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Java > Open Source Codes > com > caucho > quercus > expr > NotExpr


1 /*
2  * Copyright (c) 1998-2006 Caucho Technology -- all rights reserved
3  *
4  * This file is part of Resin(R) Open Source
5  *
6  * Each copy or derived work must preserve the copyright notice and this
7  * notice unmodified.
8  *
9  * Resin Open Source is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * Resin Open Source is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
17  * of NON-INFRINGEMENT. See the GNU General Public License for more
18  * details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with Resin Open Source; if not, write to the
22  *
23  * Free Software Foundation, Inc.
24  * 59 Temple Place, Suite 330
25  * Boston, MA 02111-1307 USA
26  *
27  * @author Scott Ferguson
28  */

29
30 package com.caucho.quercus.expr;
31
32 import com.caucho.quercus.Location;
33 import com.caucho.quercus.env.BooleanValue;
34 import com.caucho.quercus.env.Env;
35 import com.caucho.quercus.env.Value;
36
37 /**
38  * Represents a PHP boolean negation
39  */

40 public class NotExpr extends UnaryExpr {
41   public NotExpr(Location location, Expr expr)
42   {
43     super(location, expr);
44   }
45
46   public NotExpr(Expr expr)
47   {
48     super(expr);
49   }
50
51   /**
52    * Return true as a boolean.
53    */

54   public boolean isBoolean()
55   {
56     return true;
57   }
58
59   /**
60    * Evaluates the equality as a boolean.
61    */

62   public Value eval(Env env)
63   {
64     return _expr.evalBoolean(env) ? BooleanValue.FALSE : BooleanValue.TRUE;
65   }
66
67   /**
68    * Evaluates the equality as a boolean.
69    */

70   public boolean evalBoolean(Env env)
71   {
72     return ! _expr.evalBoolean(env);
73   }
74
75   public String JavaDoc toString()
76   {
77     return "! " + _expr;
78   }
79 }
80
81
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