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Java > Open Source Codes > com > db4o > nativequery > expr > NotExpression


1 /* Copyright (C) 2004 - 2006 db4objects Inc. http://www.db4o.com
2
3 This file is part of the db4o open source object database.
4
5 db4o is free software; you can redistribute it and/or modify it under
6 the terms of version 2 of the GNU General Public License as published
7 by the Free Software Foundation and as clarified by db4objects' GPL
8 interpretation policy, available at
9 http://www.db4o.com/about/company/legalpolicies/gplinterpretation/
10 Alternatively you can write to db4objects, Inc., 1900 S Norfolk Street,
11 Suite 350, San Mateo, CA 94403, USA.
12
13 db4o is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
17
18 You should have received a copy of the GNU General Public License along
19 with this program; if not, write to the Free Software Foundation, Inc.,
20 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
21 package com.db4o.nativequery.expr;
22
23
24 public class NotExpression implements Expression {
25     private Expression _expr;
26
27     public NotExpression(Expression expr) {
28         this._expr = expr;
29     }
30     
31     public String JavaDoc toString() {
32         return "!("+_expr+")";
33     }
34
35     public Expression expr() {
36         return _expr;
37     }
38     
39     public boolean equals(Object JavaDoc other) {
40         if (this == other) {
41             return true;
42         }
43         if (other == null || getClass() != other.getClass()) {
44             return false;
45         }
46         NotExpression casted = (NotExpression) other;
47         return _expr.equals(casted._expr);
48     }
49     
50     public int hashCode() {
51         return -_expr.hashCode();
52     }
53
54     public void accept(ExpressionVisitor visitor) {
55         visitor.visit(this);
56     }
57 }
58
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