维护插入顺序的并发集合 [英] A concurrent collection that maintains insertion order

问题描述

我正在寻找可以维持广告插入顺序的并发列表。有人推荐吗？

I'm looking for a concurrent list that can maintain the insertion order. Does anyone have some good recommendation ?

我从番石榴里看一些东西，例如SetFromMap，但在新版本中已弃用。

I look at some from guava e.g. SetFromMap, but they are deprecated in the new version.

谢谢。

推荐答案

如果大多数情况下是读操作，则写操作很少，并且没有太多元素，则可以使用 CopyOnWriteArrayList ，因为它是 List 的无锁实现，用于读取操作，因此它几乎不可能更快，但它对于写操作而言非常昂贵，因为每次写操作都需要重新构建整个列表，以便能够为其提供新的只读副本接下来的读取操作。

If you have mostly read operations, very few write operations and you don't have too much elements then you can use CopyOnWriteArrayList as it is a lock free implementation of a List for read operations such that it can hardly be faster but it is very costly for the write operations as for every single write, it re-builds the entire List to be able to provide a new read-only copy for the next read operations.

根据您的情况，您有很多写操作和很多元素要放入集合中， CopyOnWriteArrayList 显然不是您的选择。

As in your case, you have many write operations and a lot of elements to put in your collection, CopyOnWriteArrayList is clearly not an option for you.

在您的情况下，我建议使用一个线程安全的<您可以在 java.util.concurrent 包中找到code> Queue 。根据您的情况和您的JDK版本，最佳选择可能会发生变化，但是如果您特别不需要阻塞队列或 deque ，但只有一个纯集合，最佳选择可能是 ArrayBlockingQueue ， ConcurrentLinkedQueue 或 LinkedBlockingQueue ，但根据此基准测试结果（有点旧）， LinkedBlockingQueue 提供了最佳的整体性能。

What I suggest in your case, is to use one thread-safe Queue that you can find into the java.util.concurrent package. According to your context and your JDK version the best choice may change, but if you don't specifically need a blocking queue or a deque but only a pure collection, the best choices are probably ArrayBlockingQueue, ConcurrentLinkedQueue or LinkedBlockingQueue but according to this benchmark result (a little bit old), the LinkedBlockingQueue provides the best overall performances.

但是，当我们谈论性能时，最重要的建议是：始终在目标环境上进行测试，这是唯一有效的方法知道什么是您的最佳选择。。

But when we talk about performances, the first and most important advice is: always test on your target environment, it is the only valid way to know what is the best choice for you.

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