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Java > Open Source Codes > com > db4o > foundation > Iterator4Impl


1 /* Copyright (C) 2004 - 2006 db4objects Inc. http://www.db4o.com
2
3 This file is part of the db4o open source object database.
4
5 db4o is free software; you can redistribute it and/or modify it under
6 the terms of version 2 of the GNU General Public License as published
7 by the Free Software Foundation and as clarified by db4objects' GPL
8 interpretation policy, available at
9 http://www.db4o.com/about/company/legalpolicies/gplinterpretation/
10 Alternatively you can write to db4objects, Inc., 1900 S Norfolk Street,
11 Suite 350, San Mateo, CA 94403, USA.
12
13 db4o is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
17
18 You should have received a copy of the GNU General Public License along
19 with this program; if not, write to the Free Software Foundation, Inc.,
20 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
21 package com.db4o.foundation;
22
23
24 /**
25  * @exclude
26  */
27 public class Iterator4Impl implements Iterator4 {
28     
29     public static final Iterator4 EMPTY = new Iterator4Impl(null);
30     
31     private List4 _first;
32     private List4 _next;
33     
34     private Object JavaDoc _current;
35
36     public Iterator4Impl(List4 first){
37         _first = first;
38         _next = first;
39         
40         _current = Iterators.NO_ELEMENT;
41     }
42
43     public boolean moveNext() {
44         if (_next == null) {
45             _current = Iterators.NO_ELEMENT;
46             return false;
47         }
48         _current = _next._element;
49         _next = _next._next;
50         return true;
51     }
52
53     public Object JavaDoc current(){
54         if (Iterators.NO_ELEMENT == _current) {
55             throw new IllegalStateException JavaDoc();
56         }
57         return _current;
58     }
59     
60     public void reset() {
61         _next = _first;
62         _current = Iterators.NO_ELEMENT;
63     }
64 }
65
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