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


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.Env;
34 import com.caucho.quercus.env.NullValue;
35 import com.caucho.quercus.env.Value;
36
37 /**
38  * Represents unsetting a PHP variable
39  */

40 public class UnsetVarExpr extends Expr {
41   protected final AbstractVarExpr _var;
42
43   public UnsetVarExpr(Location location, AbstractVarExpr var)
44   {
45     super(location);
46     _var = var;
47   }
48
49   public UnsetVarExpr(AbstractVarExpr var)
50   {
51     _var = var;
52   }
53
54   /**
55    * Evaluates the expression.
56    *
57    * @param env the calling environment.
58    *
59    * @return the expression value.
60    */

61   public Value eval(Env env)
62   {
63     _var.evalUnset(env);
64
65     return NullValue.NULL;
66   }
67
68   public int hashCode()
69   {
70     return _var.hashCode();
71   }
72
73   public boolean equals(Object JavaDoc o)
74   {
75     if (this == o)
76       return true;
77     else if (getClass() != o.getClass())
78       return false;
79
80     UnsetVarExpr expr = (UnsetVarExpr) o;
81
82     return _var == expr._var;
83   }
84
85   public String JavaDoc toString()
86   {
87     return "unset(" + _var + ")";
88   }
89 }
90
91
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