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WODisplayGroup

Inherits from: NSObject

Conforms to: NSCoding
NSObject (NSObject)

Declared in: WebObjects/WODisplayGroup.h

Class Description

A WODisplayGroup is the basic user interface manager for a WebObjects application that accesses a database. It collects objects from an EODataSource (defined in EOControl), filters and sorts them, and maintains a selection in the filtered subset. You bind WebObjects dynamic elements to WODisplayGroup attributes and methods to display information from the database on your web page.

A WODisplayGroup manipulates its EODataSource by sending it fetchObjects, insertObject:, and other messages, and registers itself as an editor and message handler of the EODataSource's EOEditingContext (also defined in EOControl). The EOEditingContext then monitors the WODisplayGroup for changes to objects.

Most of a WODisplayGroup's interactions are with its EODataSource and its EOEditingContext. See the EODataSource, and EOEditingContext class specifications in the Enterprise Objects Framework Reference for more information on these interactions.

The Delegate

The WODisplayGroup delegate offers a number of methods, and WODisplayGroup invokes them as appropriate. Besides displayGroup:displayArrayForObjects:, there are methods that inform the delegate that the WODisplayGroup has fetched, created an object (or failed to create one), inserted or deleted an object, changed the selection, or set a value for a property. There are also methods that request permission from the delegate to perform most of these same actions. The delegate can return YES to permit the action or NO to deny it. See each method's description in the WODisplayGroup.Delegates protocol specification for more information.

Adopted Protocols

NSCoding
- encodeWithCoder:

- initWithCoder:

Method Types

Creating instances

- init

Configuring behavior

- setFetchesOnLoad:

- fetchesOnLoad

- setSelectsFirstObjectAfterFetch:

- selectsFirstObjectAfterFetch

+ setGlobalDefaultForValidatesChangesImmediately:

+ globalDefaultForValidatesChangesImmediately

- setValidatesChangesImmediately:

- validatesChangesImmediately

Setting the data source

- setDataSource:

- dataSource

Setting the qualifier and sort ordering

- setQualifier:

- qualifier

- setSortOrderings:

- sortOrderings

Managing queries

- qualifierFromQueryValues

- queryMatch

- queryMax

- queryMin

- queryOperator

- allQualifierOperators

- relationalQualifierOperators

- stringQualifierOperators

+ setGlobalDefaultStringMatchFormat:

+ globalDefaultStringMatchFormat

- setDefaultStringMatchFormat:

- defaultStringMatchFormat

+ setGlobalDefaultStringMatchOperator:

+ globalDefaultStringMatchOperator

- setDefaultStringMatchOperator:

- defaultStringMatchOperator

- qualifyDisplayGroup

- qualifyDataSource

- inQueryMode

- setInQueryMode:

Fetching objects from the data source

- fetch

Getting the objects

- allObjects

- displayedObjects

Batching the results

- setNumberOfObjectsPerBatch:

- numberOfObjectsPerBatch

- hasMultipleBatches

- displayNextBatch

- displayPreviousBatch

- batchCount

- setCurrentBatchIndex:

- currentBatchIndex

- indexOfFirstDisplayedObject

- indexOfLastDisplayedObject

- displayBatchContainingSelectedObject

Updating display of values

- redisplay

- updateDisplayedObjects

Setting the objects

- setObjectArray:

Changing the selection

- clearSelection

- selectNext

- selectObjectsIdenticalTo:

- selectObjectsIdenticalTo:selectFirstOnNoMatch:

- selectObject:

- selectPrevious

- setSelectedObject:

- setSelectedObjects:

- setSelectionIndexes:

Examining the selection

- selectionIndexes

- selectedObject

- selectedObjects

Inserting and deleting objects

- insertObject: atIndex:

- insertObjectAtIndex:

- insert

- setInsertedObjectDefaultValues:

- insertedObjectDefaultValues

- deleteObjectAtIndex:

- deleteSelection

- delete

Setting up a detail display group

- hasDetailDataSource

- setMasterObject:

- masterObject

- setDetailKey:

- detailKey

Working with named fetch specifications

- queryBindings

Setting the delegate

- setDelegate:

- delegate

Class Methods

globalDefaultForValidatesChangesImmediately

+ (BOOL)globalDefaultForValidatesChangesImmediately

Returns the class default controlling whether changes are immediately validated.

