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Java > Open Source Codes > org > dom4j > util > SimpleSingleton


1 /*
2  * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
3  *
4  * This software is open source.
5  * See the bottom of this file for the licence.
6  */
7
8 package org.dom4j.util;
9
10 /**
11  * <p>
12  * <code>SimpleSingleton</code> is an implementation of the SingletonStrategy
13  * interface used to provide common factory access for the same object instance.
14  * This implementation will create a new instance from the class specified and
15  * will not create a new one unless it is reset.
16  * </p>
17  *
18  * @author <a HREF="mailto:ddlucas@users.sourceforge.net">David Lucas </a>
19  * @version $Revision: 1.3 $
20  */
21
22 public class SimpleSingleton implements SingletonStrategy {
23     private String JavaDoc singletonClassName = null;
24
25     private Object JavaDoc singletonInstance = null;
26
27     public SimpleSingleton() {
28     }
29
30     public Object JavaDoc instance() {
31         return singletonInstance;
32     }
33
34     public void reset() {
35         if (singletonClassName != null) {
36             Class JavaDoc clazz = null;
37             try {
38                 clazz = Thread.currentThread().getContextClassLoader().loadClass(
39                         singletonClassName);
40                 singletonInstance = clazz.newInstance();
41             } catch (Exception JavaDoc ignore) {
42                 try {
43                     clazz = Class.forName(singletonClassName);
44                     singletonInstance = clazz.newInstance();
45                 } catch (Exception JavaDoc ignore2) {
46                 }
47             }
48
49         }
50     }
51
52     public void setSingletonClassName(String JavaDoc singletonClassName) {
53         this.singletonClassName = singletonClassName;
54         reset();
55     }
56
57 }
58
59 /*
60  * Redistribution and use of this software and associated documentation
61  * ("Software"), with or without modification, are permitted provided that the
62  * following conditions are met:
63  *
64  * 1. Redistributions of source code must retain copyright statements and
65  * notices. Redistributions must also contain a copy of this document.
66  *
67  * 2. Redistributions in binary form must reproduce the above copyright notice,
68  * this list of conditions and the following disclaimer in the documentation
69  * and/or other materials provided with the distribution.
70  *
71  * 3. The name "DOM4J" must not be used to endorse or promote products derived
72  * from this Software without prior written permission of MetaStuff, Ltd. For
73  * written permission, please contact dom4j-info@metastuff.com.
74  *
75  * 4. Products derived from this Software may not be called "DOM4J" nor may
76  * "DOM4J" appear in their names without prior written permission of MetaStuff,
77  * Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
78  *
79  * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
80  *
81  * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND
82  * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
83  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
84  * ARE DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE
85  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
86  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
87  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
88  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
89  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
90  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
91  * POSSIBILITY OF SUCH DAMAGE.
92  *
93  * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
94  */
95
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