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 }