Single-case mode a hungry man ARC

With the first two articles here directly to the code, this method is not purely a hungry man style, compared to lazy code will be a little bit easier, but the official Apple does not recommend, to understand the good.

There is no multithreading at this time, creating a singleton object before using it, there is no thread at this time. So no lock is required.

Static id _instance = NIL;

+ (void) load{//load is automatically called after the class is loaded.

_instance = [[Self alloc] init];

}

Alloc new will come here, so it's more appropriate to rewrite it here.

+ (ID) allocwithzone: (struct _nszone *) zone

{

if (_instance = = nil) {//Prevent creation of multiple

_instance = [Super Allocwithzone:zone];

}

return _instance;

}

-(ID) Copywithzone: (Nszone *) zone

{

return _instance;

}

+ (Instancetype) Sharedmusictool

{

return _instance;

}

Single-case mode a hungry man ARC