Class WODisplayGroup

Inherits From:
NSObject
Adopts:
NSCoding


CLASS AT A GLANCE

Purpose

A WODisplayGroup collects an array of objects from an EODataSource and displays and edits properties of those objects.

Principal Attributes

Creation

Through Project Builder Wizard or WebObjects Builder and EOModeler
init

Commonly Used Methods

allObjects Returns all objects in the WODisplayGroup.
displayedObjectsReturns the subset of all objects made available for display.
selectedObjectsReturns the selected objects.
setQualifier:Sets a filter that limits the objects displayed.
setSortOrdering:Sets the ordering used to sort the objects.
updateDisplayedObjectsFilters, sorts, and redisplays the objects
insertCreates a new object and inserts it into the EODataSource.

CLASS DESCRIPTION

A WODisplayGroup is the basic user interface manager for a WebObjects application that accesses a database. It collects objects from an EODataSource, 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. 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 Frameworks Reference for more information on these interactions.

Creating a WODisplayGroup

You create most WODisplayGroups in one of these ways:

Most WODisplayGroups operate independently of other WODisplayGroups; however, you can set up a master-detail association between two WODisplayGroups. You typically do this by dragging a to-many relationship from the EOModeler application to a component opened in the WebObjects Builder application. When you do this, the display group you create has an EODetailDataSource as its data source, a detail key equal to the to-many relationship's key, and a master object equal to the entity from which you dragged the relationship.

To create a WODisplayGroup programmatically, simply initialize it and set its EODataSource:

EODataSource *myDataSource;    /* Assume this exists. */

WODisplayGroup *myDisplayGroup;



myDisplayGroup = [[[WODisplayGroup] alloc] init] autorelease];

[myDisplayGroup setDataSource:myDataSource];

Getting Objects

Since a WODisplayGroup isn't much use without objects to manage, the first thing you do with a WODisplayGroup is send it a fetch message. You can use the basic fetch method, or you can configure the WODisplayGroup in WebObjects Builder to fetch automatically when its component is loaded. The fetch method asks the WODisplayGroup's EODataSource to fetch from its persistent store with a fetchObjects message.

Filtering and Sorting

A WODisplayGroup's fetched objects are available through its allObjects method. These objects are treated only as candidates for display, however. The array of objects actually displayed is filtered and sorted by the WODisplayGroup's delegate or by a qualifier and a sort ordering array. You set the qualifier and sort orderings using the setQualifier: and setSortOrdering: methods. The displayedObjects method returns this filtered and sorted array; index arguments to other WODisplayGroup methods are defined in terms of this array.

If the WODisplayGroup has a delegate that responds to displayGroup:displayArrayForObjects:, it invokes this method rather than using its own qualifier and sort ordering array. The delegate is then responsible for filtering the objects and returning a sorted array. If the delegate only needs to perform one of these steps, it can get the qualifier or sort orderings from the WODisplayGroup and apply either itself using the NSArray methods filteredArrayUsingQualifier: and sortedArrayUsingKeyOrderingArray:.

If you change the qualifier or sort ordering, or alter the delegate in a way that changes how it filters and sorts the WODisplayGroup's objects, you can send updateDisplayedObjects to the WODisplayGroup to get it to refilter and resort its objects. Note that this doesn't cause the WODisplayGroup to refetch.

Batching the Output

Even after the output has been qualified and sorted, there might be too many objects to display on a single HTML page. For this reason and to improve your application's performance, WODisplayGroup supports batching the display. When batching is used, the HTML page shows only a certain number of objects at a time. If you create the WODisplayGroup using Project Builder's Wizard, the default batch size is 10. Thus if there are one hundred objects to display, displayedObjects returns only the first ten of those objects when the page is drawn. If displayNextBatch is invoked, displayedObjects is updated to contain the next ten objects, and the page is redrawn.

You use displayNextBatch and displayPreviousBatch to move back and forth through the displayed objects. The setNumberOfObjectsPerBatch: method changes the batch size. You can also change batch size using WebObjects Builder.

Changing and Examining the Selection

A WODisplayGroup keeps a selection in terms of indexes into the array of displayed objects. Components that display values for multiple objects are responsible for updating the selection in their WODisplayGroups according to user actions on their dynamic elements. This is typically done with the setSelectionIndexes: method. Other methods available for indirect manipulation of the selection are the action methods selectNext and selectPrevious.

