1 /***
2 * The contents of this file are subject to the Mozilla Public
3 * License Version 1.1 (the "License"); you may not use this file
4 * except in compliance with the License. You may obtain a copy of
5 * the License at http://www.mozilla.org/MPL/
6 *
7 * Software distributed under the License is distributed on an "AS
8 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
9 * implied. See the License for the specific language governing
10 * rights and limitations under the License.
11 *
12 * The Original Code is pow2toolkit library.
13 *
14 * The Initial Owner of the Original Code is
15 * Power Of Two S.R.L. (www.pow2.com)
16 *
17 * Portions created by Power Of Two S.R.L. are
18 * Copyright (C) Power Of Two S.R.L.
19 * All Rights Reserved.
20 *
21 * Contributor(s):
22 */
23
24 package com.pow2.dao;
25
26
27
28 /***
29 * Data access object class.
30 * <br>
31 * Extends AbstractDAO, and use the singleton
32 * design pattern to provide an unique object instance
33 * per vm.
34 *
35 * @author Luca Fossato
36 * @version $Id: DAO.java,v 1.1.1.1 2004/08/31 20:22:46 foxat Exp $
37 */
38 public class DAO extends AbstractDAO
39 {
40 /*** an handle to the unique DAO instance. */
41 private static DAO instance = null;
42
43
44 /***
45 * Protected default constructor.
46 * <br>
47 * Initialize the data access object properties,
48 * and load the selected JDBC Driver class.
49 */
50 protected DAO()
51 {
52 super();
53 }
54
55
56 /***
57 * Get the instance of DAO class.
58 *
59 * @return the instance of DAO class.
60 */
61 public static synchronized DAO instance()
62 {
63 if (instance == null) instance = new DAO();
64 return instance;
65 }
66 }
67