PATH Documentation > WebObjects 4.5 > EOControl Reference

EODetailDataSource

Inherits from:
EODataSource
NSObject

Conforms to:
NSObject

(NSObject)

Declared in:
EOControl/EODetailDataSource.h

Class Description

EODetailDataSource defines a data source for use in master-detail configurations, where operations in the detail data source are applied directly to properties of a master object. EODetailDataSource implements the standard fetchObjects, insertObject:, and deleteObject: methods to operate on a relationship property of its master object, so it works for any concrete subclass of EODataSource, including another EODetailDataSource (for a chain of three master and detail data sources).

To set up an EODetailDataSource programmatically, you typically create it by sending a dataSourceQualifiedByKey: message to the master data source, then establish the master object with a qualifyWithRelationshipKey:ofObject: message. The latter method records the name of a relationship for a particular object to resolve in fetchObjects and to modify in insertObject:, and deleteObject:. These three methods then manipulate the relationship property of the master object to perform the operations requested. See the individual method descriptions for more information.

Method Types

Creating instances

- initWithMasterClassDescription:detailKey:

- initWithMasterDataSource:detailKey:

Qualifying instances

- qualifyWithRelationshipKey:ofObject:

Examining instances

- masterDataSource

- detailKey

- masterObject

Accessing the master class description

- masterClassDescription

- setMasterClassDescription:

Accessing the objects

- fetchObjects

Inserting and deleting objects

- insertObject:

- deleteObject:

Accessing the master editing context

- editingContext

Instance Methods

deleteObject:

- (void)deleteObject:(id)anObject

Sends a removeObject:fromPropertyWithKey: message (defined in the EORelationshipManipulation informal protocol) to the master object with anObject and the receiver's detail key as the arguments. Raises an NSInternalInconsistencyException if there's no master object or no detail key set.

detailKey

- (NSString *)detailKey

Returns the name of the relationship for which the receiver provides objects, as provided to initWithMasterDataSource:detailKey: or as set in qualifyWithRelationshipKey:ofObject:. If none has been set yet, returns nil.

editingContext

- (EOEditingContext *)editingContext

Returns the EOEditingContext of the master object, or nil if there isn't one.

fetchObjects

- (NSArray *)fetchObjects

Sends valueForKey: (defined in the EOKeyValueCoding informal protocol) to the master object with the receiver's detail key as the argument, constructs an array for the returned object or objects, and returns it. Returns an empty array if there's no master object, or returns an array containing the master object itself if no detail key is set.

initWithMasterClassDescription:detailKey:

- initWithMasterClassDescription:(EOClassDescription *)masterClassDescription detailKey:(NSString *)relationshipKey

Initializes a newly allocated EODetailDataSource to provide objects based on a relationship of objects in the master object associated with masterClassDescription. Invokes qualifyWithRelationshipKey:ofObject: with relationshipKey specified as the relationship key and nil specified as the object. The receiver initially has no master object selected; to select one, use qualifyWithRelationshipKey:ofObject:. This is the designated initializer for the EODetailDataSource class. Returns self.

See Also: - masterClassDescription, - detailKey

initWithMasterDataSource:detailKey:

- (id)initWithMasterDataSource:(EODataSource *)masterDataSource detailKey:(NSString *)relationshipKey

Initializes a newly allocated EODetailDataSource to provide objects based on a relationship of objects in masterDataSource named by relationshipKey. Invokes initWithMasterClassDescription:detailKey: with nil specified for the class description and relationshipKey specified as the detail key. The receiver initially has no master object selected; to select one, use qualifyWithRelationshipKey:ofObject:. Returns self.

See Also: - masterDataSource, - detailKey

insertObject:

- (void)insertObject:(id)anObject

Sends an addObject:toBothSidesOfRelationshipWithKey: message (defined in the EORelationshipManipulation informal protocol) to the master object with anObject and the receiver's detail key as the arguments. Raises an NSInternalInconsistencyException if there's no master object or no detail key set.

masterClassDescription

- (EOClassDescription *)masterClassDescription

Returns the EOClassDescription of the receiver's master object.

masterDataSource

- (EODataSource *)masterDataSource

Returns the receiver's master data source.

masterObject

- (id)masterObject

Returns the object in the master data source for which the receiver provides objects. You can change this with a qualifyWithRelationshipKey:ofObject: message.

See Also: - detailKey

qualifyWithRelationshipKey:ofObject:

- (void)qualifyWithRelationshipKey:(NSString *)relationshipKey ofObject:(id)masterObject

Configures the receiver to provide objects based on the relationship of masterObject named by relationshipKey. relationshipKey can be different from the one used with initWithMasterDataSource:detailKey:, which changes the relationship the receiver operates on. If masterObject is nil, this method causes the receiver to return an empty array when sent a fetchObjects message.

See Also: - detailKey

setMasterClassDescription:

- (void)setMasterClassDescription:(EOClassDescription *)classDescription

Assigns classDescription as the EOClassDescription for the receiver's master object.

See Also: - masterClassDescription