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


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 a PHP required expression.
39  */
40 public class RequiredExpr extends Expr {
41   public static final RequiredExpr REQUIRED = new RequiredExpr(Location.UNKNOWN);
42
43   public RequiredExpr(Location location)
44   {
45     super(location);
46   }
47
48   public RequiredExpr()
49   {
50     super();
51   }
52
53   /**
54    * Evaluates the expression.
55    *
56    * @param env the calling environment.
57    *
58    * @return the expression value.
59    */
60   public Value eval(Env env)
61   {
62     env.warning("required argument missing");
63
64     return NullValue.NULL;
65   }
66
67   public String JavaDoc toString()
68   {
69     return "required";
70   }
71 }
72
73
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