To get the selection, you can use the selectionIndexes method, which returns an array of indexes (as NSNumber objects), or selectedObjects, which returns an array containing the selected objects themselves. Another method, selectedObject, returns the first selected object if there is one.

Note: The selection is a programmatical selection only. The selected objects don't actually appear highlighted on the web page.

The Delegate

The WODisplayGroup delegate offers a number of methods, and WODisplayGroup invokes them as appropriate. Besides the aforementioned 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 Methods Implemented by the Delegate section for more information.

Performing Queries

If you are building a component that allows users to perform database queries, you use a WODisplayGroup to construct a qualifier that reflects the query.

To construct a qualifier, you bind dynamic elements in your component to keys in the queryMatch, queryMax, or queryMin dictionaries. The possible keys to these dictionaries are the properties of the entity managed by the WODisplayGroup.

For simple queries, the queryMatch dictionary is often sufficient. The associated queryOperator dictionary tells how to match the values in queryMatch. When a qualifier is constructed from queryMatch, it works this way:

Tip: To ensure that value types are interpreted appropriately, use formatters on the WOTextField. That is, if the value is a number, use WOTextField's numberformat attribute to specify how the number should appear. If the value is a date, use the dateformat attribute.

Tip: You might find it convenient to use the array returned by allQualifierOperators as input to a WOPopUpButton element so that your users can choose how they want the matching to be performed.

To perform from-to queries, you can use queryMax and queryMin. For example, suppose you had a Movies database and wanted to build a query to return all movies released between two dates: January 1, 1994 and December 31, 1994. queryMax would contain one key, dateReleased, with the value December 31, 1994, and queryMin would contain the same key with the value January 1, 1994.

After you've provided the values for the query, you build the qualifier and perform the fetches using one of two methods: qualifyDataSource or qualifyDisplayGroup. qualifyDataSource fetches the items directly from the database. qualifyDisplayGroup filters the objects in memory after they are fetched. Both use qualifierFromQueryValues to construct the qualifier used to perform the fetch.


INSTANCE METHODS

allObjects

- (NSArray *)allObjects

Returns all of the objects collected by the receiver.

See Also: - displayedObjects, - fetch


allQualifierOperators

- (NSArray *) allQualifierOperators

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

See Also: - queryOperator, - relationalQualifierOperators


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).

See Also: - currentBatchIndex, - displayNextBatch, - displayPreviousBatch, - hasMultipleBatches, - numberOfObjectsPerBatch


buildsQualifierFromInput

- (BOOL)buildsQualifierFromInput

Returns YES if the receiver performs database fetches using the executeQuery method.

This method is provided for backwards compatibility only. For WebObjects 3.5 and above you should use the queryMatch, queryMax, and queryMin methods to construct queries.


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.

See Also: - batchCount, - numberOfObjectsPerBatch, - setCurrentBatchIndex:


dataSource

- (EODataSource *)dataSource

Returns the receiver's EODataSource.

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.

See Also: - defaultStringMatchOperator, - setDefaultStringMatchFormat:


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.

See Also: - defaultStringMatchFormat, - setDefaultStringMatchOperator:


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. 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.

See Also: - hasDetailDataSource, - masterObject, - setDetailKey:


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.

See Also: - displayNextBatch, - displayPreviousBatch, - setCurrentBatchIndex:


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, - sortOrdering, - 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.

See Also: - batchCount, - currentBatchIndex, - displayBatchContainingSelectedObject, - displayPreviousBatch


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.

See Also: - batchCount, - currentBatchIndex, - displayBatchContainingSelectedObject, - displayNextBatch


endEditing

- (BOOL)endEditing

Ends any editing taking place and returns YES.


executeQuery

- (id)executeQuery

Builds a qualifier using qualifierFromInputValues and then fetches the objects that match that qualifier. The WODisplayGroup's qualifier is set to nil at the end of this method so that subsequent updateDisplayedObjects messages only apply the sort ordering.

This method is provided for backwards compatibility only. For WebObjects 3.5 and above you should use the qualifyDataSource or qualifyDisplayGroup methods to perform queries.


fetch

- (id)fetch

Attempts to fetch objects from the EODataSource.

Before fetching, invokes endEditing and sends displayGroupShouldFetch: to the delegate. If both of those methods were 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 being 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.

