KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > com > caucho > loader > WeakDestroyListener


1 /*
2  * Copyright (c) 1998-2006 Caucho Technology -- all rights reserved
3  *
4  * This file is part of Resin(R) Open Source
5  *
6  * Each copy or derived work must preserve the copyright notice and this
7  * notice unmodified.
8  *
9  * Resin Open Source is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * Resin Open Source is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
17  * of NON-INFRINGEMENT. See the GNU General Public License for more
18  * details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with Resin Open Source; if not, write to the
22  * Free SoftwareFoundation, Inc.
23  * 59 Temple Place, Suite 330
24  * Boston, MA 02111-1307 USA
25  *
26  * @author Scott Ferguson
27  */
28
29 package com.caucho.loader;
30
31 import com.caucho.log.Log;
32 import com.caucho.util.L10N;
33
34 import java.lang.ref.WeakReference JavaDoc;
35 import java.lang.reflect.Method JavaDoc;
36 import java.util.logging.Level JavaDoc;
37 import java.util.logging.Logger JavaDoc;
38
39 /**
40  * Waits for the stop event and calls a @PreDestroy
41  */
42 public class WeakDestroyListener implements EnvironmentListener {
43   private static final L10N L = new L10N(WeakDestroyListener.class);
44   private static final Logger JavaDoc log = Log.open(WeakDestroyListener.class);
45
46   private Method JavaDoc _preDestroy;
47   private WeakReference JavaDoc<Object JavaDoc> _objRef;
48
49   /**
50    * Creates the new stop listener.
51    *
52    * @param resource the resource which needs closing
53    */
54   public WeakDestroyListener(Method JavaDoc preDestroy, Object JavaDoc obj)
55   {
56     _preDestroy = preDestroy;
57     
58     _objRef = new WeakReference JavaDoc<Object JavaDoc>(obj);
59   }
60
61   /**
62    * Handles the case where a class loader is activated.
63    */
64   public void environmentStart(EnvironmentClassLoader loader)
65   {
66   }
67   
68   /**
69    * Handles the case where a class loader is dropped.
70    */
71   public void environmentStop(EnvironmentClassLoader loader)
72   {
73     Object JavaDoc obj = _objRef.get();
74     if (obj == null)
75       return;
76     
77     try {
78       _preDestroy.invoke(obj, (Object JavaDoc []) null);
79     } catch (Throwable JavaDoc e) {
80       log.log(Level.WARNING, e.toString(), e);
81     }
82   }
83 }
84
85
Popular Tags