Design Pattern

Design Pattern

// SINGLETON PATTERN
-->.h:
  + (instancetype)sharedInstance;
-->.m:
  + (instancetype)sharedInstance
{
    static MyClass *sharedInstance = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sharedInstance = [[MyClass alloc] init];
        // Do any other initialisation stuff here
    });
    return sharedInstance;
}