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Java > Open Source Codes > org > fjank > jcache > NullObject


1 /* Open Source Java Caching Service
2 * Copyright (C) 2002 Frank Karlstrøm
3 * This library is free software; you can redistribute it and/or
4 * modify it under the terms of the GNU Lesser General Public
5 * License as published by the Free Software Foundation; either
6 * version 2.1 of the License, or (at your option) any later version.
7 *
8 * This library is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * Lesser General Public License for more details.
12 *
13 * You should have received a copy of the GNU Lesser General Public
14 * License along with this library; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
16 *
17 * The author can be contacted by email: fjankk@users.sourceforge.net
18 */
19 package org.fjank.jcache;
20
21 /**An object which can be used instead of null.
22  * @author Frank Karlstrøm
23  *
24  */
25 public final class NullObject {
26     private static NullObject _singleton;
27     private NullObject() {}
28     public static synchronized NullObject getInstance() {
29         if(_singleton==null) {
30             _singleton=new NullObject();
31         }
32         return _singleton;
33     }
34 }
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