See Also: - validatesChangesImmediately

globalDefaultStringMatchFormat

+ (NSString *)globalDefaultStringMatchFormat

Returns the default string match format for the class.

See Also: - defaultStringMatchFormat

globalDefaultStringMatchOperator

+ (NSString *)globalDefaultStringMatchOperator

Returns the default string match operator for the class.

See Also: - defaultStringMatchOperator

setGlobalDefaultForValidatesChangesImmediately:

+ (void)setGlobalDefaultForValidatesChangesImmediately:(BOOL)flag

Sets according to flag the class default controlling whether changes are immediately validated.

setGlobalDefaultStringMatchFormat:

+ (void)setGlobalDefaultStringMatchFormat:(NSString *)format

Sets the default string match format for the class.

See Also: - setDefaultStringMatchFormat:

setGlobalDefaultStringMatchOperator:

+ (void)setGlobalDefaultStringMatchFormat:(NSString *)operator

Sets the default string match operator for the class.

See Also: - setDefaultStringMatchOperator:

Instance Methods

allObjects

- (NSArray *)allObjects

Returns all of the objects collected by the receiver.

See Also: - displayedObjects, - fetch

allQualifierOperators

- (NSArray *)allQualifierOperators

Returns an array containing all of the relational operators supported by EOControl's EOQualifier: =, !=, <, <=, >, >=, "like" and "caseInsensitiveLike".

batchCount

- (unsigned)batchCount

The number of batches to display. For example, if the displayed objects array contains two hundred records and the batch size is ten, batchCount returns twenty (twenty batches of ten records each).

clearSelection

- (BOOL)clearSelection

Invokes setSelectionIndexes: to clear the selection, returning YES on success and NO on failure.

currentBatchIndex

- (unsigned)currentBatchIndex

Returns the index of the batch currently being displayed. The total batch count equals the number of displayed objects divided by the batch size. For example, if the WODisplayGroup has one hundred objects to display and the batch size is twenty, there are five batches. The first batch has a batch index of 1.

dataSource

- (EODataSource *)dataSource

Returns the receiver's EODataSource (defined in the EOControl framework).

See Also: - hasDetailDataSource, - setDataSource:

defaultStringMatchFormat

- (NSString *)defaultStringMatchFormat

Returns the format string that specifies how pattern matching will be performed on string values in the queryMatch dictionary. If a key in the queryMatch dictionary does not have an associated operator in the queryOperator dictionary, then its value is matched using pattern matching, and the format string returned by this method specifies how it will be matched.

defaultStringMatchOperator

- (NSString *)defaultStringMatchOperator

Returns the operator used to perform pattern matching for string values in the queryMatch dictionary. If a key in the queryMatch dictionary does not have an associated operator in the queryOperator dictionary, then the operator returned by this method is used to perform pattern matching. Unless the default is changed, this method returns caseInsensitiveLike.

delegate

- (id)delegate

Returns the receiver's delegate.

See Also: - setDelegate:

delete

- (id)delete

Uses deleteSelection to attempt to delete the selected objects and then causes the page to reload. Returns nil to force reloading of the web page.

See Also: - deleteObjectAtIndex:

deleteObjectAtIndex:

- (BOOL)deleteObjectAtIndex:(unsigned)index

Attempts to delete the object at index, returning YES if successful and NO if not. Checks with the delegate using the method displayGroup:shouldDeleteObject:. If the delegate returns NO, this method fails and returns NO. If successful, it sends the delegate a displayGroup:didDeleteObject: message.

This method performs the delete by sending deleteObject to the EODataSource (defined in the EOControl framework). If that message raises an exception, this method fails and returns NO.

See Also: - delete, - deleteSelection

deleteSelection

- (BOOL)deleteSelection

Attempts to delete the selected objects, returning YES if successful and NO if not.

See Also: - delete, - deleteObjectAtIndex:

detailKey

- (NSString *)detailKey

For detail display groups, returns the key to the master object that specifies what this detail display group represents. That is, if you send the object returned by the masterObject method a valueForKey: message with this key, you obtain the objects controlled by this display group.

