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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: HasChangedFunction.java,v 1.5 2007/04/01 13:51:52 taqua Exp $ 28: * ------------ 29: * (C) Copyright 2006-2007, by Pentaho Corporation. 30: */ 31: 32: package org.jfree.formula.function.information; 33: 34: import org.jfree.formula.function.Function; 35: import org.jfree.formula.function.ParameterCallback; 36: import org.jfree.formula.lvalues.TypeValuePair; 37: import org.jfree.formula.FormulaContext; 38: import org.jfree.formula.EvaluationException; 39: import org.jfree.formula.typing.coretypes.LogicalType; 40: 41: /** 42: * Creation-Date: 24.11.2006, 13:02:41 43: * 44: * @author Thomas Morgner 45: */ 46: public class HasChangedFunction implements Function 47: { 48: private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE); 49: private static final TypeValuePair RETURN_TRUE = new TypeValuePair(LogicalType.TYPE, Boolean.TRUE); 50: 51: public HasChangedFunction() 52: { 53: } 54: 55: public String getCanonicalName() 56: { 57: return "HASCHANGED"; 58: } 59: 60: public TypeValuePair evaluate(FormulaContext context, 61: ParameterCallback parameters) 62: throws EvaluationException 63: { 64: // we expect strings and will check, whether the reference for theses 65: // strings is dirty. 66: 67: final int parCount = parameters.getParameterCount(); 68: for (int i = 0; i < parCount; i++) 69: { 70: final Object value = parameters.getValue(i); 71: if (value == null) 72: { 73: continue; 74: } 75: 76: if (context.isReferenceDirty(value)) 77: { 78: return RETURN_TRUE; 79: } 80: } 81: return RETURN_FALSE; 82: } 83: }