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 Yellow Box 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
The following integer constants are defined to represent the priority of a notification in the queue:
EOObserverPriorityImmediate | EOObserverPriorityFourth |
EOObserverPriorityFirst | EOObserverPriorityFifth |
EOObserverPrioritySecond | EOObserverPrioritySixth |
EOObserverPriorityThird | EOObserverPriorityLater |
Adopted Protocols
- EOObserving
- - objectWillChange:
Method Types
- Change notification
- - subjectChanged
- Canceling change notification
- - discardPendingNotification
- Getting the queue and priority
- - observerQueue
- - priority
Instance Methods
discardPendingNotification
- (void)discardPendingNotificationSends a dequeueObserver: message to the receiver's EODelayedObserverQueue to clear it from receiving a change notification. A subclass of EODelayedObserver should invoke this method in its implementation of dealloc .
See also: observerQueue
objectWillChange:
@protocol EOObserving
- (void)objectWillChange: (id)anObject
Implemented by EODelayedObserver to enqueue the receiver on its EODelayedObserverQueue. Subclasses shouldn't need to override this method; if they do, they must be sure to invoke super 's implementation.
See also: observerQueue , - enqueueObserver: (EODelayedObserverQueue), objectWillChange: (EOObserving)
observerQueue
- (EODelayedObserverQueue *)observerQueue
Overridden by subclasses to return the receiver's designated EODelayedObserverQueue. EODelayedObserver's implementation returns the default EODelayedObserverQueue.
See also: defaultObserverQueue (EODelayedObserverQueue)
priority
- (EOObserverPriority)priority
Overridden by subclasses to return the receiver's change notification priority, one of:
- 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
Implemented by subclasses to examine the receiver's observed objects and take whatever action is necessary. EODelayedObserver's implementation does nothing.
Copyright © 1998, Apple Computer, Inc. All rights reserved.