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1: /** 2: * ========================================= 3: * LibFormula : a free Java formula library 4: * ========================================= 5: * 6: * Project Info: http://reporting.pentaho.org/libformula/ 7: * 8: * (C) Copyright 2006-2007, by Pentaho Corporation and Contributors. 9: * 10: * This library is free software; you can redistribute it and/or modify it under the terms 11: * of the GNU Lesser General Public License as published by the Free Software Foundation; 12: * either version 2.1 of the License, or (at your option) any later version. 13: * 14: * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 15: * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 16: * See the GNU Lesser General Public License for more details. 17: * 18: * You should have received a copy of the GNU Lesser General Public License along with this 19: * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, 20: * Boston, MA 02111-1307, USA. 21: * 22: * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 23: * in the United States and other countries.] 24: * 25: * 26: * ------------ 27: * $Id: ConcatOperator.java,v 1.8 2007/06/06 17:07:52 taqua Exp $ 28: * ------------ 29: * (C) Copyright 2006-2007, by Pentaho Corporation. 30: */ 31: package org.jfree.formula.operators; 32: 33: import org.jfree.formula.EvaluationException; 34: import org.jfree.formula.FormulaContext; 35: import org.jfree.formula.LibFormulaErrorValue; 36: import org.jfree.formula.lvalues.TypeValuePair; 37: import org.jfree.formula.typing.TypeRegistry; 38: import org.jfree.formula.typing.coretypes.TextType; 39: 40: /** 41: * Concats two strings operator. 42: * 43: * @author Thomas Morgner 44: */ 45: public class ConcatOperator implements InfixOperator 46: { 47: public ConcatOperator() 48: { 49: } 50: 51: public TypeValuePair evaluate(final FormulaContext context, 52: final TypeValuePair value1, 53: final TypeValuePair value2) 54: throws EvaluationException 55: { 56: final TypeRegistry typeRegistry = context.getTypeRegistry(); 57: 58: // Error or empty string, that's the question .. 59: final Object raw1 = value1.getValue(); 60: final Object raw2 = value2.getValue(); 61: if (raw1 == null || raw2 == null) 62: { 63: throw new EvaluationException(LibFormulaErrorValue.ERROR_NA_VALUE); 64: } 65: 66: final String text1 = typeRegistry.convertToText(value1.getType(), raw1); 67: final String text2 = typeRegistry.convertToText(value2.getType(), raw2); 68: if (text1 == null && text2 == null) 69: { 70: throw new EvaluationException 71: (LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE); 72: } 73: if (text1 == null) 74: { 75: return new TypeValuePair(TextType.TYPE, text2); 76: } 77: if (text2 == null) 78: { 79: return new TypeValuePair(TextType.TYPE, text1); 80: } 81: 82: return new TypeValuePair(TextType.TYPE, text1 + text2); 83: } 84: 85: public int getLevel() 86: { 87: return 300; 88: } 89: 90: 91: public String toString() 92: { 93: return "&"; 94: } 95: 96: public boolean isLeftOperation() 97: { 98: return true; 99: } 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: }