是否有一个队列(PriorityQueue)实现也是一个集合? [英] Is there a Queue (PriorityQueue) implementation which is also a Set?

问题描述

我正在寻找 PriorityQueue 实现也是一个 Set.

I'm looking for a PriorityQueue implementation which is also a Set.

compareTo 实现，如果它的元素不能要求与 equals 的实现保持一致.

The compareTo implementation if its elements must not have the requirement to be consistent with the implementation of equals.

有没有这样的java实现?

Is there somewhere such a implementation for java?

更新:我现在使用 SortedSet 作为内部集合来实现它.所以我只需要实现缺少的方法来满足队列接口.我还忘了提到它也必须是一个有界队列，因此它具有容量并在达到容量时丢弃集合的最后一个元素.

Update: I implemented it now using a SortedSet as the internal collection. So I only had to implement the missing methods to satisfy the queue interface. I also forgot to mention that it also had to be a bounded queue, so it features a capacity and discards the last element of the set if capacity is reached.

推荐答案

如果队列具有类似 Set"的行为就足够了，我只是不想接受重复的条目，那么我认为，简单的解决方案可能是将 PriorityQueue 子类化并覆盖 add()、addAll() 和 offer() 方法喜欢:

If it's sufficient to have a queue with a 'Set-like' behaviour, iaw you just don't want to accept duplicate entries, then I think, an easy solution could be to subclass PriorityQueue and override the add(), addAll() and offer() methods like:

@Override
public boolean offer(E e) {
  if (contains(e)) {
    return false; 
  } else {
    return super.offer(e);
  }
}

顺便说一句 - add() 在内部调用 offer() ，所以也许只需覆盖 offer() 方法并执行那里的支票.

BTW - add() calls offer() internally, so maybe it's even enough to just override the offer() method and do the check there.

这篇关于是否有一个队列(PriorityQueue)实现也是一个集合?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！