DittoPendingIDSpecificOperation

public class DittoPendingIDSpecificOperation

These objects are returned when using findByID functionality on DittoCollections.

You can either call exec on the object to get an immediate return value, or you can establish either a live query or a subscription, which both work over time.

A live query, established by calling observeLocal, will notify you every time there’s an update to the document with the ID you provided in the preceding findByID call.

A subscription, established by calling subscribe, will act as a signal to other peers that you would like to receive updates from them about the document with the ID you provided in the preceding findByID call.

Typically, an app would set up a subscribe in some part of the application which is long-lived to ensure the device receives updates from the mesh. These updates will be automatically received and written into the local store. Elsewhere, where you need to use this data, an observeLocal can be used to notify you of the data, and all subsequent changes to the data.

Update and remove functionality is also exposed through this object.

  • Enables you to subscribe to changes that occur in relation to a document. Having a subscription acts as a signal to other peers that you are interested in receiving updates when local or remote changes are made to the relevant document. The returned DittoSubscription object must be kept in scope for as long as you want to keep receiving updates.

    Declaration

    Swift

    public func subscribe() -> DittoSubscription

    Return Value

    A DittoSubscription object that must be kept in scope for as long as you want to keep receiving updates for documents that match the query specified in the preceding chain.

  • Remove the document with the matching ID.

    Declaration

    Swift

    @discardableResult
public func remove() -> Bool

    Return Value

    true if the document was found and removed. false if the document wasn’t found and therefore wasn’t removed.

  • Evict the document with the matching ID.

    Declaration

    Swift

    @discardableResult
public func evict() -> Bool

    Return Value

    true if the document was found and evicted. false if the document wasn’t found and therefore wasn’t evicted.

  • Execute the find operation to return the document with the matching ID.

    Declaration

    Swift

    public func exec() -> DittoDocument?

    Return Value

    The DittoDocument with the ID provided in the findByID call or nil if the document was not found.

Observe

  • Enables you to listen for changes that occur in relation to a document. This won’t subscribe to receive changes made remotely by others and so it will only fire updates when a local change is made. If you want to receive remotely performed updates as well then also call subscribe separately after another findByID call that references the same document ID. The returned DittoLiveQuery object must be kept in scope for as long as you want the provided eventHandler to be called when an update occurs.

    Declaration

    Swift

    public func observeLocal(
    deliverOn queue: DispatchQueue = .main,
    eventHandler: @escaping (DittoDocument?, DittoSingleDocumentLiveQueryEvent) -> Void
) -> DittoLiveQuery

    Parameters

    queue

    The DispatchQueue that will be used to deliver live query updates. Defaults to DispatchQueue.main.
    eventHandler

    A closure that will be called every time there is a transaction committed to the store that involves a modification to the document with the relevant ID in the collection that observeLocal was called on.

    Return Value

    A DittoLiveQuery object that must be kept in scope for as long as you want to keep receiving updates.

  • Enables you to listen for changes that occur in relation to a document, and to signal when you are ready for the live query to deliver the next event. This won’t subscribe to receive changes made remotely by others and so it will only fire updates when a local change is made. If you want to receive remotely performed updates as well then also call subscribe separately after another findByID call that references the same document ID. The returned DittoLiveQuery object must be kept in scope for as long as you want the provided eventHandler to be called when an update occurs.

    Declaration

    Swift

    public func observeLocalWithNextSignal(
    deliverOn queue: DispatchQueue = .main,
    eventHandler: @escaping (DittoDocument?, DittoSingleDocumentLiveQueryEvent, @escaping DittoSignalNext) -> Void
) -> DittoLiveQuery

    Parameters

    queue

    The DispatchQueue that will be used to deliver live query updates. Defaults to DispatchQueue.main.
    eventHandler

    A closure that will be called every time there is a transaction committed to the store that involves a modification to the document with the relevant ID in the collection that observeLocal was called on.

    Return Value

    A DittoLiveQuery object that must be kept in scope for as long as you want to keep receiving updates.

Update

  • Update the document with the matching ID.

    Declaration

    Swift

    @discardableResult
public func update(
    _ closure: @escaping (DittoMutableDocument?) -> Void
) -> [DittoUpdateResult]

    Parameters

    closure

    A closure that gets called with the document matching the ID. If found, the document is a DittoMutableDocument, so you can call update-related functions on it. If the document is not found then the value provided to the closure will be nil.

    Return Value

    A list of DittoUpdateResults that describes the updates that were performed on the document.

  • Update the document with the matching ID.

    Throws

    DittoSwiftError.

    Declaration

    Swift

    @available(*, deprecated, message: "Codable APIs will be removed in the future.")
public func update<T>(using newValue: T) throws where T : Decodable, T : Encodable

    Parameters

    using

    An object representing the desired new state of the document’s value.

  • Undocumented

    Declaration

    Swift

    typealias Snapshot = (document: DittoDocument?, event: DittoSingleDocumentLiveQueryEvent)

  • A Combine publisher that produces a document matching the requested ID, if it can be found.

    See more

    Declaration

    Swift

    struct SingleDocumentLiveQueryPublisher : Publisher

  • A Combine publisher that produces a document matching the requested ID, if it can be found.

    Declaration

    Swift

    func singleDocumentLiveQueryPublisher() -> SingleDocumentLiveQueryPublisher

    Return Value

    A SingleDocumentLiveQueryPublisher which has an output of (DittoDocument?, DittoSingleDocumentLiveQueryEvent)