/** hasWaiters returns true when a thread is waiting, else false */
public void testHasWaiters() {
final Mutex sync = new Mutex();
final ConditionObject c = sync.newCondition();
final BooleanLatch acquired = new BooleanLatch();
Thread t =
newStartedThread(
new CheckedRunnable() {
public void realRun() throws InterruptedException {
sync.acquire();
assertHasWaitersLocked(sync, c, NO_THREADS);
assertFalse(sync.hasWaiters(c));
assertTrue(acquired.releaseShared(0));
c.await();
sync.release();
}
});
acquired.acquireShared(0);
sync.acquire();
assertHasWaitersLocked(sync, c, t);
assertHasExclusiveQueuedThreads(sync, NO_THREADS);
assertTrue(sync.hasWaiters(c));
c.signal();
assertHasWaitersLocked(sync, c, NO_THREADS);
assertHasExclusiveQueuedThreads(sync, t);
assertFalse(sync.hasWaiters(c));
sync.release();
awaitTermination(t);
assertHasWaitersUnlocked(sync, c, NO_THREADS);
}
/** hasWaiters(null) throws NullPointerException */
public void testHasWaitersNPE() {
final Mutex sync = new Mutex();
try {
sync.hasWaiters(null);
shouldThrow();
} catch (NullPointerException success) {
}
}
/** Checks that condition c has exactly the given waiter threads. */
void assertHasWaitersLocked(Mutex sync, ConditionObject c, Thread... threads) {
assertEquals(threads.length > 0, sync.hasWaiters(c));
assertEquals(threads.length, sync.getWaitQueueLength(c));
assertEquals(threads.length == 0, sync.getWaitingThreads(c).isEmpty());
assertEquals(threads.length, sync.getWaitingThreads(c).size());
assertEquals(
new HashSet<Thread>(sync.getWaitingThreads(c)),
new HashSet<Thread>(Arrays.asList(threads)));
}
/** hasWaiters throws IllegalMonitorStateException if not synced */
public void testHasWaitersIMSE() {
final Mutex sync = new Mutex();
final ConditionObject c = sync.newCondition();
try {
sync.hasWaiters(c);
shouldThrow();
} catch (IllegalMonitorStateException success) {
}
assertHasWaitersUnlocked(sync, c, NO_THREADS);
}