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1: /** 2: * ======================================== 3: * JFreeReport : a free Java report library 4: * ======================================== 5: * 6: * Project Info: http://reporting.pentaho.org/ 7: * 8: * (C) Copyright 2000-2007, by Object Refinery Limited, 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: * $Id: IsEmptyDataExpression.java 2725 2007-04-01 18:49:29Z taqua $ 27: * ------------ 28: * (C) Copyright 2000-2005, by Object Refinery Limited. 29: * (C) Copyright 2005-2007, by Pentaho Corporation. 30: */ 31: package org.jfree.report.expressions.sys; 32: 33: import org.jfree.report.DataSourceException; 34: import org.jfree.report.ReportData; 35: import org.jfree.report.expressions.AbstractExpression; 36: import org.jfree.report.expressions.ExpressionRuntime; 37: 38: /** 39: * Creation-Date: 31.01.2006, 18:55:09 40: * 41: * @author Thomas Morgner 42: */ 43: public class IsEmptyDataExpression extends AbstractExpression 44: { 45: public IsEmptyDataExpression() 46: { 47: } 48: 49: /** 50: * Return the current expression value. <P> The value depends (obviously) on 51: * the expression implementation. 52: * 53: * @return the value of the function. 54: */ 55: public Object computeValue() throws DataSourceException 56: { 57: 58: final ExpressionRuntime runtime = getRuntime(); 59: if (runtime == null) 60: { 61: return null; 62: } 63: 64: final ReportData data = runtime.getData(); 65: if (data == null) 66: { 67: return null; 68: } 69: synchronized(data) 70: { 71: if (data.getCursorPosition() > 0) 72: { 73: return Boolean.FALSE; 74: } 75: if (data.isAdvanceable() == false) 76: { 77: return Boolean.TRUE; 78: } 79: return Boolean.FALSE; 80: } 81: } 82: }