1   /**
2    * Copyright (c) 2000-2010 Liferay, Inc. All rights reserved.
3    *
4    * The contents of this file are subject to the terms of the Liferay Enterprise
5    * Subscription License ("License"). You may not use this file except in
6    * compliance with the License. You can obtain a copy of the License by
7    * contacting Liferay, Inc. See the License for the specific language governing
8    * permissions and limitations under the License, including but not limited to
9    * distribution rights of the Software.
10   *
11   *
12   *
13   */
14  
15  package com.liferay.portal.kernel.memory;
16  
17  import com.liferay.portal.kernel.util.GetterUtil;
18  import com.liferay.portal.kernel.util.PropsKeys;
19  import com.liferay.portal.kernel.util.PropsUtil;
20  
21  import java.lang.ref.Reference;
22  import java.lang.ref.ReferenceQueue;
23  
24  import java.util.Map;
25  import java.util.concurrent.ConcurrentHashMap;
26  
27  /**
28   * <a href="FinalizeManager.java.html"><b><i>View Source</i></b></a>
29   *
30   * @author Shuyang Zhou
31   */
32  public class FinalizeManager {
33  
34      public static final boolean THREAD_ENABLED = GetterUtil.getBoolean(
35          PropsUtil.get(PropsKeys.FINALIZE_MANAGER_THREAD_ENABLED));
36  
37      public static <T> Reference<T> register(
38          T realReference, FinalizeAction finalizeAction) {
39  
40          Reference<T> reference = new EqualityWeakReference<T>(
41              realReference, _referenceQueue);
42  
43          _referenceActionMap.put(reference, finalizeAction);
44  
45          if (!THREAD_ENABLED) {
46              _pollingCleanup();
47          }
48  
49          return reference;
50      }
51  
52      private static void _pollingCleanup() {
53          Reference<? extends Object> reference = null;
54  
55          while ((reference = _referenceQueue.poll()) != null) {
56              FinalizeAction finalizeAction = _referenceActionMap.remove(
57                  reference);
58  
59              finalizeAction.doFinalize();
60          }
61      }
62  
63      private static Map<Reference<?>, FinalizeAction> _referenceActionMap =
64          new ConcurrentHashMap<Reference<?>, FinalizeAction>();
65      private static ReferenceQueue<Object> _referenceQueue =
66          new ReferenceQueue<Object>();
67  
68      private static class FinalizeThread extends Thread {
69  
70          public FinalizeThread(String name) {
71              super(name);
72          }
73  
74          public void run() {
75              while (true) {
76                  try {
77                      Reference<? extends Object> reference =
78                          _referenceQueue.remove();
79  
80                      FinalizeAction finalizeAction =
81                          _referenceActionMap.remove(reference);
82  
83                      finalizeAction.doFinalize();
84                  }
85                  catch (InterruptedException ie) {
86                  }
87              }
88          }
89      }
90  
91      static {
92          if (THREAD_ENABLED) {
93              Thread thread = new FinalizeThread("Finalize Thread");
94  
95              thread.setDaemon(true);
96  
97              thread.start();
98          }
99      }
100 
101 }