Java 是否有可索引的多队列线程池?

问题描述

是否有这样的 Java 类:

Is there a Java class such that:

1. 可以通过 id 添加可执行任务，保证所有具有相同 id 的任务不会同时运行
2. 线程数可以限制为固定数量

一个朴素的地图解决方案很容易解决(1)，但很难管理(2).同样，我所知道的所有线程池类都将从单个队列中提取，这意味着 (1) 无法保证.

A naive solution of a Map would easily solve (1), but it would be difficult to manage (2). Similarly, all thread pooling classes that I know of will pull from a single queue, meaning (1) is not guaranteed.

欢迎涉及外部库的解决方案.

Solutions involving external libraries are welcome.

推荐答案

如果你没有找到开箱即用的东西，那么推出你自己的应该不难.您可以做的一件事是将每个任务包装在一个简单的类中，该类读取每个 id 唯一的队列，例如:

If you don't find something that does this out of the box, it shouldn't be hard to roll your own. One thing you could do is to wrap each task in a simple class that reads on a queue unique per id, e.g.:

public static class SerialCaller<T> implements Callable<T> {
    private final BlockingQueue<Caller<T>> delegates;

    public SerialCaller(BLockingQueue<Caller<T>> delegates) {
        this.delegates = delegates;
    }

    public T call() throws Exception {
        return delegates.take().call();
    }
}

维护 id 到队列的映射应该很容易，以便提交任务.即满足条件(1)，然后可以寻找条件(2)的简单解法，如执行者.newFixedThreadPool

It should be easy to maintain a map of ids to queues for submitting tasks. That satisfies condition (1), and then you can look for simple solutions to condition (2), such as Executors. newFixedThreadPool

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