Tracking object changes with an accessor

#import <Foundation/Foundation.h>
#import <EOControl/EOControl.h>
 
 
@interface PermanentGlobalID : EOTemporaryGlobalID
@end
 
@implementation PermanentGlobalID : EOTemporaryGlobalID
 
- (BOOL) isTemporary
{
   return( NO);
}
 
@end
 
 
@interface MutableDictionary : NSMutableDictionary
{
   NSMutableDictionary   *dictionary_;
}
 
@end
 
 
@implementation MutableDictionary : NSMutableDictionary
 
- (id) init
{
   dictionary_ = [NSMutableDictionary new];
   return( self);
}
 
- (void) dealloc
{
   [dictionary_ release];
   [super dealloc];
}
 
 
- (void) setObject:(id) obj
            forKey:(id) key
{
   [self willChange];
   [dictionary_ setObject:obj
                   forKey:key];
}
 
@end
 
 
int main (int argc, const char * argv[])
{
   NSAutoreleasePool   *pool;
   EOEditingContext    *context;
   MutableDictionary   *obj;
   MutableDictionary   *obj2;
   EOGlobalID          *gid;
 
   pool = [NSAutoreleasePool new];
 
   context = [[EOEditingContext new] autorelease];
 
   obj = [[MutableDictionary new] autorelease];
   gid = [[PermanentGlobalID new] autorelease];
   [context recordObject:obj
                globalID:gid];
 
   NSLog( @"A) %d updatedObjects, %d registeredObjects",
         [[context updatedObjects] count], [[context registeredObjects] count]);
 
   [obj setObject:@"VfL Bochum 1848"
           forKey:@"name"];
 
   NSLog( @"B) %d updatedObjects, %d registeredObjects",
         [[context updatedObjects] count], [[context registeredObjects] count]);
 
   obj2 = [[MutableDictionary new] autorelease];
   [context insertObject:obj2];
 
   NSLog( @"C) %d updatedObjects, %d registeredObjects",
         [[context updatedObjects] count], [[context registeredObjects] count]);
 
   [obj2 setObject:@"VfL Bochum 1848"
            forKey:@"name"];
 
   NSLog( @"D) %d updatedObjects, %d registeredObjects",
         [[context updatedObjects] count], [[context registeredObjects] count]);
 
   [pool release];
   return( 0);
}

// forward functionality to NSMutableDictionary
- (NSMethodSignature *) methodSignatureForSelector:(SEL) sel
{
   return( [dictionary_ methodSignatureForSelector:sel]);
}
 
 
- (void) forwardInvocation:(NSInvocation *) invocation
{
   SEL  sel;
 
   sel = [invocation selector];
   if (! [dictionary_ respondsToSelector:sel])
   {
      // does this ever happen ? 
      [self doesNotRecognizeSelector:sel];
      return;
   }
 
   [invocation invokeWithTarget:dictionary_];
}