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Java > Open Source Codes > org > jgroups > protocols > PingWaiter


1 package org.jgroups.protocols;
2
3 import org.jgroups.stack.Protocol;
4 import org.jgroups.Event;
5 import org.apache.commons.logging.Log;
6 import org.apache.commons.logging.LogFactory;
7
8 import java.util.List JavaDoc;
9 import java.util.LinkedList JavaDoc;
10 import java.util.Vector JavaDoc;
11
12 /**
13  * Class that waits for n PingRsp'es, or m milliseconds to return the initial membership
14  * @author Bela Ban
15  * @version $Id: PingWaiter.java,v 1.6.2.1 2005/05/19 06:21:30 belaban Exp $
16  */
17 public class PingWaiter implements Runnable JavaDoc {
18     Thread JavaDoc t=null;
19     List JavaDoc rsps=new LinkedList JavaDoc();
20     long timeout=3000;
21     int num_rsps=3;
22     Protocol parent=null;
23     PingSender ping_sender;
24     protected final Log log=LogFactory.getLog(this.getClass());
25
26
27     public PingWaiter(long timeout, int num_rsps, Protocol parent, PingSender ping_sender) {
28         this.timeout=timeout;
29         this.num_rsps=num_rsps;
30         this.parent=parent;
31         this.ping_sender=ping_sender;
32     }
33
34
35     public synchronized void start() {
36         // ping_sender.start();
37 if(t == null || !t.isAlive()) {
38             t=new Thread JavaDoc(this, "PingWaiter");
39             t.setDaemon(true);
40             t.start();
41         }
42     }
43
44     public synchronized void stop() {
45         if(ping_sender != null)
46             ping_sender.stop();
47         if(t != null) {
48             // Thread tmp=t;
49 t=null;
50             // tmp.interrupt();
51 synchronized(rsps) {
52                 rsps.notifyAll();
53             }
54         }
55     }
56
57
58     public synchronized boolean isRunning() {
59         return t != null && t.isAlive();
60     }
61
62     public void addResponse(PingRsp rsp) {
63         if(rsp != null) {
64             synchronized(rsps) {
65                 if(rsps.contains(rsp))
66                     rsps.remove(rsp); // overwrite existing element
67 rsps.add(rsp);
68                 rsps.notifyAll();
69             }
70         }
71     }
72
73     public void clearResponses() {
74         synchronized(rsps) {
75             rsps.clear();
76             rsps.notifyAll();
77         }
78     }
79
80
81     public List JavaDoc getResponses() {
82         return rsps;
83     }
84
85
86
87     public void run() {
88         long start_time, time_to_wait;
89
90
91
92         synchronized(rsps) {
93             if(rsps.size() > 0) {
94                 if(log.isTraceEnabled())
95                     log.trace("clearing old responses: " + rsps);
96                 rsps.clear();
97             }
98             
99             ping_sender.start();
100
101             start_time=System.currentTimeMillis();
102             time_to_wait=timeout;
103
104             try {
105                 while(rsps.size() < num_rsps && time_to_wait > 0 && t != null && Thread.currentThread().equals(t)) {
106                     if(log.isTraceEnabled()) // +++ remove
107 log.trace("waiting for initial members: time_to_wait=" + time_to_wait +
108                                   ", got " + rsps.size() + " rsps");
109
110                     try {
111                         rsps.wait(time_to_wait);
112                     }
113                     catch(InterruptedException JavaDoc intex) {
114                         ;
115                     }
116                     catch(Exception JavaDoc e) {
117                         log.error("got an exception waiting for responses", e);
118                     }
119                     time_to_wait=timeout - (System.currentTimeMillis() - start_time);
120                 }
121                 if(log.isDebugEnabled())
122                     log.debug("initial mbrs are " + rsps);
123             }
124             finally {
125                 // 3. Send response
126 if(ping_sender != null)
127                     ping_sender.stop();
128
129                 if(parent != null)
130                     parent.passUp(new Event(Event.FIND_INITIAL_MBRS_OK, new Vector JavaDoc(rsps)));
131             }
132         }
133     }
134 }
135
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