001 /** 002 * ======================================== 003 * JFreeReport : a free Java report library 004 * ======================================== 005 * 006 * Project Info: http://reporting.pentaho.org/ 007 * 008 * (C) Copyright 2000-2007, by Object Refinery Limited, 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 * $Id: IsNullExpression.java 2725 2007-04-01 18:49:29Z taqua $ 027 * ------------ 028 * (C) Copyright 2000-2005, by Object Refinery Limited. 029 * (C) Copyright 2005-2007, by Pentaho Corporation. 030 */ 031 package org.jfree.report.expressions.sys; 032 033 import org.jfree.report.DataSourceException; 034 import org.jfree.report.expressions.AbstractExpression; 035 036 /** 037 * Creation-Date: 27.01.2006, 20:42:19 038 * 039 * @author Thomas Morgner 040 */ 041 public class IsNullExpression extends AbstractExpression 042 { 043 private Object value; 044 045 public IsNullExpression() 046 { 047 } 048 049 public Object getValue() 050 { 051 return value; 052 } 053 054 public void setValue(final Object value) 055 { 056 this.value = value; 057 } 058 059 /** 060 * Return the current expression value. <P> The value depends (obviously) on 061 * the expression implementation. 062 * 063 * @return the value of the function. 064 */ 065 public Object computeValue() throws DataSourceException 066 { 067 if (value == null) 068 { 069 return Boolean.TRUE; 070 } 071 return Boolean.FALSE; 072 } 073 }