code: public void update(int element, double priority) {
      this.doImport(element);
      final double q = this.prior.get(element);
      if (Double.compare(q, priority) == 0)
        return;
      this.prior.set(element, priority);
      if (this.pos.get(element) < 0)
        return;
      if (priority < q)
        this.down(element);
      if (q < priority)
        this.up(element);
    }
docs: Updated the priority of a given element.
  @param element  the element
  @param priority the new priority