/[cvs]/jsr166/src/test/tck/SystemTest.java
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Contents of /jsr166/src/test/tck/SystemTest.java

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Revision 1.11 - (show annotations)
Tue Mar 15 19:47:07 2011 UTC (8 years, 5 months ago) by jsr166
Branch: MAIN
CVS Tags: release-1_7_0
Changes since 1.10: +1 -1 lines
Update Creative Commons license URL in legal notices

1 /*
2 * Written by Doug Lea with assistance from members of JCP JSR-166
3 * Expert Group and released to the public domain, as explained at
4 * http://creativecommons.org/publicdomain/zero/1.0/
5 * Other contributors include Andrew Wright, Jeffrey Hayes,
6 * Pat Fisher, Mike Judd.
7 */
8
9 import junit.framework.*;
10
11 public class SystemTest extends JSR166TestCase {
12 public static void main(String[] args) {
13 junit.textui.TestRunner.run(suite());
14 }
15
16 public static Test suite() {
17 return new TestSuite(SystemTest.class);
18 }
19
20 /**
21 * Worst case rounding for millisecs; set for 60 cycle millis clock.
22 * This value might need to be changed on JVMs with coarser
23 * System.currentTimeMillis clocks.
24 */
25 static final long MILLIS_ROUND = 17;
26
27 /**
28 * Nanos between readings of millis is no longer than millis (plus
29 * possible rounding).
30 * This shows only that nano timing not (much) worse than milli.
31 */
32 public void testNanoTime1() throws InterruptedException {
33 long m1 = System.currentTimeMillis();
34 Thread.sleep(1);
35 long n1 = System.nanoTime();
36 Thread.sleep(SHORT_DELAY_MS);
37 long n2 = System.nanoTime();
38 Thread.sleep(1);
39 long m2 = System.currentTimeMillis();
40 long millis = m2 - m1;
41 long nanos = n2 - n1;
42 assertTrue(nanos >= 0);
43 long nanosAsMillis = nanos / 1000000;
44 assertTrue(nanosAsMillis <= millis + MILLIS_ROUND);
45 }
46
47 /**
48 * Millis between readings of nanos is less than nanos, adjusting
49 * for rounding.
50 * This shows only that nano timing not (much) worse than milli.
51 */
52 public void testNanoTime2() throws InterruptedException {
53 long n1 = System.nanoTime();
54 Thread.sleep(1);
55 long m1 = System.currentTimeMillis();
56 Thread.sleep(SHORT_DELAY_MS);
57 long m2 = System.currentTimeMillis();
58 Thread.sleep(1);
59 long n2 = System.nanoTime();
60 long millis = m2 - m1;
61 long nanos = n2 - n1;
62
63 assertTrue(nanos >= 0);
64 long nanosAsMillis = nanos / 1000000;
65 assertTrue(millis <= nanosAsMillis + MILLIS_ROUND);
66 }
67
68 }

dl@cs.oswego.edu
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