1 //******************************************************************************
2 //
3 // File: ItemGenerator.java
4 // Package: edu.rit.pj
5 // Unit: Class edu.rit.pj.ItemGenerator
6 //
7 // This Java source file is copyright (C) 2007 by Alan Kaminsky. All rights
8 // reserved. For further information, contact the author, Alan Kaminsky, at
9 // ark@cs.rit.edu.
10 //
11 // This Java source file is part of the Parallel Java Library ("PJ"). PJ is free
12 // software; you can redistribute it and/or modify it under the terms of the GNU
13 // General Public License as published by the Free Software Foundation; either
14 // version 3 of the License, or (at your option) any later version.
15 //
16 // PJ is distributed in the hope that it will be useful, but WITHOUT ANY
17 // WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
18 // A PARTICULAR PURPOSE. See the GNU General Public License for more details.
19 //
20 // Linking this library statically or dynamically with other modules is making a
21 // combined work based on this library. Thus, the terms and conditions of the GNU
22 // General Public License cover the whole combination.
23 //
24 // As a special exception, the copyright holders of this library give you
25 // permission to link this library with independent modules to produce an
26 // executable, regardless of the license terms of these independent modules, and
27 // to copy and distribute the resulting executable under terms of your choice,
28 // provided that you also meet, for each linked independent module, the terms
29 // and conditions of the license of that module. An independent module is a module
30 // which is not derived from or based on this library. If you modify this library,
31 // you may extend this exception to your version of the library, but you are not
32 // obligated to do so. If you do not wish to do so, delete this exception
33 // statement from your version.
34 //
35 // A copy of the GNU General Public License is provided in the file gpl.txt. You
36 // may also obtain a copy of the GNU General Public License on the World Wide
37 // Web at http://www.gnu.org/licenses/gpl.html.
38 //
39 //******************************************************************************
40 package edu.rit.pj;
41
42 /**
43 * Class ItemGenerator is the abstract base class for an object that generates
44 * items for a {@linkplain ParallelIteration}.
45 *
46 * @param <T> Data type of the items iterated over.
47 *
48 * @author Alan Kaminsky
49 * @version 04-Jun-2007
50 */
51 abstract class ItemGenerator<T> {
52
53 // Hidden data members.
54 // Current item sequence number for filling in the item holder.
55 int myCurrentSequenceNumber;
56
57 // Current iteration index for use by the ordered() construct.
58 int myOrderedIndex;
59
60 // True to break out of the parallel iteration.
61 boolean myBreak;
62
63 // Exported constructors.
64 /**
65 * Construct a new item generator.
66 */
67 public ItemGenerator() {
68 }
69
70 // Exported operations.
71 /**
72 * Return an item holder containing the next item to be processed plus
73 * associated information.
74 *
75 * @return Item holder, or null if no more items.
76 */
77 public abstract ItemHolder<T> nextItem();
78
79 }