Sample Applications/CoreRecipesApp/MainApplication/Sources/Application/GroupViewTreeController.m

/*
 
 File: GroupViewTreeController.m
 
 Abstract: NSObjectController subclasses used for displaying information in 
 the outline and table views of the main window of the application.  
 
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 */
 
 
#import "GroupViewTreeController.h"
#import "InferenceCore.h"
 
@implementation GroupViewTreeController
 
/**
    Overridden from NSObjectController so that root level objects are only from 
    the main store and the default Library (in memory store).  Without this 
    change the objects listed would be from different stores, which can cause
    problems when you attempt to relate objects.
*/
 
- (BOOL)fetchWithRequest:(NSFetchRequest *)fetchRequest merge:(BOOL)merge error:(NSError **)error {
 
    // variables
    NSMutableArray *stores = [NSMutableArray array];
    InferenceCore *inferenceCore = [InferenceCore defaultCore];
    
    // get the primary store from the inference core
    id store = [inferenceCore inferredValueForKeyPath:@"primaryStore"];
    if (store != nil) {
        [stores addObject:store];
    }
    
    // get the in-memory store from the inference core
    store = [inferenceCore inferredValueForKeyPath:@"inMemoryStore"];
    if (store != nil) {
        [stores addObject:store];
    }
    
    // set the affected stores
    [fetchRequest setAffectedStores:stores];
    return [super fetchWithRequest:fetchRequest merge:merge error:error];
}
 
@end
 
@implementation MainStoreArrayController
 
/**
    Mutator to set the affected stores for the controller.  This allows the
    controller to customize which stores are used when fetching (to avoid
    accidental cross-store relationships.
*/
 
- (void)setAffectedStores:(NSArray *)newStores {
 
    if (affectedStores != newStores) {
        [affectedStores release];
        affectedStores = [newStores copy];   
    }
}
 
 
/**
    Overridden from NSObjectController so that root level objects are only from 
    the main store and the default Library (in memory store).  Without this 
    change the objects listed would be from different stores, which can cause
    problems when you attempt to relate objects.
*/
 
- (BOOL)fetchWithRequest:(NSFetchRequest *)fetchRequest merge:(BOOL)merge error:(NSError **)error {
 
    // get the local information
    NSMutableArray *stores = affectedStores;
    if (affectedStores == nil) {
        
        // get the information from the inference core
        stores = [NSMutableArray array];
        InferenceCore *inferenceCore = [InferenceCore defaultCore];
        
        // get the primary store 
        id store = [inferenceCore inferredValueForKeyPath:@"primaryStore"];
        if (store != nil) {
            [stores addObject:store];
        }
    }
 
    // set the affected stores
    [fetchRequest setAffectedStores:stores];
    return [super fetchWithRequest:fetchRequest merge:merge error:error];
}
 
@end