dependency-injection

问题 I have an existing object hierarchy where some objects have fields that need to be injected. Also there are some other objects that are constructed using Google Guice and need to be injected with references to some objects from previously described object hierarchy. How do I do such kind of injection with Guice? The problem is that objects from existing hierarchy were not constructed using Guice, and therefore are not subject to inject process by default. There is, of course injector

问题 Imagine a staged application context with different phases. We start with an early phase to define the necessary infrastructure. The xml application contexts are loaded sequentially. The reason to split up these files is an extension/plugin mechanism. Stage 01-default-configuration.xml We prepare and declare the map with id exampleMapping to enhance them later with data. <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util

问题 Microsoft's Unity dependency injection framework can be configured either through code or through the applications configuration file (app.config). Code example: IUnityContainer container = new UnityContainer() .RegisterType<IInterface, ConcreteImplementation>(); Configuration example: <unity> <containers> <container> <types> <type type="IInterface, MyAssembly" mapTo="ConcreteImplementation, MyAssembly" /> What are the advantages/disadvantages to each approach? I can think of the obvious

问题 My configuration is: Wildfly 8.2.0, Weld Is it possible to inject in bean and not in its interface in CDI ? @Stateless class Bean implements IBean { ... } interface IBean { ... } @SessionScoped class Scoped { @Inject Bean bean; //Fail @Inject IBean iBean; //OK } EDIT : More Info in my previous question: Stateless EJB implements interface injection failed 回答1: Yes you can, but as EJB inject the business view the only business view you are exposing is the @Local view which is the default when

问题 There seems to be a lot of enthusiasm among Scala bloggers lately for the type classes pattern, in which a simple class has functionality added to it by an additional class conforming to some trait or pattern. As a vastly oversimplified example, the simple class: case class Wotsit (value: Int) can be adapted to the Foo trait: trait Foo[T] { def write (t: T): Unit } with the help of this type class: implicit object WotsitIsFoo extends Foo[Wotsit] { def write (wotsit: Wotsit) = println(wotsit

问题 So, I'm currently redesigning an Android app of mine to use Dagger. My app is large and complicated, and I recently came across the following scenario: Object A requires a special DebugLogger instance which is a perfect candidate for injection. Instead of passing around the logger I can just inject it through A's constructor. This looks something like this: class A { private DebugLogger logger; @Inject public A(DebugLogger logger) { this.logger = logger; } // Additional methods of A follow,

问题 Consider this scenario. I have some business logic that now and then will be required to write to a log. interface ILogger { void Log(string stuff); } interface IDependency { string GetInfo(); } class MyBusinessObject { private IDependency _dependency; public MyBusinessObject(IDependency dependency) { _dependency = dependency; } public string DoSomething(string input) { // Process input var info = _dependency.GetInfo(); var intermediateResult = PerformInterestingStuff(input, info); if

问题 I'm currently working on a ASP.NET Core Project and want to use the built-in Dependency Injection (DI) functionality. Well, I started with an interface: ICar { string Drive(); } and want to implement the ICar interface multiple times like public class BMW : ICar { public string Drive(){...}; } public class Jaguar : ICar { public string Drive(){...}; } and add the following in the Startup class public void ConfigureServices(IServiceCollection services) { // Add framework services. services

问题 I keep wanting to try this on a larger scale with our app + build system, but higher priorities keep pushing it to the back burner. It seems like a nice way to load Guice modules and avoids the common complaint about "hard coded configuration". Individual configuration properties rarely change on their own, but you will almost always have a set of profiles, usually for different environments (Debug, Production, etc). ServiceLoader lets you pull a list of all implementations defined as a

问题 I recently saw the talks Dead-Simple Dependency Injection and Dependency Injection Without the Gymnastics about DI with Monads and was impressed. I tried to apply it on a simple problem, but failed as soon as it got non-trivial. I really would like to see a running version of dependency injection where a class that depends on more than one value that has to be injected a class that depends on a class that depends on something to be injected as in the following example trait FlyBehaviour { def