function;
037 import org.jfree.formula.function.ParameterCallback;
038 import org.jfree.formula.lvalues.TypeValuePair;
039 import org.jfree.formula.typing.Type;
040 import org.jfree.formula.typing.coretypes.TextType;
041
042 /**
043 * This function returns the given value as text.
044 *
045 * @author Cedric Pronzato
046 *
047 */
048 public class TextFunction implements Function
049 {
050 public TextFunction()
051 {
052 }
053
054 public TypeValuePair evaluate(final FormulaContext context, final ParameterCallback parameters) throws EvaluationException
055 {
056 final int parameterCount = parameters.getParameterCount();
057 if (parameterCount < 1)
058 {
059 throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
060 }
061 final Type type1 = parameters.getType(0);
062 final Object value1 = parameters.getValue(0);
063 final String result = context.getTypeRegistry().convertToText(type1, value1);
064
065 if(result == null)
066 {
067 throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
068 }
069
070 return new TypeValuePair(TextType.TYPE, result);
071 }
072
073 public String getCanonicalName()
074 {
075 return "TEXT";
076 }
077
078 }