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: TrimFunction.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 text free of leading spaces.
044 * Removes all leading and trailing spaces and all extra spaces inside the text.
045 *
046 * @author Cedric Pronzato
047 * @see http://mercury.ccil.org/%7Ecowan/OF/textfuncs.html
048 */
049 public class TrimFunction implements Function
050 {
051 public TrimFunction()
052 {
053 }
054
055 public TypeValuePair evaluate(final FormulaContext context, final ParameterCallback parameters) throws EvaluationException
056 {
057 final int parameterCount = parameters.getParameterCount();
058 if (parameterCount < 1)
059 {
060 throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
061 }
062 final Type type1 = parameters.getType(0);
063 final Object value1 = parameters.getValue(0);
064 final String result = context.getTypeRegistry().convertToText(type1, value1);
065
066 if(result == null)
067 {
068 throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
069 }
070
071 // remove all unnecessary spaces ..
072 // we dont use regexps, because they are JDK 1.4, but this library is aimed
073 // for JDK 1.2.2
074
075 final char[] chars = result.toCharArray();
076 final StringBuffer b = new StringBuffer(chars.length);
077 boolean removeNextWs = true;
078
079 for (int i = 0; i < chars.length; i++)
080 {
081 final char c = chars[i];
082 if (Character.isWhitespace(c))
083 {
084 if (removeNextWs)
085 {
086 continue;
087 }
088 b.append(c);
089 removeNextWs = true;
090 continue;
091 }
092
093 b.append(c);
094 removeNextWs = false;
095 }
096
097 // now check whether the last char is a whitespace and remove that one
098 // if neccessary
099 final String trimmedResult;
100 if (removeNextWs)
101 {
102 trimmedResult = b.substring(0, b.length() - 1);
103 }
104 else
105 {
106 trimmedResult = b.toString();
107 }
108
109 return new TypeValuePair(TextType.TYPE, trimmedResult);
110 }
111
112 public String getCanonicalName()
113 {
114 return "TRIM";
115 }
116
117 }