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Java > Open Source Codes > com > caucho > quercus > program > WhileStatement


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.program;
31
32 import com.caucho.quercus.Location;
33 import com.caucho.quercus.env.BreakValue;
34 import com.caucho.quercus.env.ContinueValue;
35 import com.caucho.quercus.env.Env;
36 import com.caucho.quercus.env.Value;
37 import com.caucho.quercus.expr.Expr;
38
39 /**
40  * Represents a while statement.
41  */
42 public class WhileStatement extends Statement {
43   protected final Expr _test;
44   protected final Statement _block;
45
46   public WhileStatement(Location location, Expr test, Statement block)
47   {
48     super(location);
49
50     _test = test;
51     _block = block;
52   }
53
54   public Value execute(Env env)
55   {
56     try {
57       while (_test.evalBoolean(env)) {
58         env.checkTimeout();
59
60         Value value = _block.execute(env);
61
62         if (value == null) {
63         }
64         else if (value == BreakValue.BREAK)
65           return null;
66         else if (value == ContinueValue.CONTINUE) {
67         }
68         else
69           return value;
70       }
71     }
72     catch (RuntimeException JavaDoc e) {
73       rethrow(e, RuntimeException JavaDoc.class);
74     }
75
76     return null;
77   }
78 }
79
80
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