} while (oldHead != Waiter.TOMBSTONE);
      }
      // re-read valueField, if we get here then we must have observed a TOMBSTONE while trying to
      // add a waiter.
      // requireNonNull is safe because valueField is always set before TOMBSTONE.
      return getDoneValue(requireNonNull(valueField));
    }
    // If we get here then we have remainingNanos < SPIN_THRESHOLD_NANOS and there is no node on the
    // waiters list

    AfterEnqueuedTasks,

    /** Resumes after all other tasks, including tasks enqueued while yielding. */
    AfterOtherTasks,
  }

  /** Returns the task that was started, or null if there were no tasks to start. */
  private fun startNextTask(): SerialTask? {
    taskRunner.assertLockHeld()

    val index = serialTaskQueue.indexOfFirst { it.isReady() }
    if (index == -1) return null

  /** Return type from "contains the following elements" assertions. */
  public interface Ordered {
    /**
     * Attests that the expected values must not just be present but must be present in the order
     * they were given.
     */
    void inOrder();
  }

  @IgnoreJRERequirement // *should* be redundant with the annotation on SpliteratorTester
  private abstract static class GeneralSpliterator<E extends @Nullable Object> {

  /** Return type from "contains the following elements" assertions. */
  public interface Ordered {
    /**
     * Attests that the expected values must not just be present but must be present in the order
     * they were given.
     */
    void inOrder();
  }

  private abstract static class GeneralSpliterator<E extends @Nullable Object> {
    final Spliterator<E> spliterator;

    GeneralSpliterator(Spliterator<E> spliterator) {

  @SuppressWarnings("unchecked")
  public static <E> ImmutableSet<E> copyOf(Collection<? extends E> elements) {
    /*
     * TODO(lowasser): consider checking for ImmutableAsList here
     * TODO(lowasser): consider checking for Multiset here
     */
    // Don't refer to ImmutableSortedSet by name so it won't pull in all that code
    if (elements instanceof ImmutableSet && !(elements instanceof SortedSet)) {

       * parameters. If it were statically checked, the checker would still be OK with it, since
       * we're copying into a `contents` array whose type allows it to contain nulls. Still, it's
       * worth noting that we promise not to put nulls into the array in the first `size` elements.
       * We uphold that promise here because our callers promise that `elements` will not contain

        fail(
            "contents were not equal and in the same order: "
                + "expected = "
                + expected
                + ", actual = "
                + actual);
      }
    }

    if (expectedIter.hasNext() || actualIter.hasNext()) {
      // actual either had too few or too many elements
      fail(
          "contents were not equal and in the same order: "

  public void testTimeoutOnGetWorksCorrectly() throws InterruptedException, ExecutionException {

    // The task thread waits for the latch, so we expect a timeout here.
    try {
      future.get(20, MILLISECONDS);
      fail("Should have timed out trying to get the value.");
    } catch (TimeoutException expected) {
    } finally {
      latch.countDown();
    }
  }

        String result1 = purgeDocJob.execute();

        // Reset the flag
        deleteByQueryCalled = false;

        String result2 = purgeDocJob.execute();

        // Assert both executions were successful
        assertEquals("", result1);
        assertEquals("", result2);
        assertTrue(deleteByQueryCalled);
    }

    public void test_execute_withEmptyIndexName() {

     * until all the Listeners are installed and {@link #markReady()} is called. It is our caller's
     * responsibility to only call {@link #markReady()} if all services were new at the time this
     * method was called and when all the listeners were installed.
     */
    ServiceManagerState(ImmutableCollection<Service> services) {
      this.numberOfServices = services.size();
      servicesByState.putAll(NEW, services);