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Documentation > WebObjects 4.5 >
WebObjects Reference
Implemented by:
WODisplayGroup delegate objects
Package:
com.apple.yellow.webobjects
Interface Description
WODisplayGroup offers a number of methods for its delegate
to implement; if the delegate does implement them, the WODisplayGroup
instances invoke them as appropriate. There are methods that inform
the delegate that the EODisplayGroup 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 true to permit the action or false to
deny it. See each method's description for more information.
Instance Methods
public abstract void displayGroupCreateObjectFailedForDataSource(
WODisplayGroup aDisplayGroup,
Object aDataSource)
Invoked from insertNewObjectAtIndex 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
fails silently.
public abstract void displayGroupDidChangeDataSource(WODisplayGroup aDisplayGroup)
Informs the delegate that aDisplayGroup's
EODataSource (defined in the EOControl framework) has changed.
public abstract void displayGroupDidChangeSelectedObjects(WODisplayGroup aDisplayGroup)
Informs the delegate that aDisplayGroup's
selected objects have changed, regardless of whether the selection
indexes have changed.
public abstract void displayGroupDidChangeSelection(WODisplayGroup aDisplayGroup)
Informs the delegate that aDisplayGroup's
selection has changed.
public abstract void displayGroupDidDeleteObject(
WODisplayGroup aDisplayGroup,
Object anObject)
Informs the delegate that aDisplayGroup has
deleted anObject.
public abstract void displayGroupDidFetchObjects(
WODisplayGroup aDisplayGroup,
NSArray objects)
Informs the delegate that aDisplayGroup has
fetched objects.
public abstract void displayGroupDidInsertObject(
WODisplayGroup aDisplayGroup,
Object anObject)
Informs the delegate that aDisplayGroup has
inserted anObject.
public abstract void displayGroupDidSetValue(
WODisplayGroup aDisplayGroup,
Object value,
Object anObject,
String key)
Informs the delegate that aDisplayGroup has
altered a property value of anObject. key identifies
the property, and value is its new
value.
public abstract NSArray displayGroupDisplayArrayForObjects(
WODisplayGroup aDisplayGroup,
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, sortOrderings
public abstract boolean displayGroupShouldChangeSelectionToIndexes(
WODisplayGroup aDisplayGroup,
NSArray newIndexes)
Allows the delegate to prevent a change in selection
by aDisplayGroup. newIndexes is
the proposed new selection. If the delegate returns true, the selection
changes; if the delegate returns false, the selection remains as
it is.
public abstract boolean displayGroupShouldDeleteObject(
WODisplayGroup aDisplayGroup,
Object anObject)
Allows the delegate to prevent aDisplayGroup from
deleting anObject. If the delegate
returns true, anObject is deleted;
if the delegate returns false, the deletion is abandoned.
public abstract boolean displayGroupShouldFetch(WODisplayGroup aDisplayGroup)
Allows the delegate to prevent aDisplayGroup from
fetching. If the delegate returns true, aDisplayGroup performs
the fetch; if the delegate returns false, aDisplayGroup abandons
the fetch.
public abstract boolean displayGroupShouldInsertObject(
WODisplayGroup aDisplayGroup,
Object anObject,
int anIndex)
Allows the delegate to prevent redisplay from inserting anObject at anIndex.
If the delegate returns true, anObject is
inserted; if the delegate returns false, the insertion is abandoned.
public abstract boolean displayGroupShouldRedisplayForChangesInEditingContext(
WODisplayGroup aDisplayGroup,
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 true, aDisplayGroup redisplays;
if it returns false, aDisplayGroup doesn't.
See Also:
redisplay
public abstract boolean displayGroupShouldRefetchForInvalidatedAllObjects(
WODisplayGroup aDisplayGroup,
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 true, aDisplayGroup immediately
fetches its objects. If the delegate returns false, aDisplayGroup doesn't immediately
fetch, instead delaying until absolutely necessary.
See Also:
redisplay