package Breccia.Web.imager; import java.util.concurrent.atomic.AtomicReference; import static java.util.Objects.requireNonNull​; final class ImageabilityReference extends AtomicReference { // An alias, for concision. ImageabilityReference( final Imageability i ) { super( requireNonNull​( i )); }} // Setters too might be so guarded, and guarded for valid state transitions, // but that is not the purpose of this class. // Copyright © 2020 Michael Allan. Licence MIT.