This method returns nil if the receiver is not a detail display group or if the detail key has not yet been set. You typically create a detail display group by dragging a to-many relationship from EOModeler to an open component in WebObjects Builder.

displayBatchContainingSelectedObject

- (id)displayBatchContainingSelectedObject

Displays the batch containing the selection and sets the current batch index to that batch's index. Returns nil to force the page to reload.

displayedObjects

- (NSArray *)displayedObjects

Returns the objects that should be displayed or otherwise made available to the user, as filtered by the receiver's delegate, by the receiver's qualifier and sort ordering.

If batching is in effect, displayedObjects returns the current batch of objects.

See Also: - allObjects, - updateDisplayedObjects, - qualifier, - setSortOrderings:, - displayGroup:displayArrayForObjects: (delegate method)

displayNextBatch

- (id)displayNextBatch

Increments the current batch index, displays that batch of objects, and clears the selection. If the batch currently being displayed is the last batch, this method displays the first batch of objects. Returns nil to force the page to reload.

displayPreviousBatch

- (id)displayPreviousBatch

Decrements the current batch index, displays that batch of objects, and clears the selection. If the batch currently being displayed is the first batch, this method displays the last batch of objects. Returns nil to force the page to reload.

fetch

- (id)fetch

Attempts to fetch objects from the EODataSource (defined in the EOControl framework).

Before fetching, this method sends displayGroupShouldFetch: to the delegate. If this method was successful, it then sends a fetchObjects message to the receiver's EODataSource to replace the object array, and if successful sends the delegate a displayGroup:didFetchObjects: message.

This method returns nil to force the page to reload.

See Also: - allObjects, - updateDisplayedObjects

fetchesOnLoad

- (BOOL)fetchesOnLoad

Returns YES if the receiver fetches automatically after the component that contains it is loaded, NO if it must be told explicitly to fetch. The default is YES. You can set this behavior in WebObjects Builder using the Display Group Options panel. Note that if the display group fetches on load, it performs the fetch each time the component is loaded into the web browser.

See Also: - fetch, - setFetchesOnLoad:

hasDetailDataSource

- (BOOL)hasDetailDataSource

Returns YES if the display group's data source is an EODetailDataSource (defined in the EOControl framework), and NO otherwise. If you drag a to-many relationship from EOModeler to an open component in WebObjects Builder, you create a display group that has an EODetailDataSource. You can also set this up using the Display Group Options panel in WebObjects Builder.

See Also: - detailKey, - masterObject

hasMultipleBatches

- (BOOL)hasMultipleBatches

Returns YES if the batch count is greater than 1. A display group displays its objects in batches if the numberOfObjectsPerBatch method returns a number that is less than the number of objects in the displayedObjects array.

indexOfFirstDisplayedObject

- (unsigned)indexOfFirstDisplayedObject

Returns the index of the first object displayed by the current batch. For example, if the current batch is displaying items 11 through 20, this method returns 11.

See Also: - indexOfLastDisplayedObject

indexOfLastDisplayedObject

- (unsigned)indexOfLastDisplayedObject

Returns the index of the last object display by the current batch. For example, if the current batch is displaying items 11 through 20, this method returns 20.

See Also: - indexOfFirstDisplayedObject

init

- (id)init

Initializes the WODisplayGroup. The WODisplayGroup then needs to have an EODataSource set with setDataSource:.

inQueryMode

- (BOOL)inQueryMode

Returns YES to indicate that the receiver is in query mode, NO otherwise. In query mode, controls in the user interface that normally display values become empty, allowing users to type queries directly into them (this is also known as a "Query by Example" interface). In effect, the receiver's "displayedObjects" are replaced with an empty queryMatch dictionary. When qualifyDisplayGroup or qualifyDataSource is subsequently invoked, the query is performed and the display reverts to displaying values-this time, the objects returned by the query.

See Also: - setInQueryMode:

insert

- (id)insert

Invokes insertObjectAtIndex: with an index just past the first index in the selection, or at the end if there's no selection.

This method returns nil to force the page to reload.

insertedObjectDefaultValues

- (NSDictionary *)insertedObjectDefaultValues

Returns the default values to be used for newly inserted objects. The keys into the dictionary are the properties of the entity that the display group manages. If the dictionary returned by this method is empty, the insert method adds an object that is initially empty. Because the object is empty, the display group has no value to display on the HTML page for that object, meaning that there is nothing for the user to select and modify. Use the setInsertedObjectDefaultValues: method to set up a default value so that there is something to display on the page.

insertObjectAtIndex:

- (id)insertObjectAtIndex:(unsigned)index

Asks the receiver's EODataSource (defined in the EOControl framework) to create a new object by sending it a createObject message, then inserts the new object using insertObject: atIndex:. If a new object can't be created, this method sends the delegate a displayGroup:createObjectFailedForDataSource: message.

