1 //----------------------------------------------------------------------
2 //
3 // PerfectJPattern: "Design patterns are good but components are better!"
4 // NullRequest.java Copyright (c) 2009 Giovanni Azua Garcia
5 // bravegag@hotmail.com
6 //
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License
9 // as published by the Free Software Foundation; either version 3
10 // of the License, or (at your option) any later version.
11 //
12 // This program 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
15 // GNU General Public License for more details.
16 //
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, see <http://www.gnu.org/licenses/>.
19 //
20 //----------------------------------------------------------------------
21 package org.perfectjpattern.core.api.behavioral.chainofresponsibility;
22
23 import org.perfectjpattern.core.api.creational.singleton.ISingleton;
24
25 /**
26 * Null Object Pattern implementation of Chain of Responsibility
27 * Request Parameter.
28 * <br/><br/>
29 * <code>NullRequest</code> is a Singleton therefore it may not be directly
30 * instantiated, neither it may be extended.
31 *
32 * @author <a href="mailto:bravegag@hotmail.com">Giovanni Azua</a>
33 * @version $Revision: 1.0 $ $Date: Nov 6, 2007 5:35:36 PM $
34 */
35 public final
36 class NullRequest
37 implements ISingleton
38 {
39 //------------------------------------------------------------------------
40 // public
41 //------------------------------------------------------------------------
42 /**
43 * Returns Singleton instance of <code>NullRequest</code>.
44 *
45 * @return Singleton instance of <code>NullRequest</code>.
46 */
47 public static NullRequest
48 getInstance()
49 {
50 return INSTANCE;
51 }
52
53 //------------------------------------------------------------------------
54 // private
55 //------------------------------------------------------------------------
56 private
57 NullRequest()
58 {
59 // do nothing
60 }
61
62 //------------------------------------------------------------------------
63 // members
64 //------------------------------------------------------------------------
65 /**
66 * Singleton instance of <code>NullRequest</code>
67 */
68 private static final NullRequest INSTANCE = new NullRequest();
69 }