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1 /*
2  * The Apache Software License, Version 1.1
3  *
4  * Copyright (c) 2002 The Apache Software Foundation. All rights
5  * reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  * notice, this list of conditions and the following disclaimer.
13  *
14  * 2. Redistributions in binary form must reproduce the above copyright
15  * notice, this list of conditions and the following disclaimer in
16  * the documentation and/or other materials provided with the
17  * distribution.
18  *
19  * 3. The end-user documentation included with the redistribution, if
20  * any, must include the following acknowlegement:
21  * "This product includes software developed by the
22  * Apache Software Foundation (http://www.apache.org/)."
23  * Alternately, this acknowlegement may appear in the software itself,
24  * if and wherever such third-party acknowlegements normally appear.
25  *
26  * 4. The names "Apache BSF", "Apache", and "Apache Software Foundation"
27  * must not be used to endorse or promote products derived from
28  * this software without prior written permission. For written
29  * permission, please contact apache@apache.org.
30  *
31  * 5. Products derived from this software may not be called "Apache"
32  * nor may "Apache" appear in their names without prior written
33  * permission of the Apache Group.
34  *
35  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
36  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
37  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
38  * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
39  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
41  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
42  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
43  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
44  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
45  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46  * SUCH DAMAGE.
47  * ====================================================================
48  *
49  * This software consists of voluntary contributions made by many individuals
50  * on behalf of the Apache Software Foundation and was originally created by
51  * Sanjiva Weerawarana and others at International Business Machines
52  * Corporation. For more information on the Apache Software Foundation,
53  * please see <http://www.apache.org/>.
54  */
55
56 package org.apache.bsf.util;
57
58 import java.util.Hashtable JavaDoc;
59
60 /**
61  * An <code>ScriptSymbolTable</code> object is used by a <code>CodeBuffer</code>
62  * object to implement nested scopes.
63  *
64  * @author Matthew J. Duftler
65  */
66 class ScriptSymbolTable extends Hashtable JavaDoc
67 {
68     private Hashtable JavaDoc parentTable;
69
70     ScriptSymbolTable(Hashtable JavaDoc parentTable)
71   {
72     this.parentTable = parentTable;
73   }
74   public synchronized Object JavaDoc get(Object JavaDoc key)
75   {
76     Object JavaDoc ret = super.get(key);
77
78     if (ret == null && parentTable != null)
79       ret = parentTable.get(key);
80
81     return ret;
82   }
83 }
84
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