01: /**
02: * ========================================
03: * JFreeReport : a free Java report library
04: * ========================================
05: *
06: * Project Info: http://reporting.pentaho.org/
07: *
08: * (C) Copyright 2000-2007, by Object Refinery Limited, Pentaho Corporation and Contributors.
09: *
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: IsEmptyExpression.java 3525 2007-10-16 11:43:48Z tmorgner $
27: * ------------
28: * (C) Copyright 2000-2005, by Object Refinery Limited.
29: * (C) Copyright 2005-2007, by Pentaho Corporation.
30: */package org.jfree.report.expressions.sys;
31:
32: import org.jfree.report.DataSourceException;
33: import org.jfree.report.expressions.AbstractExpression;
34:
35: /**
36: * Creation-Date: 27.01.2006, 20:42:19
37: *
38: * @author Thomas Morgner
39: */
40: public class IsEmptyExpression extends AbstractExpression {
41: private Object value;
42:
43: public IsEmptyExpression() {
44: }
45:
46: public Object getValue() {
47: return value;
48: }
49:
50: public void setValue(final Object value) {
51: this .value = value;
52: }
53:
54: /**
55: * Return the current expression value. <P> The value depends (obviously) on
56: * the expression implementation.
57: *
58: * @return the value of the function.
59: */
60: public Object computeValue() throws DataSourceException {
61: if (value == null) {
62: return Boolean.TRUE;
63: }
64: if (value instanceof String) {
65: final String s = (String) value;
66: if (s.trim().length() == 0) {
67: return Boolean.TRUE;
68: }
69: return Boolean.FALSE;
70: }
71: if (value instanceof Number) {
72: final Number n = (Number) value;
73: if (n.intValue() == 0) {
74: return Boolean.TRUE;
75: }
76: return Boolean.FALSE;
77: }
78: return Boolean.FALSE;
79: }
80: }
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