CODEWITHSUNDEEP
javamultithreadingcallable
Majid Azimi
Majid Azimi

Reputation: 5745

Event Driven Future<V> - Thread Pool

We use callable<V> and Future<V> to receive the result of a terminated thread from a thread pool. We should call get() to receive the returned result. My problem is: it is not event driven. Is there any framework to get result like SIGCHLD for child processes in C? I want something like this:(the thread pool will call this function when each thread in the pool finished the job)

public void fetchResult(Thread t, Runnable r, Future<Integer> result) {
    Integer x = result.get();
    /* handle x */
    /* also we have Thread and Runnable object that has terminated */
}

Upvotes: 4

Views: 1513

Answers (2)

jtahlborn
jtahlborn

Reputation: 53694

you might want to check out the ThreadPoolExecutor.afterExecute() method. it's called after each task completes. you could create a custom subclass of ThreadPoolExecutor which has the event based callback behavior you desire.

Upvotes: 1

Johan Sj&#246;berg
Johan Sj&#246;berg

Reputation: 49187

You could easily create an event driven template. The following pseudo-code illustrates one approach. 

abstract class EventTemplate<T> implements Runnable {
    private BlockingQueue<T> queue; 

    public void submit(Callable<T> callable) {
        queue.add(callable);
    }

    public abstract void handleEvent(T t);

    public void run() {
        for(;;) handleEvent(queue.take());
    }

    public void start() {
         new Thread(this).start();
    }
}

Classes can the extend the template

class FooEventHandler extends EventTemplate<Foo> {
    public void handleEvent(Foo foo) {
        // do something 
    }
}

Which can be instantiated

new FooEventHandler().start();

Upvotes: 0

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