ListObserver

public protocol ListObserver : AnyObject

Implement the ListObserver protocol to observe changes to a list of NSManagedObjects. ListObservers may register themselves to a ListMonitor‘s addObserver(_:) method:

let monitor = dataStack.monitorList(
    From<Person>(),
    OrderBy(.ascending("lastName"))
)
monitor.addObserver(self)

  • The NSManagedObject type for the observed list

    Declaration

    Swift

    associatedtype ListEntityType : DynamicObject

  • Handles processing just before a change to the observed list occurs. (Optional) The default implementation does nothing.

    Default Implementation

    Declaration

    Swift

    func listMonitorWillChange(
    _ monitor: ListMonitor<ListEntityType>,
    sourceIdentifier: Any?
)

    Parameters

    monitor

    the ListMonitor monitoring the list being observed
    sourceIdentifier

    an optional identifier provided by the transaction source
  • listMonitorWillChange(_:) Default implementation

    Handles processing just before a change to the observed list occurs. (Optional) The default implementation does nothing.

    Default Implementation

    Declaration

    Swift

    func listMonitorWillChange(
    _ monitor: ListMonitor<ListEntityType>
)

    Parameters

    monitor

    the ListMonitor monitoring the list being observed

  • Handles processing right after a change to the observed list occurs. (Required)

    Default Implementation

    Declaration

    Swift

    func listMonitorDidChange(
    _ monitor: ListMonitor<ListEntityType>,
    sourceIdentifier: Any?
)

    Parameters

    monitor

    the ListMonitor monitoring the object being observed
    sourceIdentifier

    an optional identifier provided by the transaction source

  • Handles processing right after a change to the observed list occurs. (Required)

    Declaration

    Swift

    func listMonitorDidChange(
    _ monitor: ListMonitor<ListEntityType>
)

    Parameters

    monitor

    the ListMonitor monitoring the object being observed

  • This method is broadcast from within the ListMonitor‘s refetch(...) method to let observers prepare for the internal NSFetchedResultsController’s pending change to its predicate, sort descriptors, etc. (Optional)

    Important

    All ListMonitor access between listMonitorWillRefetch(_:) and listMonitorDidRefetch(_:) will raise and assertion. The actual refetch will happen after the NSFetchedResultsController’s last controllerDidChangeContent(_:) notification completes.

    Default Implementation

    Declaration

    Swift

    func listMonitorWillRefetch(
    _ monitor: ListMonitor<ListEntityType>,
    sourceIdentifier: Any?
)

    Parameters

    monitor

    the ListMonitor monitoring the object being observed
    sourceIdentifier

    an optional identifier provided by the transaction source
  • listMonitorWillRefetch(_:) Default implementation

    This method is broadcast from within the ListMonitor‘s refetch(...) method to let observers prepare for the internal NSFetchedResultsController’s pending change to its predicate, sort descriptors, etc. (Optional)

    Important

    All ListMonitor access between listMonitorWillRefetch(_:) and listMonitorDidRefetch(_:) will raise and assertion. The actual refetch will happen after the NSFetchedResultsController’s last controllerDidChangeContent(_:) notification completes.

    Default Implementation

    Declaration

    Swift

    func listMonitorWillRefetch(
    _ monitor: ListMonitor<ListEntityType>
)

    Parameters

    monitor

    the ListMonitor monitoring the object being observed

  • After the ListMonitor‘s refetch(...) method is called, this method is broadcast after the NSFetchedResultsController’s last controllerDidChangeContent(_:) notification completes. (Required)

    Important

    When listMonitorDidRefetch(_:) is called it should be assumed that all ListMonitor’s previous data have been reset, including counts, objects, and persistent stores.

    Default Implementation

    Declaration

    Swift

    func listMonitorDidRefetch(
    _ monitor: ListMonitor<ListEntityType>,
    sourceIdentifier: Any?
)

    Parameters

    monitor

    the ListMonitor monitoring the object being observed
    sourceIdentifier

    an optional identifier provided by the transaction source

  • After the ListMonitor‘s refetch(...) method is called, this method is broadcast after the NSFetchedResultsController’s last controllerDidChangeContent(_:) notification completes. (Required)

    Important

    When listMonitorDidRefetch(_:) is called it should be assumed that all ListMonitor’s previous data have been reset, including counts, objects, and persistent stores.

    Declaration

    Swift

    func listMonitorDidRefetch(
    _ monitor: ListMonitor<ListEntityType>
)

    Parameters

    monitor

    the ListMonitor monitoring the object being observed