Question

I have a global dictionary with Class objects and NSString keys. Every custom subclass of my Property class can register itself on the Property superclass using

+ (void)registerPropertyClass:(Class)pclass forNamePrefix:(NSString *)namePrefix

A Property is initialized with a name and value. What I want to do now is return a different class from the init method based on the name prefix (if a registered class matches).

Would something like this be correct?

- (id)initWithName:(NSString *)name value:(NSString *)value
  id instance = self;

  NSArray *registeredPrefixes = [kCKPropertyClasses allKeys];
  for (NSString *prefix in registeredPrefixes) {
    if ([name rangeOfString:prefix].location == 0) {
      instance = [[kCKPropertyClasses objectForKey:prefix] alloc];
      break;
    }
  }

  self = [instance init];
  if (self) {
    self.name = name;
    self.value = value;
  }
  return self;
}

UPDATE: Forgot to mention that this project is using ARC (so no retain/release)

Answer 1

Without compiling it, that’ll work, but leak under manual-retain-release. You need to release self prior to the reassignment self = [instance init];.

With ARC, it should be fine.