Class

NotificationQueue

A notification center buffer.

Overview

Whereas a notification center distributes notifications when posted, notifications placed into the queue can be delayed until the end of the current pass through the run loop or until the run loop is idle. Duplicate notifications can also be coalesced so that only one notification is sent although multiple notifications are posted. A notification queue maintains notifications (instances of NSNotification) generally in a first in first out (FIFO) order. When a notification rises to the front of the queue, the queue posts it to the notification center, which in turn dispatches the notification to all objects registered as observers.

Every thread has a default notification queue, which is associated with the default notification center for the task. You can create your own notification queues and have multiple queues per center and thread.

Topics

Creating Notification Queues

init(notificationCenter: NotificationCenter)

Initializes and returns a notification queue for the specified notification center.

Getting the Default Queue

class var `default`: NotificationQueue

Returns the default notification queue for the current thread.

Managing Notifications

func enqueue(Notification, postingStyle: NotificationQueue.PostingStyle)

Adds a notification to the notification queue with a specified posting style.

func enqueue(Notification, postingStyle: NotificationQueue.PostingStyle, coalesceMask: NotificationQueue.NotificationCoalescing, forModes: [RunLoopMode]?)

Adds a notification to the notification queue with a specified posting style, criteria for coalescing, and runloop mode.

func dequeueNotifications(matching: Notification, coalesceMask: Int)

Removes all notifications from the queue that match a provided notification using provided matching criteria.

Constants

struct NotificationQueue.NotificationCoalescing

These constants specify how notifications are coalesced.

enum NotificationQueue.PostingStyle

These constants specify when notifications are posted.

Relationships

Inherits From

Conforms To

See Also

Notifications

struct Notification

A container for information broadcast through a notification center to all registered observers.

class NotificationCenter

A notification dispatch mechanism that enables the broadcast of information to registered observers.