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Java > Open Source Codes > org > lateralnz > common > util > ObjRefUtils


1 /* ====================================================================
2  * The LateralNZ Software License, Version 1.0
3  *
4  * Copyright (c) 2003 LateralNZ. All rights reserved.
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6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
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10  * 1. Redistributions of source code must retain the above copyright
11  * notice, this list of conditions and the following disclaimer.
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13  * 2. Redistributions in binary form must reproduce the above copyright
14  * notice, this list of conditions and the following disclaimer in
15  * the documentation and/or other materials provided with the
16  * distribution.
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18  * 3. The end-user documentation included with the redistribution,
19  * if any, must include the following acknowledgment:
20  * "This product includes software developed by
21  * LateralNZ (http://www.lateralnz.org/) and other third parties."
22  * Alternately, this acknowledgment may appear in the software itself,
23  * if and wherever such third-party acknowledgments normally appear.
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25  * 4. The names "LateralNZ" must not be used to endorse or promote
26  * products derived from this software without prior written
27  * permission. For written permission, please
28  * contact oss@lateralnz.org.
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30  * 5. Products derived from this software may not be called "Panther",
31  * or "Lateral" or "LateralNZ", nor may "PANTHER" or "LATERAL" or
32  * "LATERALNZ" appear in their name, without prior written
33  * permission of LateralNZ.
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35  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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49  * This software consists of voluntary contributions made by many
50  * individuals on behalf of LateralNZ. For more
51  * information on Lateral, please see http://www.lateralnz.com/ or
52  * http://www.lateralnz.org
53  *
54  */
55 package org.lateralnz.common.util;
56
57 import java.util.ArrayList JavaDoc;
58 import java.util.HashMap JavaDoc;
59
60 /**
61  * a way to ensure that certain singletons and other objects which
62  * should not be garbage collected, are not. This runs as a sleeping
63  * thread, and stores objects in a list -- they can never be retrieved
64  * since this should not be used as a retrieval mechanism
65  *
66  * @author J R Briggs
67  */
68 public final class ObjRefUtils extends Thread JavaDoc {
69   private static ObjRefUtils obj = null;
70
71   public ArrayList JavaDoc objects = new ArrayList JavaDoc();
72   public HashMap JavaDoc namedobjects = new HashMap JavaDoc();
73   boolean running = true;
74
75   private ObjRefUtils() {
76   }
77
78  /**
79   * get the singleton instance of this class
80   */
81   public static ObjRefUtils getInstance() {
82     if (obj == null) {
83       synchronized (ObjRefUtils.class) {
84         if (obj == null) {
85           obj = new ObjRefUtils();
86         }
87       }
88     }
89
90     return obj;
91   }
92
93  /**
94   * sleep forever
95   */
96   public void run() {
97     while (running) {
98       try { Thread.sleep(Long.MAX_VALUE); } catch (InterruptedException JavaDoc ie) { }
99     }
100   }
101
102  /**
103   * add an object to be remembered
104   */
105   public void add(Object JavaDoc o) {
106     objects.add(o);
107   }
108   
109   public Object JavaDoc get(String JavaDoc name) {
110     return namedobjects.get(name);
111   }
112   
113   public void set(String JavaDoc name, Object JavaDoc obj) {
114     namedobjects.put(name, obj);
115   }
116 }
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