问题描述
我将 ConcurrentQueue 用于共享数据结构，其目的是保存传递给它的最后 N 个对象(某种历史记录).
I'm using ConcurrentQueue for a shared data structure which purpose is holding the last N objects passed to it (kind of history).
假设我们有一个浏览器并且我们想要最近 100 个浏览的 Url.我想要一个队列，当容量已满(历史上的 100 个地址)时，它会在新条目插入(入队)时自动丢弃(出队)最旧的(第一个)条目.
Assume we have a browser and we want to have the last 100 browsed Urls. I want a queue which automatically drop (dequeue) the oldest (first) entry upon new entry insertion (enqueue) when the capacity gets full (100 addresses in history).
我怎样才能使用 System.Collections 来做到这一点?
How can I accomplish that using System.Collections ?
推荐答案
我会写一个包装类，它在 Enqueue 上会检查 Count，然后当计数超过限制时 Dequeue.
I would write a wrapper class that on Enqueue would check the Count and then Dequeue when the count exceeds the limit.
public class FixedSizedQueue<T>
{
ConcurrentQueue<T> q = new ConcurrentQueue<T>();
private object lockObject = new object();
public int Limit { get; set; }
public void Enqueue(T obj)
{
q.Enqueue(obj);
lock (lockObject)
{
T overflow;
while (q.Count > Limit && q.TryDequeue(out overflow)) ;
}
}
}
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