How to maintain proper encapsulation for singleton created with data - ios

Question

I have a singleton networking class as well as a singleton object that needs to persist throughout my app. The singleton is initialized based on data retrieved from a web call, so right now my code works, and I have the following in my singleton networking class:
- (void)initializeObjectWithSuccess:(void (^)(BOOL))success
failure:(void (^)(NSError *error))failure {
[self.HTTPClient postPath:[NSString stringWithFormat:#"users/%#/", [CPUser sharedUser].name parameters:[self createParameters] success:^(AFHTTPRequestOperation *operation, id responseObject) {
id json = [NSJSONSerialization JSONObjectWithData:responseObject
options:NSJSONReadingAllowFragments
error:nil];
[[CPList sharedList] setIdentifier:json[#"id"]];
[[CPList sharedList] setImages:json[#"images"]];
if (success) {
success(YES);
}
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
failure(error);
}];
}
I don't know how to initialize all the properties I need on my singleton CPList without setting them within this method, however I know that this is not proper encapsulation because the CPRequestManager Class should know nothing about the CPList Class

Answer 1

If your issue is that you don't want this class to know the name of CPList and the detail that it's a singleton and that it can access it with +[CPList sharedInstance] then you can just pass in an object that conforms to a protocol. This basically moves the knowledge of the singleton somewhere else
- (void)initializeObjectWithList:(id<CPList>)list
success:(void (^)(BOOL))success
failure:(void (^)(NSError *error))failure;
{
[self.HTTPClient postPath:[NSString stringWithFormat:#"users/%#/", [CPUser sharedUser].name parameters:[self createParameters] success:^(AFHTTPRequestOperation *operation, id responseObject) {
id json = [NSJSONSerialization JSONObjectWithData:responseObject
options:NSJSONReadingAllowFragments
error:nil];
[list setIdentifier:json[#"id"]];
[list setImages:json[#"images"]];
if (success) {
success(YES);
}
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
failure(error);
}];
}
Or you could remove all knowledge that there is a "list" and just have this method return the actual data and then the caller can set it on the list
- (void)initializeObjectWithSuccess:(void (^)(NSString *ID, NSArray *images))success
failure:(void (^)(NSError *error))failure;
{
[self.HTTPClient postPath:[NSString stringWithFormat:#"users/%#/", [CPUser sharedUser].name parameters:[self createParameters] success:^(AFHTTPRequestOperation *operation, id responseObject) {
id json = [NSJSONSerialization JSONObjectWithData:responseObject
options:NSJSONReadingAllowFragments
error:nil];
if (success) {
success(json[#"id"], json[#"images"]);
}
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
failure(error);
}];
}
Without any further context it's hard to suggest structural changes but here's two potential refactoring that might get you thinking about what you coudld do