See Also: - fetch, - setFetchesOnLoad:


hasDetailDataSource

- (BOOL)hasDetailDataSource

Returns YES if the display group's data source is an EODetailDataSource, 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.

See Also: - batchCount, - setNumberOfObjectsPerBatch:


init

- (id)init

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


inputObjectForQualifier

- (NSMutableDictionary *)inputObjectForQualifier

Returns an NSMutableDictionary that is used by qualifierFromInputValues to build a qualifier.

This method is provided for backwards compatibility only. For WebObjects 3.5 and above you should use the queryMatch, queryMax, and queryMin methods to construct queries.


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 0 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.


insertObject:atIndex:

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

Inserts anObject into the receiver's EODataSource and displayed objects at 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


insertObjectAtIndex:

- (id)insertObjectAtIndex:(unsigned)anIndex

Asks the receiver's EODataSource 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


lastQualifierFromInputValues

- (EOQualifier *)lastQualifierFromInputValues

If qualifierFromInputValues has previously been invoked to construct a qualifier, this method returns the qualifier that that method built. If qualifierFromInputValues has not been used, this method return nil.

This method is provided for backwards compatibility only. For WebObjects 3.5 and above, the qualifierFromQueryValues performs a similar function.


localKeys

- (NSArray *)localKeys

Returns the additional keys that dynamic elements can be bound to. A WODisplayGroup's basic keys are typically those of the attributes and relationships of its objects, as defined by their class descriptions through an entity in the model. Local keys are typically used to form associations with key paths, with arbitrary methods of objects, or with properties of objects not associated with an entity.

See Also: - setLocalKeys:


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. 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.

See Also: - detailKey - hasDetailDataSource, - setMasterObject:


numberOfObjectsPerBatch

- (unsigned)numberOfObjectsPerBatch

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

See Also: - setNumberOfObjectsPerBatch:


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.

See Also: - displayedObjects, - setQualifier:, - updateDisplayedObjects


qualifierFromInputValues

- (EOQualifier *)qualifierFromInputValues

Builds a qualifier from the dictionaries returned by inputObjectForQualifier and secondObjectForQualifier. This qualifier is used by the executeQuery method to fetch records from the database.

This method is provided for backwards compatibility only. For WebObjects 3.5 and above, the method qualifierFromQueryValues performs a similar function.


qualifierFromQueryValues

- (EOQualifier *)qualifierFromQueryValues

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

See Also: - qualifyDataSource, - qualifyDisplayGroup


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.

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


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.

See Also: - allQualifierOperators, - qualifyDataSource, - qualifyDisplayGroup, - relationalQualifierOperators


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.

See Also: - qualifyDataSource, - qualifyDisplayGroup, - queryOperator


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.

See Also: - qualifyDataSource, - qualifyDisplayGroup, - queryOperator


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.

See Also: - qualifierFromQueryValues, - queryMax - queryMin, - relationalQualifierOperators


redisplay

- (void)redisplay

Sends out a contents changed notification.


relationalQualifierOperators

- (void)relationalQualifierOperators

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

See Also: - allQualifierOperators, - queryOperator


secondObjectForQualifier

- (NSMutableDictionary *)secondObjectForQualifier

Returns a mutable dictionary that specifies the "to" value in from-to queries. This method is used by the qualifierFromInputValues method to build a qualifier.

This method is provided for backwards compatibility only. For WebObjects 3.5 and above you should use the queryMatch, queryMax, and queryMin methods to construct queries.


selectedObject

- (id)selectedObject

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

See Also: - displayedObjects, - selectionIndexes, - selectedObjects


selectedObjects

- (NSArray *)selectedObjects

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

See Also: - displayedObjects, - selectionIndexes, - selectedObject


selectionIndexes

- (NSArray *)selectionIndexes

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

See Also: - selectedObject, - selectedObjects, - setSelectionIndexes:


selectNext

- (id)selectNext

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

This method returns nil to force the page to reload.

See Also: - selectPrevious, - setSelectionIndexes:


selectObject:

- (BOOL)selectObject:(id)object

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 *)objects

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.

See Also: - setSelectionIndexes:, - selectObjectsIdenticalTo:selectFirstOnNoMatch:


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.

See Also: - setSelectionIndexes:, - selectObjectsIdenticalTo:


selectPrevious

- (id)selectPrevious

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

This method returns nil to force the page to reload.

