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Java > Open Source Codes > org > xquark > mapper > util > Stack


1 /*
2  * This file belongs to the XQuark distribution.
3  * Copyright (C) 2003 Universite de Versailles Saint-Quentin.
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2.1 of the License, or (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307.
18  * You can also get it at http://www.gnu.org/licenses/lgpl.html
19  *
20  * For more information on this software, see http://www.xquark.org.
21  */
22
23 package org.xquark.mapper.util;
24
25
26 import java.util.ArrayList JavaDoc;
27
28 /** This class is a stack implementation backed by the JAVA2 ArrayList collection.
29  *
30  * <p> A new stack was created instead of using the standard one derived
31  * from the Vector class in order to use unsynchronized features.</p>
32  *
33  */
34
35 public class Stack extends ArrayList JavaDoc
36 {
37 private static final String JavaDoc RCSRevision = "$Revision: 1.1 $";
38 private static final String JavaDoc RCSName = "$Name: $";
39
40     public Object JavaDoc push(Object JavaDoc item)
41     {
42         add(item);
43         return item;
44     }
45
46     public Object JavaDoc pop()
47     {
48         if (size() > 0)
49             return remove(size()-1);
50         else
51             return null;
52     }
53
54     public Object JavaDoc top()
55     {
56         if (size() > 0)
57         return get(size()-1);
58         else
59         return null;
60     }
61
62     public boolean empty()
63     {
64         return (size() == 0);
65     }
66
67
68     public String JavaDoc toString()
69     {
70         StringBuffer JavaDoc dummy = new StringBuffer JavaDoc();
71         for(int i=0; i<size(); i++)
72         dummy.append("\n"+get(i));
73         return dummy.toString();
74     }
75 }
76
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