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Java > Open Source Codes > SOFA > Component > ThreadIDRegistryImpl


1 /* $Id: ThreadIDRegistryImpl.java,v 1.1.1.1 2003/02/11 16:19:40 bures Exp $ */
2 package SOFA.Component;
3
4 /** Implementation of the thread registry.
5   *
6   */
7 public class ThreadIDRegistryImpl implements ThreadIDRegistry {
8   protected java.util.Hashtable JavaDoc threadIds;
9   protected java.util.Hashtable JavaDoc insideThreads;
10
11   /// SOFAnode name
12 protected String JavaDoc nodeName;
13
14   /// lock for testing inUpdate variable
15 private SOFA.Util.Lock lock;
16   private boolean inUpdate;
17
18   // wait while no thread is in component
19 private Waiting updateWt;
20   // incomming threads wait for update end
21 private Waiting thrWt;
22   
23   
24
25   public ThreadIDRegistryImpl(String JavaDoc _nodeName) {
26     threadIds = new java.util.Hashtable JavaDoc();
27     insideThreads = new java.util.Hashtable JavaDoc();
28     nodeName = _nodeName;
29     lock = new SOFA.Util.Lock(false);
30     inUpdate = false;
31     updateWt = new Waiting();
32     thrWt = new Waiting();
33   }
34
35   public void setInUpdate(boolean upd) {
36     if (upd) {
37       lock.lock();
38       inUpdate = true;
39       lock.unlock();
40       while (! insideThreads.isEmpty()) {
41         try {
42           updateWt.waitForSignal();
43         } catch (InterruptedException JavaDoc e) { }
44       }
45     } else { //unset inUpdate
46 lock.lock();
47       inUpdate = false;
48       lock.unlock();
49       thrWt.signalAll();
50     }
51   }
52
53   public String JavaDoc threadInCall(java.lang.String JavaDoc thr_id) {
54     lock.lock();
55     while (inUpdate) {
56       lock.unlock();
57       try {
58         thrWt.waitForSignal();
59       } catch (InterruptedException JavaDoc e) {}
60       lock.lock();
61     }
62     lock.unlock();
63     if (thr_id == null)
64       thr_id = generateThreadId();
65     threadIds.put(Thread.currentThread(), thr_id);
66     if (! insideThreads.containsKey(thr_id)) {
67       insideThreads.put(thr_id, new Counter());
68     } else {
69       ((Counter) insideThreads.get(thr_id)).inc();
70     }
71     return thr_id;
72   }
73
74   public String JavaDoc threadOutReturn(java.lang.String JavaDoc thr_id) {
75     if (((Counter)insideThreads.get(thr_id)).dec()==0) {
76       insideThreads.remove(thr_id);
77     }
78     updateWt.signal();
79     return thr_id;
80   }
81
82   public String JavaDoc threadOutCall() {
83     String JavaDoc id = (String JavaDoc) threadIds.get(Thread.currentThread());
84     if (id == null) {
85       id = generateThreadId();
86       threadIds.put(Thread.currentThread(), id);
87     }
88     return id;
89   }
90
91   public String JavaDoc threadInReturn(String JavaDoc thr_id) {
92     ; // do nothing
93 return thr_id;
94   }
95
96   /** Generates globaly unique thread identifier.
97     * @return thread identifier
98     */
99   private String JavaDoc generateThreadId() {
100     String JavaDoc ip = nodeName;
101     ip = ip + ":" + Long.toString(System.currentTimeMillis());
102     ip = ip + ":" + Thread.currentThread().getName();
103     return ip;
104   }
105 }
106
107 class Counter {
108   private long num;
109   
110   public Counter() {
111     num = 1;
112   }
113   
114   public long inc() {
115     return ++num;
116   }
117   
118   public long dec() {
119     if (num != 0)
120       num--;
121     return num;
122   }
123   
124   public long get() {
125     return num;
126   }
127 }
128
129 class Waiting {
130   public synchronized void waitForSignal() throws InterruptedException JavaDoc {
131     wait();
132   }
133
134   public synchronized void signal() {
135     notify();
136   }
137
138   public synchronized void signalAll() {
139     notifyAll();
140   }
141 }
142
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