RVS_GeneralObservableProtocol

public protocol RVS_GeneralObservableProtocol : AnyObject

This protocol makes any entity observable, by giving it the infrastructure to subscribe and track observers. It’s up to the implementor to actually use this to send messages.

Observables have to be classes. Observers don’t need to be classes.

There are two required components: a UUID, which needs to remain constant during the lifetime of the instance, and an Array of observers.

REQUIRED PROPERTIES

  • This is a unique ID for this Observer.

    If you are an observer, then you MUST supply a unique ID that remains constant throughout the lifetime of the instance.

    It must be declared as a stored property, and initialized with UUID(). After that, leave it alone.

    It should look like this, in your implementation:

    let uuid = UUID()

    Declaration

    Swift

    var uuid: UUID { get }

  • This is an Array of observers that subscribe to the observable instance.

    It should be noted that this would be a strong reference, if the observers were classes.

    Declaration

    Swift

    var observers: [RVS_GeneralObserverProtocol] { get set }

OPTIONAL METHODS

  • subscribe(_:) Default implementation

    This is how an observer subscribes to an Observable.

    Default Implementation

    The default will simply append the observer to our list.

    Declaration

    Swift

    @discardableResult
func subscribe(_: RVS_GeneralObserverProtocol) -> RVS_GeneralObserverProtocol?

    Return Value

    The subscribed element, if the subscription worked (or if the observer is already subscribed). Nil, otherwise. Can be ignored.

  • unsubscribe(_:) Default implementation

    This is how an observer unsubscribes from an Observable.

    Default Implementation

    The default will simply remove the observer from our list.

    Declaration

    Swift

    @discardableResult
func unsubscribe(_: RVS_GeneralObserverProtocol) -> RVS_GeneralObserverProtocol?

    Return Value

    The unsubscribed element, if the unsubscription worked (or if the observer is already unsubscribed). Nil, otherwise. Can be ignored.

  • unsubscribeAll() Default implementation

    Unsubscribes all currently subscribed entities.

    Default Implementation

    Default simply unsubscribes all the elements.

    Declaration

    Swift

    @discardableResult
func unsubscribeAll() -> [RVS_GeneralObserverProtocol]

    Return Value

    The subscribers that were removed. Can be ignored.

  • amISubscribed(_:) Default implementation

    An Observer can use this to see if they are already subscribed to an Observable.

    In the default implementation, this is called in the subscription/unsubscritption execution context, so that will be the thread used for the callback.

    Default Implementation

    The default will run through the Array, looking at UUIDs.

    Declaration

    Swift

    func amISubscribed(_: RVS_GeneralObserverProtocol) -> Bool

    Return Value

    True, if subscribed.

OPTIONAL CALLBACKS

  • observer(_:didSubscribe:) Default implementation

    This is method that is called when observers subscribe or unsubscribe. The default does nothing. This is called AFTER the fact, and only if the subscription status changed.

    Default Implementation

    The default does nothing.

    Declaration

    Swift

    func observer(_: RVS_GeneralObserverProtocol, didSubscribe: Bool)

    Parameters

    didSubscribe

    True, if this was a subscription. False, if not.