@Override
public void run() {
try {
for (int i = 0; i < 100; i++) {
int sharedBeforeChange = getSharedResource();
int shared = -1;
lock.lockShared();
try {
// do something needing write
lock.lockExclusively();
try {
shared = getSharedResource() + 1;
// do something
Thread.sleep(rnd.nextInt(50));
setSharedResource(shared);
lock.lockShared();
try {
// do something
Thread.sleep(rnd.nextInt(50));
} finally {
lock.unlock();
}
} finally {
lock.unlock();
}
} finally {
lock.unlock();
}
// kick other threads
Thread.yield();
// do something
Thread.sleep(rnd.nextInt(50));
// This code executes OUTSIDE of critical region!
int sharedAfterChange = getSharedResource();
// Assertion (note, it's STRICTLY LESS-THEN):
// sharedBeforeChange < shared = sharedAfterChange
if (!((sharedBeforeChange < shared) && (shared <= sharedAfterChange))) {
throw new IllegalStateException(
Thread.currentThread().getName()
+ " before:"
+ sharedBeforeChange
+ " shared:"
+ shared
+ " after:"
+ sharedAfterChange);
}
}
} catch (InterruptedException e) {
throw new IllegalStateException(e);
}
}
