63 |
|
ThreadLocalRandom rnd = ThreadLocalRandom.current(); |
64 |
|
final java.lang.reflect.Method m; |
65 |
|
try { |
66 |
< |
m = ThreadLocalRandom.class.getDeclaredMethod( |
67 |
< |
"next", new Class[] { int.class }); |
66 |
> |
m = ThreadLocalRandom.class.getDeclaredMethod("next", int.class); |
67 |
|
m.setAccessible(true); |
68 |
|
} catch (SecurityException acceptable) { |
69 |
|
// Security manager may deny access |
354 |
|
// Don't use main thread's ThreadLocalRandom - it is likely to |
355 |
|
// be polluted by previous tests. |
356 |
|
final AtomicReference<ThreadLocalRandom> threadLocalRandom = |
357 |
< |
new AtomicReference<ThreadLocalRandom>(); |
357 |
> |
new AtomicReference<>(); |
358 |
|
final AtomicLong rand = new AtomicLong(); |
359 |
|
|
361 |
– |
long firstRand = 0; |
362 |
– |
ThreadLocalRandom firstThreadLocalRandom = null; |
363 |
– |
|
360 |
|
Runnable getRandomState = new CheckedRunnable() { |
361 |
|
public void realRun() { |
362 |
|
ThreadLocalRandom current = ThreadLocalRandom.current(); |
363 |
|
assertSame(current, ThreadLocalRandom.current()); |
368 |
– |
// test bug: the following is not guaranteed and not true in JDK8 |
369 |
– |
// assertNotSame(current, threadLocalRandom.get()); |
364 |
|
rand.set(current.nextLong()); |
365 |
|
threadLocalRandom.set(current); |
366 |
|
}}; |
367 |
|
|
368 |
< |
Thread first = newStartedThread(getRandomState); |
369 |
< |
awaitTermination(first); |
370 |
< |
firstRand = rand.get(); |
371 |
< |
firstThreadLocalRandom = threadLocalRandom.get(); |
368 |
> |
awaitTermination(newStartedThread(getRandomState)); |
369 |
> |
long firstRand = rand.get(); |
370 |
> |
ThreadLocalRandom firstThreadLocalRandom = threadLocalRandom.get(); |
371 |
> |
assertNotNull(firstThreadLocalRandom); |
372 |
|
|
373 |
|
for (int i = 0; i < NCALLS; i++) { |
374 |
< |
Thread t = newStartedThread(getRandomState); |
375 |
< |
awaitTermination(t); |
374 |
> |
awaitTermination(newStartedThread(getRandomState)); |
375 |
> |
if (testImplementationDetails) |
376 |
> |
// ThreadLocalRandom has been a singleton since jdk8. |
377 |
> |
assertSame(firstThreadLocalRandom, threadLocalRandom.get()); |
378 |
|
if (firstRand != rand.get()) |
379 |
|
return; |
380 |
|
} |
381 |
|
fail("all threads generate the same pseudo-random sequence"); |
382 |
|
} |
383 |
|
|
384 |
+ |
/** |
385 |
+ |
* Repeated calls to nextBytes produce at least values of different signs for every byte |
386 |
+ |
*/ |
387 |
+ |
public void testNextBytes() { |
388 |
+ |
ThreadLocalRandom rnd = ThreadLocalRandom.current(); |
389 |
+ |
int n = rnd.nextInt(1, 20); |
390 |
+ |
byte[] bytes = new byte[n]; |
391 |
+ |
outer: |
392 |
+ |
for (int i = 0; i < n; i++) { |
393 |
+ |
for (int tries = NCALLS; tries-->0; ) { |
394 |
+ |
byte before = bytes[i]; |
395 |
+ |
rnd.nextBytes(bytes); |
396 |
+ |
byte after = bytes[i]; |
397 |
+ |
if (after * before < 0) |
398 |
+ |
continue outer; |
399 |
+ |
} |
400 |
+ |
fail("not enough variation in random bytes"); |
401 |
+ |
} |
402 |
+ |
} |
403 |
+ |
|
404 |
+ |
/** |
405 |
+ |
* Filling an empty array with random bytes succeeds without effect. |
406 |
+ |
*/ |
407 |
+ |
public void testNextBytes_emptyArray() { |
408 |
+ |
ThreadLocalRandom.current().nextBytes(new byte[0]); |
409 |
+ |
} |
410 |
+ |
|
411 |
+ |
public void testNextBytes_nullArray() { |
412 |
+ |
try { |
413 |
+ |
ThreadLocalRandom.current().nextBytes(null); |
414 |
+ |
shouldThrow(); |
415 |
+ |
} catch (NullPointerException success) {} |
416 |
+ |
} |
417 |
+ |
|
418 |
|
} |