EODelayedObserver
- Inherits from:
- NSObject
- Conforms to:
- EODelayedObserving
- NSObject (NSObject)
Declared in:
- EOControl/EOObserver.h
Class Description
The EODelayedObserver class is a part of EOControl's change tracking mechanism. It is an abstract superclass that defines the basic functionality for coalescing change notifications for multiple objects and postponing notification according to a prioritized queue. For an overview of the general change tracking mechanism, see "Tracking Enterprise Objects Changes" in the introduction to the EOControl Framework.
EODelayedObserver is primarily used to implement the interface layer's associations and wouldn't ordinarily be used outside the scope of a Java Client or Application Kit application (not in a command line tool or WebObjects application, for example). See the EODelayedObserverQueue class specification for general information.
You would never create an instance of EODelayedObserver. Instead, you use subclasses-typically EOAssociations (EOInterface). For information on creating your own EODelayedObserver subclass, see "Creating a Subclass of EODelayedObserver" .
Constants
In EOObserver.h, EOControl defines the
enumeration type EOObserverPriority
to
represent the priority of a notification in the queue. The EOObserverPriority
type's
constants are:
EOObserverPriorityImmediate | EOObserverPriorityFourth |
EOObserverPriorityFirst | EOObserverPriorityFifth |
EOObserverPrioritySecond | EOObserverPrioritySixth |
EOObserverPriorityThird | EOObserverPriorityLater |
EOObserver.h also defines the following int
constant
to identify the number of defined priorities (8 by default).
- ObserverNumberOfPriorities
Adopted Protocols
EOObserving
- - objectWillChange:
Method Types
- Change notification
- - subjectChanged
- Canceling change notification
- - discardPendingNotification
- Getting the queue and priority
- - observerQueue
- - priority
Instance Methods
discardPendingNotification
- (void)discardPendingNotification
See Also: - observerQueue
objectWillChange:
- (void)objectWillChange:(id)anObject
See Also: - observerQueue, - enqueueObserver: (EODelayedObserverQueue), objectWillChange: (EOObserving)
observerQueue
- (EODelayedObserverQueue *)observerQueue
See Also: defaultObserverQueue (EODelayedObserverQueue)
priority
- (EOObserverPriority)priority
- EOObserverPriorityImmediate
- EOObserverPriorityFirst
- EOObserverPrioritySecond
- EOObserverPriorityThird
- EOObserverPriorityFourth
- EOObserverPriorityFifth
- EOObserverPrioritySixth
- EOObserverPriorityLater
EODelayedObserver's
implementation returns EOObserverPriorityThird
.
See the EODelayedObserverQueue class specification for more information
on priorities.
subjectChanged
- (void)subjectChanged