If the object is successfully created, this method then sets the default values specified by insertedObjectDefaultValues.

See Also: - insert

insertObject: atIndex:

- (void)insertObject:(id)anObject atIndex:(unsigned)index

Inserts anObject into the receiver's EODataSource and displayed objects at the specified index, if possible. This method checks with the delegate before actually inserting, using displayGroup:shouldInsertObject:atIndex:. If the delegate refuses, anObject isn't inserted. After successfully inserting the object, this method informs the delegate with a displayGroup:didInsertObject: message, and selects the newly inserted object.

Raises an NSRangeException if index is out of bounds.

See Also: - insertObjectAtIndex:, - insert

masterObject

- (id)masterObject

Returns the master object for a detail display group (a display group that represents a detail in a master-detail relationship). A detail display group is one that uses an EODetailDataSource (defined in the EOControl framework). You create a detail display group by dragging a to-many relationship from EOModeler to an open component in WebObjects Builder. If the display group is not a detail display group or does not have a master object set, this method returns nil.

numberOfObjectsPerBatch

- (unsigned)numberOfObjectsPerBatch

Returns the batch size. You can set the batch size using setNumberOfObjectsPerBatch: or using WebObjects Builder's Display Group Options panel.

qualifier

- (EOQualifier *)qualifier

Returns the receiver's qualifier, which it uses to filter its array of objects for display when the delegate doesn't do so itself.

qualifierFromQueryValues

- (EOQualifier *)qualifierFromQueryValues

Builds a qualifier constructed from entries in these query dictionaries: queryMatch, queryMax, queryMin, and queryOperator.

qualifyDataSource

- (void)qualifyDataSource

Takes the result of qualifierFromQueryValues and applies to the receiver's data source. The receiver then sends itself a fetch message. If the receiver is in query mode, query mode is exited. This method differs from qualifyDisplayGroup as follows: whereas qualifyDisplayGroup performs in-memory filtering of already fetched objects, qualifyDataSource triggers a new qualified fetch against the database.

See Also: - queryMatch, - queryMax,, - queryMin, - queryOperator

qualifyDisplayGroup

- (void)qualifyDisplayGroup

Takes the result of the qualifierFromQueryValues and applies to the receiver using setQualifier:. The method updateDisplayedObjects is invoked to refresh the display. If the receiver is in query mode, query mode is exited.

queryBindings

- (NSMutableDictionary *)queryBindings

Returns a dictionary containing the actual values that the user wants to query upon. You use this method to perform a query stored in the model file. Bind keys in this dictionary to elements on your component that specify query values, then pass this dictionary to the fetch specification that performs the fetch.

queryMatch

- (NSMutableDictionary *)queryMatch

Returns a dictionary of query values to match. The qualifierFromQueryValues method uses this dictionary along with the queryMax and queryMin dictionaries to construct qualifiers.

Use the queryOperator dictionary to specify the type of matching (=, <, >, like, and so on) for each key in the queryMatch dictionary.

If the queryOperator dictionary does not contain a key contained in the queryMatch dictionary, the default is to match the value exactly (=) if the value is a number or a date and to perform pattern matching if the value is an NSString. In the case of string values, the defaultStringMatchFormat and defaultStringMatchOperator specify exactly how the pattern matching will be performed.

queryMax

- (NSMutableDictionary *)queryMax

Returns a dictionary of "less than" query values. The qualifierFromQueryValues method uses this dictionary along with the queryMatch and queryMin dictionaries to construct qualifiers.

queryMin

- (NSMutableDictionary *)queryMin

Returns a dictionary of "greater than" query values. The qualifierFromQueryValues method uses this dictionary along with the queryMatch and queryMin dictionaries to construct qualifiers.

queryOperator

- (NSMutableDictionary *)queryOperator

Returns a dictionary of operators to use on items in the queryMatch dictionary. If a key in the queryMatch dictionary also exists in queryOperator, that operator for that key is used. The allQualifierOperators method returns the operator strings you can use as values in this dictionary.

