普通版单例
class TheOneAndOnlyKraken {
static let sharedInstance = TheOneAndOnlyKraken()
//This prevents others from using the default '()' initializer for this class.
private init() {}
}
多线程版单例
class func theOneAndOnlyKraken() -> TheOneAndOnlyKraken{
struct Singleton {
static var predicate:dispatch_once_t = 0
static var instance:TheOneAndOnlyKraken? = nil
}
dispatch_once(&Singleton.predicate, {
Singleton.instance = TheOneAndOnlyKraken()
})
return Singleton.instance!
}
