Mercurial > hg > Applications > TightVNC_orginal

comparison src/main/java/ac/ryukyu/treevnc/MulticastQueue.java @ 3:e7ce2b2ffed8

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author Yu Taninari <you@cr.ie.u-ryukyu.ac.jp>
date Tue, 24 Jul 2012 15:46:36 +0900
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children b32668b8e83c
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2:dca3bd61b830 3:e7ce2b2ffed8
1 package ac.ryukyu.treevnc;
2
3 import java.util.concurrent.CountDownLatch;
4
5 public class MulticastQueue<T>
6 {
7
8 Node<T> tail;
9
10 public MulticastQueue()
11 {
12 tail = new Node<T>(null);
13 }
14
15 public synchronized void put(T item)
16 {
17 Node<T> next = new Node<T>(item);
18 tail.set(next);
19 tail = next;
20 }
21
22 public Client<T> newClient()
23 {
24 return new Client<T>(tail);
25 }
26
27 static class Client<T>
28 {
29 Node<T> node;
30
31 Client(Node<T> tail)
32 {
33 node = tail;
34 }
35
36 synchronized public T poll()
37 {
38 Node<T> next = null;
39 T item = null;
40 do {
41 try {
42 next = node.next();
43 }catch(InterruptedException _e){
44 continue;
45 }
46 // item = node.getItem();
47 item = next.getItem();
48 node = next;
49 } while ( item == null);
50 return item;
51 }
52 }
53
54 static class Node<T>
55 {
56 private T item;
57 private Node<T> next;
58 private CountDownLatch latch;
59
60 public Node(T item)
61 {
62 this.item = item;
63 this.next = null;
64 latch = new CountDownLatch(1);
65 }
66
67 synchronized public T getItem() {
68 return item;
69 }
70
71 public void set(Node<T> next)
72 {
73 this.next = next;
74 latch.countDown();
75 }
76
77 public Node<T> next() throws InterruptedException
78 {
79 latch.await();
80 return next;
81 }
82
83 synchronized public void clear() {
84 item = null;
85 }
86 }
87 }