CoreDataObjectIDTransformer.h

//
//  CoreDataObjectIDTransformer.h
//  Add Folder Icons
//
//  Created by Andrew Hodgkinson on 21/01/2011.
//  Copyright 2011 Hipposoft. All rights reserved.
//
//  Converts from a ManagedObjectID to an NSString and vice versa.
//
//  A persistent store coordinator reference MUST be supplied before the
//  transformer will work. See "-setPersistentStoreCoordinator:"
//  (synthesized). Without this, forwards transformation will always result
//  in a result of 'nil'.
//
//  This value transformer is intended to be used with pop-up menus bound to
//  an array controller managing a CoreData collection of icon styles. The
//  content should be bound to the controller's arranged objects (no key path),
//  the content objects be bound to the "objectID" key path and the content
//  values be bound to the "name" key path. Thus the menu displays style names
//  but records unique CoreData object IDs internally.
// 
//  If the result of the selection needs to be stored in e.g. a preferences
//  file, the menu's selected object is bound to e.g. the shared user defaults
//  controller for whatever key path is to be used to record the selection in
//  the preferences (e.g. "defaultStyle" to store a chosen default icon style).
//  However, this would fail because only easily serialised data such as an
//  NSString can be written to a property list without a value transformer.
// 
//  Thus, specify "CoreDataObjectIDTransformer" as a value transformer for
//  the content objects binding of the menu. Specify the same as a value
//  transformer for the selected object binding. The transformer takes the
//  object ID and turns it into an NSString or vice versa.
//

#import <Cocoa/Cocoa.h>

@interface CoreDataObjectIDTransformer : NSValueTransformer
{
    NSPersistentStoreCoordinator * persistentStoreCoordinator;
}

@property ( nonatomic, strong ) NSPersistentStoreCoordinator * persistentStoreCoordinator;

@end