Unable to use reference from a Make New command in Core-data app with AppleScript support - cocoa

Question

I am able to support the Make New command of AppleScript for my app, however the returned 'specified object' (an NSUniqueIDSpecifier) for the core data managed object is useless. The following AppleScript returns the error message:
error "SpellAnalysis got an error: Invalid key form." number -10002 from level id "x-coredata:///Levels/tC5A49E01-1CE1-4ED6-8F6B-BC0AE90E279A2"
tell application "SpellAnalysis"
set thisLevel to make new «class Slev» with properties {«class Saln»:3}
get properties of thisLevel
end tell
So the newly created Levels object can not be acted upon in AppleScript. I've combed the Web for a solution to this and the closest thing I have found is Bill Cheeseman's example app, "WareroomDemo" which specifically deals with Cocoa Scriptability for Core Data apps (the Sketch example does not use Core Data). Unfortunately, it is a dated example, running only on pre-64-bit XCode and I can't actually run it--I can only look at the code. His app's Make Command may have the same limitations for all I know.
The returned 'objectSpecifier' is unable to refer to the created object either as a safe-guard against corrupting Core Data's organizing scheme, or perhaps because the returned object is an un-cashed 'fault'. I think the latter possibility is unlikely because I can force the fault to cash (by getting a property value on the managed object) , yet I get the same error message with the AppleScript.
Here is the method that creates my class:
- (id)newScriptingObjectOfClass:(Class)class forValueForKey:(NSString *)key withContentsValue:(id)contentsValue properties:(NSDictionary *)properties { // Creates a new Lesson object in response to the AppleScript 'make' command.
// Documentation for 'newScriptingObject…' states that to create a new class object when using Core Data, you intercede using the following method (or you can subclass the NSCreateCommand's 'performDefaultImplementation' method and put your NSManagedObject init code there):
if (class == [Levels class]) {
//NSLog(#"class: %#",class);
NSEntityDescription *levelsEntity = [NSEntityDescription
entityForName:#"Levels"
inManagedObjectContext:levelsDBase];
NSManagedObject *levelObject = [[NSManagedObject alloc] initWithEntity:levelsEntity insertIntoManagedObjectContext:levelsDBase];
SLOG(#"lessonObject: %#", lessonObject);
NSString *levelNumberString = [[properties objectForKey:#"levelNumber"] stringValue];
SLOG(#"levelNumberString: %#", levelNumberString);
[levelObject setValue:levelNumberString forKey:#"levelNumber"];
return levelObject; // When using Core Data, it seems that you return the newly created object directly
}
return [super newScriptingObjectOfClass:(Class)class forValueForKey:(NSString *)key withContentsValue:(id)contentsValue properties:(NSDictionary *)properties];
}
Here is my object specifier method:
- (NSScriptObjectSpecifier *)objectSpecifier {
// This NSScriptObjectSpecifiers informal protocol returns a unique ID specifier specifying the absolute string of the URI representation of this managed object. // AppleScript return value: 'level id <id>'.
// The primary container is the application.
NSScriptObjectSpecifier *containerRef = nil; // I understand that if the application is the container, this is value you use for the container reference
NSString *uniqueID = [[[self objectID] URIRepresentation] absoluteString];
return [[[NSUniqueIDSpecifier alloc] initWithContainerClassDescription:[NSScriptClassDescription classDescriptionForClass:[NSApp class]] containerSpecifier:containerRef key:#"levelsArray" uniqueID:uniqueID] autorelease];
}

Answer 1

The problem lies with the specifier method. The Sketch example actually uses the technique that I needed. I overlooked it many times because I didn't see how it would apply to Core Data managed objects. Instead of returning the objects uniqueID, you make it return the managedObject index using the 'indexOfObjectIdenticalTo:' method as follows:
- (NSScriptObjectSpecifier *)objectSpecifier {
NSArray *levelsArray = [[NSApp delegate] levelsArray]; // Access your exposed to-many relationship--a mutable array
unsigned index = [levelsArray indexOfObjectIdenticalTo:self]; // Determin the current objects index
if (index != (unsigned)NSNotFound) {
// The primary container is the document containing this object's managed object context.
NSScriptObjectSpecifier *containerRef = nil; // the appliation
return [[[NSIndexSpecifier allocWithZone:[self zone]] initWithContainerClassDescription:[NSScriptClassDescription classDescriptionForClass:[NSApp class]] containerSpecifier:containerRef key:#"levelsArray" index:index] autorelease];
} else {
return nil;
}
}
Note that this method resides within a subclass of your Core Data managedObject--in this case, the 'Levels' class. The 'self' within the 'indexOfObjectIndenticalToSelf:' method refers to the current managedObject ('Levels') being handled. Also, be sure to provide the specifier (accessor) type to your 'sdef' file, like this:
<element type="level">
<cocoa key="levelsArray"/>
<accessor style="index"/>
</element>