New Auto-wiring API

[alexgarbarev]

Today I intoroduced new API for auto-wiring. (I want to remove old one)
It's called auto-injection (to avoid name collision with original auto-wiring)
The auto-injection API looks:

@interface AutoInjectionKnight : Knight

@property(nonatomic, strong) InjectedProtocol(Quest) autoQuest;
@property(nonatomic, strong) InjectedClass(Fort) autoFort;

@end

That's all. Typhoon will automatically inject autoQuest property by definition for protocol Quest, and inject autoFort property by definition for class Fort.

Further discussions

• Remove old auto-wiring and do code cleanup?
• intoroduce more flexible injection-by-type mechanism. For example it can be excluding concrete definitions from "injection-by-type" lookup (maybe just one extra property for TyphoonDefinition).

Why we need more flexible injection-by-type?
Let's look to the real example: we have webService protocol and two implementation - real and stub.
Assembly can be looks like:

- (id<WebService>)stubWebService
{
    return [TyphoonDefinition withClass:[StubWebService class]];
}
- (id<WebService>)httpWebService
{
    return [TyphoonDefinition withClass:[HttpWebService class]];
}
- (id<WebService>)webService
{
    return [TyphoonDefinition withOption:TyphoonConfig(@"webservice.offline") yes:[self stubWebService] no:[self httpWebService]];
}

So there is three definitions of same protocol. Injection-by-type will fail with exception for WebService protocol. To handle this situation appropriately, we may need to remove stubWebService and httpWebService from the lookup. Then injection-by type will find only webService definition that return right definition based on config value.

There is another work to do: [TyphoonDefinition withOption... and [TyphoonDefinition withFactory... definitions should have correct type if possible. Currently they hold [NSObject class] type as stub but this is problem when using "injection-by-type".

[jasperblues]

Great work. This is much better than the old auto-wiring. I think its fairly safe to remove the old feature immediately.

I'm not sure if its appropriate or possible for us, but DI frameworks in other languages include a qualifier attribute for cases where by type injection is not possible:

//Disambiguate and force Typhoon to inject the stub web service
@property(nonatomic, strong) InjectedProtocol(@selector(stubWebService), WebService) webService

I can see my self using this for view controllers. Another place where I would particularly like to use it is in Integration tests - so instead of setting up a factory, and pulling components for integrations tests, we could just:

• Declare the assemblies (perhaps reference a reusable list, as most tests will use the same. therefore if that list changes, only need to update one place)
• Declare a property to participate in the integration test using the above style.

[jasperblues]

I'll update the docs over the weekend.

[jasperblues]

Fixes #189 ?

[alexgarbarev]

#189 - yes, it's fixed.

[fatuhoku]

The old documentation for Autowiring is still over at https://github.com/typhoon-framework/Typhoon/wiki/Autowiring and needs removing. It confused me for a good while!

[jasperblues]

@fatuhoku sorry about that. Will update today.