See Also: - selectNext, - redisplay


selectsFirstObjectAfterFetch

- (BOOL)selectsFirstObjectAfterFetch

Returns 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.

See Also: - displayedObjects, - fetch, - setSelectsFirstObjectAfterFetch:


setBuildsQualifierFromInput:

- (void)setBuildsQualifierFromInput:(BOOL)flag

Sets whether the receiver should build a qualifier before fetching. If flag is YES, the receiver should perform database fetches using the executeQuery method, which first builds a qualifier using the method qualifierFromInputValues and then performs the fetch.

This method is provided for backwards compatibility only. For WebObjects 3.5 and above you should use the queryMatch, queryMax, and queryMin methods to construct queries.


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.

See Also: - batchCount, - currentBatchIndex, - displayBatchContainingSelectedObject, - displayNextBatch, - displayPreviousBatch, - numberOfObjectsPerBatch


setDataSource:

- (void)setDataSource:(EODataSource *)aDataSource

Sets the receiver's EODataSource to aDataSource. In the process, it performs these actions:

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. 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".

See Also: - defaultStringMatchFormat, - setDefaultStringMatchOperator:


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. The other possible value for this operator is like, which matches the case of the letters exactly.

See Also: - allQualifierOperators, - defaultStringMatchOperator, - relationalQualifierOperators, - setDefaultStringMatchFormat:


setDelegate:

- (void)setDelegate:(id)anObject

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

See Also: - delegate, Methods Implemented by the 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. 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.

See Also: - hasDetailDataSource, - detailKey, - setMasterObject:


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


setLocalKeys:

- (void)setLocalKeys:(NSArray *)keys

Sets the additional keys to which dynamic elements can be bound to keys.

See Also: - localKeys


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.

See Also: - batchCount, - displayNextBatch, - displayPreviousBatch, - numberOfObjectsPerBatch


setObjectArray:

- (void)setObjectArray:(NSArray *)objects

Sets the receiver's objects to objects, regardless of what its EODataSource 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.

See Also: - allObjects, - displayedObjects, - fetch, - selectsFirstObjectAfterFetch


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


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 invokes endEditing to wrap up any changes being made by the user. If endEditing returns NO, this method fails and returns NO. This method then 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.

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

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.

See Also: - displayedObjects, - fetch, - selectsFirstObjectAfterFetch


setSortOrdering:

- (void)setSortOrdering:(NSArray *)orderings

Sets the EOSortOrdering objects 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.

See Also: - displayedObjects, - sortOrdering, - updateDisplayedObjects


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.

See Also: - saveChanges (in EOEditingContext), - validatesChangesImmediately


sortOrdering

- (NSArray *)sortOrdering

Returns an array of EOSortOrdering objects that updateDisplayedObjects uses to sort the displayed objects, as returned by the displayedObjects method.

See Also: - setSortOrdering:


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.

See Also: - redisplay, - allObjects, - displayedObjects, - qualifier, - selectedObjects, - sortOrdering


validatesChangesImmediately

- (BOOL)validatesChangesImmediately

Returns YES if the receiver immediately handles validation errors, or leaves them for the EOEditingContext to handle when saving changes.

By default, WODisplayGroups don't validate changes immediately.

See Also: - setValidatesChangesImmediately:


METHODS IMPLEMENTED BY THE DELEGATE

displayGroup:createObjectFailedForDataSource:

- (void)displayGroup:(WODisplayGroup *)aDisplayGroup createObjectFailedForDataSource:aDataSource

Invoked from insertObjectAtIndex: to inform the delegate that aDisplayGroup has failed to create a new object for aDataSource. If the delegate doesn't implement this method, the WODisplayGroup instead fails silently.


displayGroup:didDeleteObject:

- (void)displayGroup:(WODisplayGroup *)aDisplayGroup didDeleteObject:anObject

Informs the delegate that aDisplayGroup has deleted anObject.


displayGroup:didFetchObjects:

- (void)displayGroup:(WODisplayGroup *)aDisplayGroup didFetchObjects:(NSArray *)objects

Informs the delegate that aDisplayGroup has fetched objects.


displayGroup:didInsertObject:

- (void)displayGroup:(WODisplayGroup *)aDisplayGroup didInsertObject:anObject

Informs the delegate that aDisplayGroup has inserted anObject.


