如何在后台执行服务并检查其状态

Question

I'm executing a heavy calculation on the server. The execution is launched from the front and the front is checking the status of the execution each 3 sec.

So I wrote a service like the following :

public class SomeService {

    private final ExecutorService executor = Executors.newSingleThreadExecutor();
    private final Future<?> noop = CompletableFuture.completedFuture(null);
    private final AtomicReference<Future<?>> currentExecution = new AtomicReference<>(noop);


    public void execute() {

        Future<?> execution = executor.submit(() -> {
            // do some heavy calculation here
            // ...
            // ...

            currentExecution.set(noop);
        });

        currentExecution.set(execution);
    }

    public boolean isRunning() {
        return !currentExecution.get().isDone();
    }
}

isRunning method is exposed as an api to the front.

I'm wondering if there's bugs here?

Maybe there's another elegant solution for this requirement?

Answer 1

A simple flag, set when the computation completes, would suffice, as long as it's volatile .

private volatile boolean done;

public void execute() {
    executor.submit(() -> {
        /* Do some heavy calculation here. */
        done = true;
    });
}

public boolean isDone() {
    return done;
}