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1
4 package com.tc.test;
5
6 import EDU.oswego.cs.dl.util.concurrent.CyclicBarrier;
7
8 public class BitChangeNotReflected extends TCTestCase {
9
10 private static final byte INITIAL = 0x01;
11 private static final int LOOP_COUNT = 50000;
12
13 public void testBitChangeNotReflected() throws Exception  {
14 BitData data = new BitData();
15 Object lock = new Object ();
16 CyclicBarrier barrier = new CyclicBarrier(2);
17 Thread t1 = new Changer(data, lock, barrier);
18 Thread t2 = new Reader(data, lock, barrier);
19 t1.start();
20 t2.start();
21 try {
22 t1.join();
23 t2.join();
24 } catch (InterruptedException e) {
25 throw new RuntimeException (e);
26 }
27 }
28
29 public static byte shiftRightRotate(byte f) {
30 byte f1 = (byte) (f >> 1);
31 return (byte) (f1 == 0x00 ? 0x80 : f1);
32 }
33
34 static class Changer extends Thread {
35
36 private final BitData data;
37 private final Object lock;
38 private final CyclicBarrier barrier;
39
40 public Changer(BitData data, Object lock, CyclicBarrier barrier) {
41 this.data = data;
42 this.lock = lock;
43 this.barrier = barrier;
44 }
45
46 public void run() {
47 try {
48 run2();
49 } catch (Exception e) {
50 throw new RuntimeException (e);
51 }
52 }
53
54 public void run2() throws Exception {
55 int count = LOOP_COUNT;
56 while (count-- > 0) {
57 barrier.barrier();
58 synchronized (lock) {
59 data.shiftRightRotate();
60 }
61 }
62 }
63
64 }
65
66 static class Reader extends Thread {
67
68 private final BitData data;
69 private final Object lock;
70 private final CyclicBarrier barrier;
71
72 public Reader(BitData data, Object lock, CyclicBarrier barrier) {
73 this.data = data;
74 this.lock = lock;
75 this.barrier = barrier;
76 }
77
78 public void run() {
79 try {
80 run2();
81 } catch (Exception e) {
82 throw new RuntimeException (e);
83 }
84 }
85
86 public void run2() throws Exception {
87 byte local = INITIAL;
88 int count = LOOP_COUNT;
89 while (count-- > 0) {
90 local = shiftRightRotate(local);
91 synchronized (lock) {
92 data.isEqual(local);
93 }
94 barrier.barrier();
95 }
96
97 }
98
99 }
100
101 static class BitData {
102 int i;
103 byte flag = INITIAL;
104
105 void shiftRightRotate() {
106 flag = BitChangeNotReflected.shiftRightRotate(flag);
107 }
108
109 boolean isEqual(byte f) {
110 return (flag == f);
111 }
112
113 byte getFlag() {
114 return flag;
115 }
116
117 }
118
119 }
120 |
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