redisplay

- (void)redisplay

Sends out a contents changed notification.

relationalQualifierOperators

- (NSArray *)relationalQualifierOperators

Returns an array containing all of the relational operators supported by EOControl's EOQualifier: =, !=, <, <=, >, and >=. In other words, returns all of the EOQualifier operators except for the ones that work exclusively on strings: "like" and "caseInsensitiveLike".

selectedObject

- (id)selectedObject

Returns the first selected object in the displayed objects array, or nil if there's no such object.

selectedObjects

- (NSArray *)selectedObjects

Returns the objects selected in the receiver's displayed objects array.

selectionIndexes

- (NSArray *)selectionIndexes

Returns the selection as an array of NSNumbers. The NSNumbers are indexes into the array returned by displayedObjects.

selectNext

- (id)selectNext

Attempts to select the object just after the currently selected one. The selection is altered in this way:

If there are no objects, does nothing.
If there's no selection, selects the object at index zero.
If the first selected object is the last object in the displayed objects array, selects the first object.
Otherwise selects the object after the first selected object.

This method returns nil to force the page to reload.

selectObject:

- (BOOL)selectObject:(id)anObject

Attempts to select the object equal to anObject in the receiver's displayed objects array, returning YES if successful and NO otherwise. anObject is equal to an object in the displayed objects array if its address is the same as the object in the array.

See Also: - selectNext, - selectPrevious

selectObjectsIdenticalTo:

- (BOOL)selectObjectsIdenticalTo:(NSArray *)objectSelection

Attempts to select the objects in the receiver's displayed objects array whose ids are equal to those of objects, returning YES if successful and NO otherwise.

selectObjectsIdenticalTo:selectFirstOnNoMatch:

- (BOOL)selectObjectsIdenticalTo:(NSArray *)objects selectFirstOnNoMatch:(BOOL)flag

Selects the objects in the receiver's displayed objects array whose ids are equal to those of objects, returning YES if successful and NO otherwise. If no objects in the displayed objects array match objects and flag is YES, attempts to select the first object in the displayed objects array.

selectPrevious

- (id)selectPrevious

Attempts to select the object just before the presently selected one. The selection is altered in this way:

If there are no objects, does nothing.
If there's no selection, selects the object at index zero.
If the first selected object is at index zero, selects the last object.
Otherwise selects the object before the first selected object.

This method returns nil to force the page to reload.

See Also: - selectNext, - redisplay

selectsFirstObjectAfterFetch

- (BOOL)selectsFirstObjectAfterFetch

Returns YES YES if the receiver automatically selects its first displayed object after a fetch if there was no selection, NO if it leaves an empty selection as-is.

WODisplayGroups by default do select the first object after a fetch when there was no previous selection.

setCurrentBatchIndex:

- (void)setCurrentBatchIndex:(unsigned)anInt

Displays the anInt batch of objects. The total batch count equals the number of displayed objects divided by the batch size. For example, if the WODisplayGroup has one hundred objects to display and the batch size is twenty, there are five batches. The first batch has a batch index of 1. setCurrentBatchIndex:3 would display the third batch of objects (objects 41 to 60 in this example).

If anInt is greater than the number of batches, this method displays the first batch.

setDataSource:

- (void)setDataSource:(EODataSource *)aDataSource

Sets the receiver's EODataSource (defined in the EOControl framework) to aDataSource. In the process, it performs these actions:

Unregisters itself as an editor and message handler for the previous EODataSource's EOEditingContext (also defined in EOControl), if necessary, and registers itself with aDataSource's EOEditingContext. If the new EOEditingContext already has a message handler, however, the receiver doesn't assume that role.
Clears the receiver's array of objects.
Sends displayGroupDidChangeDataSource: to the delegate if there is one.

See Also: - dataSource

setDefaultStringMatchFormat:

- (void)setDefaultStringMatchFormat:(NSString *)format

Sets how pattern matching will be performed on NSString values in the queryMatch dictionary. This format is used for properties listed in the queryMatch dictionary that have NSString values and that do not have an associated entry in the queryOperator dictionary. In these cases, the value is matched using pattern matching and format specifies how it will be matched.

