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Java > Open Source Codes > org > apache > tomcat > util > threads > Reaper


1 /*
2  * Copyright 1999-2004 The Apache Software Foundation
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 package org.apache.tomcat.util.threads;
18
19
20 /**
21  * The reaper is a background thread with which ticks every minute
22  * and calls registered objects to allow reaping of old session
23  * data.
24  *
25  * @author James Duncan Davidson [duncan@eng.sun.com]
26  * @author Costin Manolache
27  */
28 public class Reaper extends Thread JavaDoc {
29     
30     
31     private static org.apache.commons.logging.Log log=
32         org.apache.commons.logging.LogFactory.getLog(Reaper.class );
33     
34     private boolean daemon = false;
35
36     public Reaper() {
37         if (daemon)
38             this.setDaemon(true);
39         this.setName("TomcatReaper");
40     }
41
42     public Reaper(String JavaDoc name) {
43         if (daemon)
44             this.setDaemon(true);
45         this.setName(name);
46     }
47
48     private long interval = 1000 * 60; //ms
49
50     // XXX TODO Allow per/callback interval, find next, etc
51 // Right now the "interval" is used for all callbacks
52 // and it represent a sleep between runs.
53
54     ThreadPoolRunnable cbacks[] = new ThreadPoolRunnable[30]; // XXX max
55 Object JavaDoc tdata[][] = new Object JavaDoc[30][]; // XXX max
56 int count = 0;
57
58     /** Adding and removing callbacks is synchronized
59      */
60     Object JavaDoc lock = new Object JavaDoc();
61     static boolean running = true;
62
63     // XXX Should be called 'interval' not defaultInterval
64
65     public void setDefaultInterval(long t) {
66         interval = t;
67     }
68
69     public long getDefaultIntervale() {
70         return interval;
71     }
72
73     public int addCallback(ThreadPoolRunnable c, int interval) {
74         synchronized (lock) {
75             cbacks[count] = c;
76             count++;
77             return count - 1;
78         }
79     }
80
81     public void removeCallback(int idx) {
82         synchronized (lock) {
83             count--;
84             cbacks[idx] = cbacks[count];
85             cbacks[count] = null;
86         }
87     }
88
89     public void startReaper() {
90         running = true;
91         this.start();
92     }
93
94     public synchronized void stopReaper() {
95         running = false;
96         if (log.isDebugEnabled())
97             log.debug("Stop reaper ");
98         this.interrupt(); // notify() doesn't stop sleep
99 }
100
101     public void run() {
102         while (running) {
103             if (!running)
104                 break;
105             try {
106                 Thread.sleep(interval);
107             } catch (InterruptedException JavaDoc ie) {
108                 // sometimes will happen
109 }
110
111             if (!running)
112                 break;
113             for (int i = 0; i < count; i++) {
114                 ThreadPoolRunnable callB = cbacks[i];
115                 // it may be null if a callback is removed.
116 // I think the code is correct
117 if (callB != null) {
118                     callB.runIt(tdata[i]);
119                 }
120                 if (!running)
121                     break;
122             }
123         }
124     }
125 }
126
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