AtomicUpdater

Recursive, atomic updates. If there is an unguaranteed update of atomicity, it may loop indefinitely.

Update only if the existing data is in the expected state. If it is not in the expected state, it will not be updated.

Returns a new reference that is the result of the snapshot.

Atomically sets the field of the given object managed by this updater to the given value and returns the old value.

Atomically updates the field of the given object managed by this updater with the results of applying the given function, returning the previous value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads.

Gets the current value held in the field of the given object managed by this updater.

Sets the field of the given object managed by this updater to the given updated value. This operation is guaranteed to act as a volatile store with respect to subsequent invocations of compareAndSet.

Provides a way to create a snapshot if necessary. Usually not processed.

In that case, response is a reference, so if you change it, it may affect the value that other threads reference. To prevent this, use snapshot or compareAndSet to override snapshot and update.

 override def snapshot(w: W): W = w.snapshot()

 val old = getRef
 val newRef = get
 newRef.update(x -> y)
 compareAndSet(old, newRef)