1 |
|
/* |
2 |
< |
* Written by members of JCP JSR-166 Expert Group and released to the |
3 |
< |
* public domain. Use, modify, and redistribute this code in any way |
4 |
< |
* without acknowledgement. Other contributors include Andrew Wright, |
5 |
< |
* Jeffrey Hayes, Pat Fischer, Mike Judd. |
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/licenses/publicdomain |
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 TestCase { |
11 |
> |
public class SystemTest extends JSR166TestCase { |
12 |
|
public static void main(String[] args) { |
13 |
< |
junit.textui.TestRunner.run(suite()); |
13 |
> |
junit.textui.TestRunner.run(suite()); |
14 |
|
} |
15 |
< |
|
15 |
> |
|
16 |
|
public static Test suite() { |
17 |
< |
return new TestSuite(SystemTest.class); |
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 os 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() { |
33 |
< |
// Nanos between readings of millis must be no longer than millis |
34 |
< |
long m1 = System.currentTimeMillis(); |
35 |
< |
long n1 = System.nanoTime(); |
36 |
< |
|
37 |
< |
// Ensure some computation that is not optimized away. |
38 |
< |
long sum = 0; |
39 |
< |
for (long i = 1; i < 10000; ++i) |
40 |
< |
sum += i; |
41 |
< |
assertTrue(sum != 0); |
42 |
< |
|
43 |
< |
long n2 = System.nanoTime(); |
44 |
< |
|
45 |
< |
for (long i = 1; i < 10000; ++i) |
46 |
< |
sum -= i; |
47 |
< |
assertTrue(sum == 0); |
48 |
< |
|
49 |
< |
long m2 = System.currentTimeMillis(); |
37 |
< |
long millis = m2 - m1; |
38 |
< |
long nanos = n2 - n1; |
39 |
< |
|
40 |
< |
assertTrue(nanos >= 0); |
41 |
< |
assertTrue(nanos <= millis * 1000000); |
33 |
> |
try { |
34 |
> |
long m1 = System.currentTimeMillis(); |
35 |
> |
Thread.sleep(1); |
36 |
> |
long n1 = System.nanoTime(); |
37 |
> |
Thread.sleep(SHORT_DELAY_MS); |
38 |
> |
long n2 = System.nanoTime(); |
39 |
> |
Thread.sleep(1); |
40 |
> |
long m2 = System.currentTimeMillis(); |
41 |
> |
long millis = m2 - m1; |
42 |
> |
long nanos = n2 - n1; |
43 |
> |
assertTrue(nanos >= 0); |
44 |
> |
long nanosAsMillis = nanos / 1000000; |
45 |
> |
assertTrue(nanosAsMillis <= millis + MILLIS_ROUND); |
46 |
> |
} |
47 |
> |
catch (InterruptedException ie) { |
48 |
> |
unexpectedException(); |
49 |
> |
} |
50 |
|
} |
51 |
|
|
52 |
+ |
/** |
53 |
+ |
* Millis between readings of nanos is less than nanos, adjusting |
54 |
+ |
* for rounding. |
55 |
+ |
* This shows only that nano timing not (much) worse than milli. |
56 |
+ |
*/ |
57 |
|
public void testNanoTime2() { |
58 |
< |
// Millis between readings of nanos must be no longer than nanos |
59 |
< |
long n1 = System.nanoTime(); |
60 |
< |
long m1 = System.currentTimeMillis(); |
61 |
< |
|
62 |
< |
// Ensure some computation that is not optimized away. |
63 |
< |
long sum = 0; |
64 |
< |
for (long i = 1; i < 10000; ++i) |
65 |
< |
sum += i; |
66 |
< |
assertTrue(sum != 0); |
67 |
< |
|
68 |
< |
long m2 = System.currentTimeMillis(); |
69 |
< |
|
70 |
< |
for (long i = 1; i < 10000; ++i) |
71 |
< |
sum -= i; |
72 |
< |
assertTrue(sum == 0); |
73 |
< |
|
74 |
< |
long n2 = System.nanoTime(); |
75 |
< |
|
63 |
< |
long millis = m2 - m1; |
64 |
< |
long nanos = n2 - n1; |
65 |
< |
|
66 |
< |
assertTrue(nanos >= 0); |
67 |
< |
assertTrue(millis * 1000000 <= nanos); |
58 |
> |
try { |
59 |
> |
long n1 = System.nanoTime(); |
60 |
> |
Thread.sleep(1); |
61 |
> |
long m1 = System.currentTimeMillis(); |
62 |
> |
Thread.sleep(SHORT_DELAY_MS); |
63 |
> |
long m2 = System.currentTimeMillis(); |
64 |
> |
Thread.sleep(1); |
65 |
> |
long n2 = System.nanoTime(); |
66 |
> |
long millis = m2 - m1; |
67 |
> |
long nanos = n2 - n1; |
68 |
> |
|
69 |
> |
assertTrue(nanos >= 0); |
70 |
> |
long nanosAsMillis = nanos / 1000000; |
71 |
> |
assertTrue(millis <= nanosAsMillis + MILLIS_ROUND); |
72 |
> |
} |
73 |
> |
catch (InterruptedException ie) { |
74 |
> |
unexpectedException(); |
75 |
> |
} |
76 |
|
} |
77 |
|
|
78 |
|
} |
71 |
– |
|