java - Java 中的异步事件调度

Question

我正在将 C# 程序移植到 Java，该程序大量使用委托(delegate)和委托(delegate)的 BeginInvoke 方法来异步通知事件。以数据通信线程为例。它可能必须将其状态和 GUI 通知另一个工作线程。

在我看来，通知不同类的各种事件的最佳方法是拥有一个 IClassNameHereWatcher 接口(interface)，该接口(interface)定义类“发布”事件的所有事件类型需要通知，然后每个需要监听的类将实现此接口(interface)并将自己注册为监听器。我不太确定的是如何使它异步。这大致是我所指的内容:

public interface IFrobWatcher {
    void frobDidSomething();
    void frobReceivedData(object data);
}

public class Frob implements Runnable {
    List<IFrobWatcher> watchers = new ArrayList<IFrobWatcher>();

    private void run() {
        while (true) {
            // Long running task
            if (blah) notifyWeDidSomething();
            notifyOfData(someDataObject);
        }
    }

    public void addWatcher(IFrobWatcher watcher) {
        watchers.Add(watcher);
    }

    private void notifyWeDidSomething() {
        for (IFrobWatcher watcher : watchers) {
            watcher.frobDidSomething(); // How do I make this asynchronous?
        }
    }

    private void notifyOfData(object someDataObject) {
        for (IFrobWatcher watcher : watchers) {
            watcher.frobReceivedData(someDataObject); // How do I make this asynchronous?
        }
    }

}

public class FrobWatcher implements IFrobWatcher {
    private Frob frobToWatch;

    public FrobWatcher(Frob frob) {
        frobToWatch = frob;
        frobToWatch.addListener(this);
    }

    public void FrobDidSomething() {
        System.out.println("Frob did something!");
    }

    public void FrobReceivedData(object received) {
        System.out.println("Frob received: " + received.ToString());
    }

    public static void main(string[] args) {
        Frob f = new Frob();
        FrobWatcher fw = new FrobWatcher(f);
        (new Thread(f)).start();
    }
}

这是一个相当简化的示例，但希望它能传达我正在寻找的内容。如果有什么不清楚或没有意义，请发表评论，我会尝试澄清或修复示例。

Answer 1

我会推荐 java.util.concurrent 包中的执行器。这就是异步回调在 Raptor framework 中的处理方式:

scheduler = Executors.newSingleThreadScheduledExecutor();
scheduler.scheduleAtFixedRate(
    filesPoller, 0 /*initial delay*/,
    checkInterval,
    TimeUnit.MILLISECONDS
);

注意。此计划是重复的。