FairCallQueue extends AbstractQueue<E> implements BlockingQueue<E> { @Override public E poll(long timeout, TimeUnit unit) throws InterruptedException { return semaphore.tryAcquire(timeout, unit) ? removeNextElement() : null; } FairCallQueue(int priorityLevels, int capacity, String ns,
      Configuration conf); @Override boolean add(E e); @Override void put(E e); @Override boolean offer(E e, long timeout, TimeUnit unit); @Override boolean offer(E e); @Override E take(); @Override E poll(long timeout, TimeUnit unit); @Override E poll(); @Override E peek(); @Override int size(); @Override Iterator<E> iterator(); @Override int drainTo(Collection<? super E> c, int maxElements); @Override int drainTo(Collection<? super E> c); @Override int remainingCapacity(); int[] getQueueSizes(); long[] getOverflowedCalls(); @VisibleForTesting void setMultiplexer(RpcMultiplexer newMux); @Deprecated
  static final int IPC_CALLQUEUE_PRIORITY_LEVELS_DEFAULT; @Deprecated
  static final String IPC_CALLQUEUE_PRIORITY_LEVELS_KEY; static final Logger LOG; }
@Test public void testPollReturnsNullWhenEmpty() { assertNull(fcq.poll()); }
@Test public void testPollTimeout() throws InterruptedException { assertNull(fcq.poll(10, TimeUnit.MILLISECONDS)); }