The default format string for pattern matching is "%@*" which means that the string value in the queryMatch dictionary is used as a prefix (this default can be overridden on a class basis using setGlobalDefaultStringMatchFormat:). For example, if the queryMatch dictionary contains a value "Jo" for the key "Name", the query returns all records whose name values begin with "Jo".

setDefaultStringMatchOperator:

- (void)setDefaultStringMatchOperator:(NSString *)operator

Sets the operator used to perform pattern matching for NSString values in the queryMatch dictionary. This operator is used for properties listed in the queryMatch dictionary that have NSString values and that do not have an associated entry in the queryOperator dictionary. In these cases, the operator operator is used to perform pattern matching.

The default value for the query match operator is caseInsensitiveLike, which means that the query does not consider case when matching letters (this default can be overridden on a class basis using setGlobalDefaultStringMatchOperator:). The other possible value for this operator is like, which matches the case of the letters exactly.

setDelegate:

- (void)setDelegate:(id)anObject

Sets the receiver's delegate to anObject, without retaining it.

See Also: - delegate, WODisplayGroup Delegate

setDetailKey:

- (void)setDetailKey:(NSString *)detailKey

Sets the detail key to detailKey for a detail display group. The detail key is the key that retrieves from the master object the objects that this display group manages. You must set a detail key before you set a master object.

If the receiver is not a detail display group, this method has no effect. A display group is a detail display group if its data source is an EODetailDataSource (defined in the EOControl framework). You typically create a detail display group by dragging a to-many relationship from EOModeler to an open component in WebObjects Builder. Doing so sets the detail key and master object, so you rarely need to use this method.

setFetchesOnLoad:

- (void)setFetchesOnLoad:(BOOL)flag

Controls whether the receiver automatically fetches its objects after being loaded. If flag is YES it does; if flag is NO the receiver must be told explicitly to fetch. The default is NO. You can also set this behavior in WebObjects Builder in the Display Group Options panel.

See Also: - fetch, - fetchesOnLoad

setInQueryMode:

- (void)setInQueryMode:(BOOL)flag

Sets according to flag whether the receiver is in query mode. In query mode, controls in the user interface that normally display values become empty, allowing users to type queries directly into them (this is also known as a "Query by Example" interface). In effect, the receiver's "displayedObjects" are replaced with an empty queryMatch dictionary. When qualifyDisplayGroup or qualifyDataSource is subsequently invoked, the query is performed and the display reverts to displaying values-this time, the objects returned by the query.

See Also: - inQueryMode

setInsertedObjectDefaultValues:

- (void)setInsertedObjectDefaultValues:(NSDictionary *)defaultValues

Sets default values to be used for newly inserted objects. When you use the insert method to add an object, that object is initially empty. Because the object is empty, there is no value to be displayed on the HTML page, meaning there is nothing for the user to select and modify. You use this method to provide at least one field that can be displayed for the newly inserted object. The possible keys into the dictionary are the properties of the entity managed by this display group. For example, a component that displays a list of movie titles and allows the user to insert new movie titles might contain these statements to ensure that all new objects have something to display as a movie title:

[defaultValues setObject:@"New title" forKey:@"title"];
[movies setInsertedObjectDefaultValues:defaultValues];

See Also: - insertedObjectDefaultValues

setMasterObject:

- (void)setMasterObject:(id)masterObject

Sets the master object to masterObject for detail display groups and then performs a fetch if the display group is set to fetch on load. The master object owns the objects controlled by this display group.

Before you use this method, you should use the setDetailKey: to set the key to this relationship. You typically create a detail display group by dragging a to-Many relationship from EOModeler to an open component in WebObjects Builder. Doing so sets the master object and detail key, so you typically do not have to use this method.

If the receiver is not a detail display group, this method has no effect.

See Also: - hasDetailDataSource, - masterObject

setNumberOfObjectsPerBatch:

- (void)setNumberOfObjectsPerBatch:(unsigned)count

Sets the number of objects the receiver displays at a time. For example, suppose you are displaying one hundred records. Instead of displaying all of these at once, you can set the batch size so that the page displays a more manageable number (for example, 10). WebObjects Builder allows you to set the number of objects per batch on the Display Group Options panel.

setObjectArray:

- (void)setObjectArray:(NSArray *)objects

Sets the receiver's objects to objects, regardless of what its EODataSource (defined in the EOControl framework) provides. This method doesn't affect the EODataSource's objects at all; specifically, it results in neither inserts nor deletes of objects in the EODataSource. objects should contain objects with the same property names or methods as those accessed by the receiver. This method is used by fetch to set the array of fetched objects; you should rarely need to invoke it directly.

