What is the safest way to check AtomicBoolean and perform something?

Question

Are any ways to make this operations like one operatinon (kind of custom atomic)?

 if (!isShutdownStarted.get()
            && !QUEUE.contains(request.getUserEmail())) {
        try {
            QUEUE.add(request.getUserEmail());
        } 
 //...
 }

Code in other thread

@Override
public void contextDestroyed(ServletContextEvent servletContextEvent) {
    PaymentClient.isShutdownStarted.set(true);
    while (!PaymentClient.QUEUE.isEmpty());
}

Answer 1

You cannot use an AtomicBoolean to make another operation or sequence of operations atomic.

If you need to make an intrinsically non-atomic operation or sequence atomic, you need to use locking; eg a primitive mutex, a Lock or something equivalent.