displayGroup:didSetValue:forObject:key:

- (void)displayGroup:(WODisplayGroup *)aDisplayGroup didSetValue:(id)value forObject:(id)anObject key:(NSString *)key

Informs the delegate that aDisplayGroup has altered a property value of anObject. key identifies the property, and value is its new value.


displayGroup:displayArrayForObjects:

- (NSArray *)displayGroup:(WODisplayGroup *)aDisplayGroup displayArrayForObjects:(NSArray *)objects

Invoked from updateDisplayedObjects, this method allows the delegate to filter and sort aDisplayGroup's array of objects to limit which ones get displayed. objects contains all of aDisplayGroup's objects. The delegate should filter any objects that shouldn't be shown and sort the remainder, returning a new array containing this group of objects. You can use the NSArray methods filteredArrayUsingQualifier: and sortedArrayUsingKeyOrderingArray: to create the new array.

If the delegate doesn't implement this method, the WODisplayGroup uses its own qualifier and sort ordering to update the displayed objects array.

See Also: - displayedObjects, - qualifier, - sortOrdering


displayGroup:shouldChangeSelectionToIndexes:

- (BOOL)displayGroup:(WODisplayGroup *)aDisplayGroup shouldChangeSelectionToIndexes:(NSArray *)newIndexes

Allows the delegate to prevent a change in selection by aDisplayGroup. newIndexes is the proposed new selection. If the delegate returns YES, the selection changes; if the delegate returns NO, the selection remains as it is.


displayGroup:shouldDeleteObject:

displayGroup:(WODisplayGroup *)aDisplayGroup shouldDeleteObject: anObject

Allows the delegate to prevent aDisplayGroup from deleting anObject. If the delegate returns YES, anObject is deleted; if the delegate returns NO, the deletion is abandoned.


displayGroup:shouldInsertObject:atIndex:

- (BOOL)displayGroup:(WODisplayGroup *)aDisplayGroup shouldInsertObject:anObject atIndex:(unsigned)anIndex

Allows the delegate to prevent aDisplayGroup from inserting anObject at anIndex. If the delegate returns YES, anObject is inserted; if the delegate returns NO, the insertion is abandoned.


displayGroup:shouldRedisplayForEditingContextChangeNotification:

- (BOOL)displayGroup:(WODisplayGroup *)aDisplayGroup shouldRedisplayForEditingContextChangeNotification:(NSNotification *)aNotification

Invoked whenever aDisplayGroup receives an EOObjectsChangedInEditingContextNotification, this method allows the delegate to suppress redisplay based on the nature of the change that has occurred. If the delegate returns YES, aDisplayGroup redisplays; if it returns NO, aDisplayGroup doesn't.

See Also: - redisplay


displayGroup:shouldRefetchForInvalidatedAllObjectsNotification:

- (BOOL)displayGroup:(WODisplayGroup *)aDisplayGroup shouldRefetchForInvalidatedAllObjectsNotification:(NSNotification *)aNotification

Invoked whenever aDisplayGroup receives an EOInvalidatedAllObjectsInStoreNotification, this method allows the delegate to suppress the refetching of the invalidated objects. If the delegate returns YES, aDisplayGroup immediately fetches its objects. If the delegate returns NO, aDisplayGroup doesn't immediately fetch, instead delaying until absolutely necessary.

See Also: - redisplay


displayGroupDidChangeDataSource:

- (void)displayGroupDidChangeDataSource:(WODisplayGroup *)aDisplayGroup

Informs the delegate that aDisplayGroup's EODataSource has changed.


displayGroupDidChangeSelectedObjects:

- (void)displayGroupDidChangeSelectedObjects:(WODisplayGroup *)aDisplayGroup

Informs the delegate that aDisplayGroup's selected objects have changed, regardless of whether the selection indexes have changed.


displayGroupDidChangeSelection:

- (void)displayGroupDidChangeSelection:(WODisplayGroup *)aDisplayGroup

Informs the delegate that aDisplayGroup's selection has changed.


displayGroupShouldFetch:

- (BOOL)displayGroupShouldFetch:(WODisplayGroup *)aDisplayGroup

Allows the delegate to prevent aDisplayGroup from fetching. If the delegate returns YES, aDisplayGroup performs the fetch; if the delegate returns NO, aDisplayGroup abandons the fetch.