Appendix B. SmartyPants for Adobe Flex

 

Contributed by Josh McDonald

SmartyPants-IOC is a dependency injection framework for use in building Adobe Flex and Flash applications inspired by Google Guice for Java. It’s based on key concepts:

  • The class+name key
  • Injector requests, usually specified via metadata
  • Injector rules, specified using an ActionScript-based DSL

B.1. The class+name key

Whether you’re telling SmartyPants-IOC what to provide or sitting around with your hand out asking for a dependency, the key is the same: a combination of a class and a name. You must specify the class, but the name is optional.

B.1.1. Injection annotations

How do you actually request that a field be injected? In most circumstances you need to annotate your fields with ActionScript metadata. If you want to request an instance of IServiceInterface, the syntax is simple: 

[Inject]
public var myService:IServiceInterface;

Let’s say you want to look up a particular string, rather than just anything. For a Web Services Description Language (WSDL) URL, or something along those lines, use this syntax: 

[Inject(name="mainWSDL")]
public var myServiceWSDL:String;

These fields will be injected into your object when it’s constructed for you by SmartyPants-IOC or when you call injector.injectInto(myInstance).

SmartyPants-IOC also supports live injections, which when coupled with live rules behave like the Flex SDK’s data-binding functionality:

B.2. Injector rules