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: HasChangedFunction.java 3521 2007-10-16 10:55:14Z tmorgner $ 028 * ------------ 029 * (C) Copyright 2006-2007, by Pentaho Corporation. 030 */ 031 032 package org.jfree.formula.function.information; 033 034 import org.jfree.formula.function.Function; 035 import org.jfree.formula.function.ParameterCallback; 036 import org.jfree.formula.lvalues.TypeValuePair; 037 import org.jfree.formula.FormulaContext; 038 import org.jfree.formula.EvaluationException; 039 import org.jfree.formula.typing.coretypes.LogicalType; 040 041 /** 042 * Creation-Date: 24.11.2006, 13:02:41 043 * 044 * @author Thomas Morgner 045 */ 046 public class HasChangedFunction implements Function 047 { 048 private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE); 049 private static final TypeValuePair RETURN_TRUE = new TypeValuePair(LogicalType.TYPE, Boolean.TRUE); 050 051 public HasChangedFunction() 052 { 053 } 054 055 public String getCanonicalName() 056 { 057 return "HASCHANGED"; 058 } 059 060 public TypeValuePair evaluate(final FormulaContext context, 061 final ParameterCallback parameters) 062 throws EvaluationException 063 { 064 // we expect strings and will check, whether the reference for theses 065 // strings is dirty. 066 067 final int parCount = parameters.getParameterCount(); 068 for (int i = 0; i < parCount; i++) 069 { 070 final Object value = parameters.getValue(i); 071 if (value == null) 072 { 073 continue; 074 } 075 076 if (context.isReferenceDirty(value)) 077 { 078 return RETURN_TRUE; 079 } 080 } 081 return RETURN_FALSE; 082 } 083 }