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Java > Open Source Codes > test > dbc > stack > StackImpl


1 /*
2 * JBoss, Home of Professional Open Source
3 * Copyright 2005, JBoss Inc., and individual contributors as indicated
4 * by the @authors tag. See the copyright.txt in the distribution for a
5 * full listing of individual contributors.
6 *
7 * This is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU Lesser General Public License as
9 * published by the Free Software Foundation; either version 2.1 of
10 * the License, or (at your option) any later version.
11 *
12 * This software is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this software; if not, write to the Free
19 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
21 */
22 package test.dbc.stack;
23
24 import java.util.LinkedList JavaDoc;
25
26 /**
27  *
28  * @author <a HREF="mailto:kabir.khan@jboss.org">Kabir Khan </a>
29  * @version $Revision: 37406 $
30  */
31 public class StackImpl implements Stack
32 {
33    private final LinkedList JavaDoc elements = new LinkedList JavaDoc();
34
35    public void push(Object JavaDoc o)
36    {
37       elements.add(o);
38    }
39
40    public Object JavaDoc pop()
41    {
42       //For this we need $old functionality
43 //* @@org.jboss.aspects.dbc.PostCond ({"$tgt.top() == $rtn"})
44 final Object JavaDoc popped = top();
45       elements.removeLast();
46       return popped;
47    }
48
49    public Object JavaDoc top()
50    {
51       if (elements.size() == 0)
52       {
53          return null;
54       }
55       return elements.getLast();
56    }
57
58    public boolean isEmpty()
59    {
60       return elements.size() == 0;
61    }
62 }
63
64
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