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: ConcatOperator.java 2887 2007-06-06 17:07:52Z taqua $ 028 * ------------ 029 * (C) Copyright 2006-2007, by Pentaho Corporation. 030 */ 031 package org.jfree.formula.operators; 032 033 import org.jfree.formula.EvaluationException; 034 import org.jfree.formula.FormulaContext; 035 import org.jfree.formula.LibFormulaErrorValue; 036 import org.jfree.formula.lvalues.TypeValuePair; 037 import org.jfree.formula.typing.TypeRegistry; 038 import org.jfree.formula.typing.coretypes.TextType; 039 040 /** 041 * Concats two strings operator. 042 * 043 * @author Thomas Morgner 044 */ 045 public class ConcatOperator implements InfixOperator 046 { 047 public ConcatOperator() 048 { 049 } 050 051 public TypeValuePair evaluate(final FormulaContext context, 052 final TypeValuePair value1, 053 final TypeValuePair value2) 054 throws EvaluationException 055 { 056 final TypeRegistry typeRegistry = context.getTypeRegistry(); 057 058 // Error or empty string, that's the question .. 059 final Object raw1 = value1.getValue(); 060 final Object raw2 = value2.getValue(); 061 if (raw1 == null || raw2 == null) 062 { 063 throw new EvaluationException(LibFormulaErrorValue.ERROR_NA_VALUE); 064 } 065 066 final String text1 = typeRegistry.convertToText(value1.getType(), raw1); 067 final String text2 = typeRegistry.convertToText(value2.getType(), raw2); 068 if (text1 == null && text2 == null) 069 { 070 throw new EvaluationException 071 (LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE); 072 } 073 if (text1 == null) 074 { 075 return new TypeValuePair(TextType.TYPE, text2); 076 } 077 if (text2 == null) 078 { 079 return new TypeValuePair(TextType.TYPE, text1); 080 } 081 082 return new TypeValuePair(TextType.TYPE, text1 + text2); 083 } 084 085 public int getLevel() 086 { 087 return 300; 088 } 089 090 091 public String toString() 092 { 093 return "&"; 094 } 095 096 public boolean isLeftOperation() 097 { 098 return true; 099 } 100 101 /** 102 * Defines, whether the operation is associative. For associative operations, 103 * the evaluation order does not matter, if the operation appears more than 104 * once in an expression, and therefore we can optimize them a lot better than 105 * non-associative operations (ie. merge constant parts and precompute them 106 * once). 107 * 108 * @return true, if the operation is associative, false otherwise 109 */ 110 public boolean isAssociative() 111 { 112 return false; 113 } 114 115 }