确保元素唯一性的队列? [英] A Queue that ensure uniqueness of the elements?

问题描述

我正在寻找 java.util.Queue 或 Google 集合中行为类似于队列的某些内容的实现，但还要确保队列的每个元素都是唯一的.(所有进一步插入将无效)

I'm looking for a implementation of java.util.Queue or something in the Google collection who behave like a Queue, but also ensure that each element of the queue is unique. (all further insertion will have no effect)

这是可能的，还是我必须手动完成?

It's that possible, or will I have to do it by hand?

现在我正在使用队列和 LinkedList 实现，并在插入前检查唯一性.(我使用侧图来执行此操作，在队列之前/之后从侧图中添加/删除元素).我不太喜欢.

For now I'm using a Queue, with a LinkedList implementation, and I check the uniqueness before insertion. ( I use a side Map for doing this, add / remove element from the side map before / after the queu ). I don't like it too much.

欢迎任何输入.如果它不在 java.util 包中，那么这可能是个坏主意?

Any input is welcome. If it's not in the java.util package, then maybe it's a bad idea?

推荐答案

LinkedHashSet?它的迭代器保留插入顺序，但因为它是一个 Set，所以它的元素是唯一的.

How about a LinkedHashSet? Its iterator preserves insertion order, but because it's a Set, its elements are unique.

正如其文档所说，

请注意，如果元素被重新插入到集合中，则插入顺序不会受到影响.

Note that insertion order is not affected if an element is re-inserted into the set.

为了有效地从这个队列"的头部移除元素，通过它的迭代器:

In order to efficiently remove elements from the head of this "queue", go through its iterator:

Iterator<?> i = queue.iterator();
...
Object next = i.next();
i.remove();

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