GCDでWaitForMultipleObjectsを代替する方法 ref: http://qiita.com/g-1/items/dde3f3c34c50c6d6f055

file0.txt

dispatch_group_t group = dispatch_group_create();

  [self.arrayLocalSearch removeAllObjects];

  NSError* error = nil;
  NSFetchRequest* fetchRequest = [[NSFetchRequest alloc] init];
  NSEntityDescription* entity = [NSEntityDescription entityForName:@"Location"
                                            inManagedObjectContext:[MapData sharedManager].managedObjectContext];

  [fetchRequest setEntity:entity];
  [fetchRequest setFetchBatchSize:40];
  NSArray* locations = [[MapData sharedManager].managedObjectContext executeFetchRequest:fetchRequest error:&error];
  if(error){
    LOG(@"Unresolved error %@ %@",error,[error userInfo]);
  }

  for(Location* location in locations){
    dispatch_group_enter(group);
    if (!location.geocoding) {
      [self searchShopLocation:location
                         block:^{
                           dispatch_group_leave(group);
                         }];
    }else{
      CustomMapItem* customItem = [[CustomMapItem alloc] init];
      customItem.location = location;
      self.mapAnnotations[location.name] = customItem;
      dispatch_group_leave(group);
    }
  }

  //全ての非同期処理が完了したら、メインスレッドで実行される
  dispatch_group_notify(group,
                        dispatch_get_main_queue(),
                        ^{
                          //NSLog(@"done");
                          [self.mapView removeAnnotations:self.mapView.annotations];  // remove any annotations that exist
                          NSMutableArray* array = [NSMutableArray arrayWithCapacity:self.mapAnnotations.count];
                          for (id key in [self.mapAnnotations keyEnumerator]) {
                            [array addObject:self.mapAnnotations[key]];
                          }

                          [self.mapView addAnnotations:array];
                        });