}

    private void succeedsInValueSet(
        @Nullable ValueEntry<K, V> pred, @Nullable ValueEntry<K, V> succ) {
      if (pred == null) {
        firstEntry = succ;
      } else {
        pred.successorInValueSet = succ;
      }
      if (succ == null) {
        lastEntry = pred;
      } else {
        succ.predecessorInValueSet = pred;
      }
    }

    for (int i : new int[] {0, SIZE - 1}) {
      double prev = 0.0;
      double unused = Math.E + Math.PI;
      for (double x : VALUES) {
        assertBitEquals(prev, aa.get(i));
        assertFalse(aa.compareAndSet(i, unused, x));
        assertBitEquals(prev, aa.get(i));
        assertTrue(aa.compareAndSet(i, prev, x));
        assertBitEquals(x, aa.get(i));
        prev = x;
      }
    }
  }

    NodeConnection(N node) {
      this.node = checkNotNull(node);
    }

    static final class Pred<N> extends NodeConnection<N> {
      Pred(N node) {
        super(node);
      }

      @Override
      public boolean equals(@Nullable Object that) {
        if (that instanceof Pred) {
          return this.node.equals(((Pred<?>) that).node);
        } else {
          return false;
        }
      }

      @Override

    /** Constructor for the header node. */
    AvlNode() {
      this.elem = null;
      this.elemCount = 1;
    }

    // For discussion of pred() and succ(), see the comment on the pred and succ fields.

    private AvlNode<E> pred() {
      return requireNonNull(pred);
    }

    private AvlNode<E> succ() {
      return requireNonNull(succ);
    }

        final String pref = ComponentUtil.getFessConfig().getQueryJsonDefaultPreference();
        if (PREFERENCE_QUERY.equals(pref)) {
            return Integer.toString(query.hashCode());
        }
        if (StringUtil.isNotBlank(pref)) {
            return pref;
        }
        return null;
    }

    /**

    SettableFuture<String> orig = SettableFuture.create();
    SettableFuture<String> prev = orig;
    for (int i = 0; i < 100000; i++) {
      SettableFuture<String> curr = SettableFuture.create();
      prev.setFuture(curr);
      prev = curr;
    }
    // prev represents the 'innermost' future
    prev.set("done");
    assertTrue(orig.isDone());
  }

    checkNotNull(comparator);
    Iterator<? extends T> it = iterable.iterator();
    if (it.hasNext()) {
      T prev = it.next();
      while (it.hasNext()) {
        T next = it.next();
        if (comparator.compare(prev, next) > 0) {
          return false;
        }
        prev = next;
      }
    }
    return true;
  }

  /**

   *
   * <pre>
   * for (Foo foo : foos) {
   *   try {
   *     foo.bar();
   *   } catch (BarException | RuntimeException | Error t) {
   *     failure = t;
   *   }
   * }
   * if (failure != null) {
   *   throwIfInstanceOf(failure, BarException.class);
   *   throwIfUnchecked(failure);
   *   throw new AssertionError(failure);
   * }
   * </pre>
   *
   * @since 20.0
   */

    SettableFuture<String> orig = SettableFuture.create();
    SettableFuture<String> prev = orig;
    for (int i = 0; i < 100000; i++) {
      SettableFuture<String> curr = SettableFuture.create();
      prev.setFuture(curr);
      prev = curr;
    }
    // prev represents the 'innermost' future
    prev.set("done");
    assertTrue(orig.isDone());
  }

    restart:
    while (true) {
      Waiter pred = null;
      Waiter curr = waitersField;
      if (curr == Waiter.TOMBSTONE) {
        return; // give up if someone is calling complete
      }
      Waiter succ;
      while (curr != null) {
        succ = curr.next;
        if (curr.thread != null) { // we aren't unlinking this node, update pred.
          pred = curr;