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Java > Open Source Codes > org > xquark > extractor > algebra > UnOpIsNull


1 /*
2  * This file belongs to the XQuark distribution.
3  * Copyright (C) 2003 Universite de Versailles Saint-Quentin.
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2.1 of the License, or (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307.
18  * You can also get it at http://www.gnu.org/licenses/lgpl.html
19  *
20  * For more information on this software, see http://www.xquark.org.
21  */
22
23 package org.xquark.extractor.algebra;
24
25 import org.xquark.extractor.common.SqlWrapperException;
26 import org.xquark.extractor.sql.SqlExpression;
27
28 public final class UnOpIsNull extends UnaryAtomicOp
29 {
30
31     private static final String JavaDoc RCSRevision = "$Revision: 1.3 $";
32     private static final String JavaDoc RCSName = "$Name: $";
33
34
35     private boolean _notNull ;
36
37     public UnOpIsNull(Expression operand )
38     {
39         super ( operand ) ;
40         setNot ( false ) ;
41     }
42     public UnOpIsNull(Expression operand , boolean notNull)
43     {
44         super ( operand ) ;
45         setNot ( notNull ) ;
46     }
47
48     public void setNot ( boolean notNull)
49     {
50         _notNull = notNull ;
51     }
52
53     public boolean getNot()
54     {
55         return _notNull ;
56     }
57
58     public SqlExpression accept (GenSqlVisitor visitor) throws SqlWrapperException
59     {
60         return visitor.visit(this);
61     }
62
63     public void accept (AlgebraVisitor visitor) throws SqlWrapperException
64     {
65         visitor.visit(this);
66     }
67     
68     /**
69      * @see Expression#deepEquals(Object)
70      */
71     public boolean deepEquals(Object JavaDoc o)
72     {
73         if (o instanceof UnOpIsNull)
74         {
75             UnOpIsNull cast = (UnOpIsNull)o;
76             return _notNull == cast.getNot() && super.deepEquals(o);
77         }
78         return false;
79     }
80 }
81
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