CODEWITHSUNDEEP
javamultithreading
user1870400
user1870400

Reputation: 6364

What really is Atomic?

What really is Atomic? since I have to choose some language to frame my question more clearly I would choose Java. I know that atomic means do everything or just rollback/do nothing. so say I have the following

public class Myclass {

    private boolean progress;

    public void setProgress(boolean progress) {
        this.progress = progress;
    }

    public boolean getProgress() {
       return progress;
    }

}

Now which of the following are thread-safe or atomic or both ? please treat each new line as a separate piece of code 

     -------------------
     getProgress(); // 
     ------------------

     ----------------------
     setProgress(true); //
     ----------------------

     -------------------
     getProgress()
     setProgress();
     -------------------

     --------------------
     setProgress();
     getProgress();
     --------------------

Which of these cases would make sense to use AtomicReference in java?

Upvotes: 0

Views: 81

Answers (1)

uylmz
uylmz

Reputation: 1552

From this:

What operations in Java are considered atomic?

I'd say none of them is atomic, since function call is not an atomic operation. But once you are in a function, assigning a boolean is atomic (just that line), returning it isn't.

For thread safety take a look at this:

Are java getters thread-safe?

Basically the old value of "progress" maybe cached inside cpu, so even if assigning it a new value was atomic (just that = line again) without a synched assignment (AtomicBoolean or synchronized getter/setter) it is thread-safe however there can be memory consistency errors so you may want to declare that variable volatile so other threads can see the most updated value.

Upvotes: 2

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