/**
   * Asynchronous sequence update operation. Will add given amount to the sequence value.
   *
   * @param l Increment amount.
   * @param updateCall Cache call that will update sequence reservation count in accordance with l.
   * @param updated If {@code true}, will return sequence value after update, otherwise will return
   *     sequence value prior to update.
   * @return Future indicating sequence value.
   * @throws GridException If update failed.
   */
  private GridFuture<Long> internalUpdateAsync(
      long l, @Nullable Callable<Long> updateCall, boolean updated) throws GridException {
    checkRemoved();

    A.ensure(l > 0, " Parameter mustn't be less then 1: " + l);

    lock.lock();

    try {
      // If reserved range isn't exhausted.
      if (locVal + l <= upBound) {
        long curVal = locVal;

        locVal += l;

        return new GridFinishedFuture<Long>(ctx.kernalContext(), updated ? locVal : curVal);
      }
    } finally {
      lock.unlock();
    }

    if (updateCall == null) updateCall = internalUpdate(l, updated);

    while (true) {
      if (updateGuard.compareAndSet(false, true)) {
        try {
          // This call must be outside lock.
          return ctx.closures().callLocalSafe(updateCall, true);
        } finally {
          lock.lock();

          try {
            updateGuard.set(false);

            cond.signalAll();
          } finally {
            lock.unlock();
          }
        }
      } else {
        lock.lock();

        try {
          while (locVal >= upBound && updateGuard.get()) {
            try {
              cond.await(500, MILLISECONDS);
            } catch (InterruptedException e) {
              throw new GridInterruptedException(e);
            }
          }

          checkRemoved();

          // If reserved range isn't exhausted.
          if (locVal + l <= upBound) {
            long curVal = locVal;

            locVal += l;

            return new GridFinishedFuture<Long>(ctx.kernalContext(), updated ? locVal : curVal);
          }
        } finally {
          lock.unlock();
        }
      }
    }
  }
  /**
   * Synchronous sequence update operation. Will add given amount to the sequence value.
   *
   * @param l Increment amount.
   * @param updateCall Cache call that will update sequence reservation count in accordance with l.
   * @param updated If {@code true}, will return sequence value after update, otherwise will return
   *     sequence value prior to update.
   * @return Sequence value.
   * @throws GridException If update failed.
   */
  private long internalUpdate(long l, @Nullable Callable<Long> updateCall, boolean updated)
      throws GridException {
    checkRemoved();

    assert l > 0;

    lock.lock();

    try {
      // If reserved range isn't exhausted.
      if (locVal + l <= upBound) {
        long curVal = locVal;

        locVal += l;

        return updated ? locVal : curVal;
      }
    } finally {
      lock.unlock();
    }

    if (updateCall == null) updateCall = internalUpdate(l, updated);

    while (true) {
      if (updateGuard.compareAndSet(false, true)) {
        try {
          // This call must be outside lock.
          return CU.outTx(updateCall, ctx);
        } finally {
          lock.lock();

          try {
            updateGuard.set(false);

            cond.signalAll();
          } finally {
            lock.unlock();
          }
        }
      } else {
        lock.lock();

        try {
          while (locVal >= upBound && updateGuard.get()) {
            try {
              cond.await(500, MILLISECONDS);
            } catch (InterruptedException e) {
              throw new GridInterruptedException(e);
            }
          }

          checkRemoved();

          // If reserved range isn't exhausted.
          if (locVal + l <= upBound) {
            long curVal = locVal;

            locVal += l;

            return updated ? locVal : curVal;
          }
        } finally {
          lock.unlock();
        }
      }
    }
  }