After setting the object array, this method restores as much of the original selection as possible. If there's no match and the receiver selects after fetching, then the first object is selected.

setQualifier:

- (void)setQualifier:(EOQualifier *)aQualifier

Sets the receiver's qualifier to aQualifier. This qualifier is used to filter the receiver's array of objects for display. Use updateDisplayedObjects to apply the qualifier.

If the receiver's delegate responds to displayGroup:displayArrayForObjects:, that method is used instead of the qualifier to filter the objects.

See Also: - displayedObjects, - qualifier

setSelectedObject:

- (void)setSelectedObject:(id)anObject

Sets the first selected object in the displayed objects array to anObject.

setSelectedObjects:

- (void)selectedObjects:(NSArray *)objects

Sets the objects selected in the receiver's displayed objects array to objects.

setSelectionIndexes:

- (BOOL)setSelectionIndexes:(NSArray *)selection

Selects the objects at selection in the receiver's array if possible, returning YES if successful and NO if not (in which case the selection remains unaltered). This method is the primitive method for altering the selection; all other such methods invoke this one to make the change.

This method checks the delegate with a displayGroup:shouldChangeSelectionToIndexes: message. If the delegate returns NO, this method also fails and returns NO. If the receiver successfully changes the selection, its observers each receive a displayGroupDidChangeSelection: message and, if necessary, a displayGroupDidChangeSelectedObjects: message.

See Also: - allObjects

setSelectsFirstObjectAfterFetch:

- (void)setSelectsFirstObjectAfterFetch:(BOOL)flag

Controls whether the receiver automatically selects its first displayed object after a fetch when there were no selected objects before the fetch. If flag is YES it does; if flag is NO then no objects are selected.

WODisplayGroups by default do select the first object after a fetch when there was no previous selection.

setSortOrderings:

- (void)setSortOrderings:(NSArray *)keySortOrderArray

Sets the EOSortOrdering objects (defined in the EOControl framework) that updateDisplayedObjects uses to sort the displayed objects to orderings. Use updateDisplayedObjects to apply the sort orderings.You can also set this value using the WebObjects Builder Display Group Options panel.

If the receiver's delegate responds to displayGroup:displayArrayForObjects:, that method is used instead of the sort orderings to order the objects.

setValidatesChangesImmediately:

- (void)setValidatesChangesImmediately:(BOOL)flag

Controls the receiver's behavior on encountering a validation error. In the Web context, this method has no effect.

WODisplayGroups by default don't validate changes immediately (although this default can be overridden on a class basis; see setGlobalDefaultForValidatesChangesImmediately:).

See Also: - saveChanges (in EOControl's EOEditingContext), - tryToSaveChanges (EOEditingContext Additions), - validatesChangesImmediately, + setGlobalDefaultForValidatesChangesImmediately:

sortOrderings

- (NSArray *)sortOrderings

Returns an array of EOSortOrdering objects (defined in the EOControl framework) that updateDisplayedObjects uses to sort the displayed objects, as returned by the displayedObjects method.

See Also: - setSortOrderings:

stringQualifierOperators

- (NSArray *)stringQualifierOperators

Returns an array containing all of the relational operators supported by EOControl's EOQualifier that work exclusively on strings: "starts with", "contains", "ends with", "is", and "like".

updateDisplayedObjects

- (void)updateDisplayedObjects

Recalculates the receiver's displayed objects arrays and redisplays. If the delegate responds to displayGroup:displayArrayForObjects:, it's sent this message and the returned array is set as the WODisplayGroup's displayed objects. Otherwise, the receiver applies its qualifier and sort ordering to its array of objects. In either case, any objects that were selected before remain selected in the new displayed object's array.

validatesChangesImmediately

- (BOOL)validatesChangesImmediately

Returns YES if the receiver immediately handles validation errors, or leaves them for the EOEditingContext (defined in the EOControl framework) to handle when saving changes.

By default, WODisplayGroups don't validate changes immediately.

The selection set here is only a programmatic selection; the objects on the screen are not highlighted in any way.