用Guice注入班级集合 [英] Injecting Collection of Classes with Guice

问题描述

我正在尝试使用Google Guice 2.0注入内容，并且具有以下结构:

I'm trying to inject things with Google Guice 2.0 and I have the following structure:

FooAction implements Action
BarAction implements Action

然后我有了一个带有以下构造函数的ActionLibrary:

I then have an ActionLibrary with the following constructor:

ActionLibrary (List<Action> theActions)

当我从Guice请求一个ActionLibrary实例时，我希望Guice识别两个已注册的Action类(FooAction，BarAction)并将它们传递给构造函数.这样做的动机是，当我添加第三个动作BazAction时，就像在Module中注册它一样简单，它会自动添加到构造函数中的列表中.

When I request an instance of ActionLibrary from Guice, I would like Guice to identify both of the registered Action classes (FooAction, BarAction) and pass them into the constructor. The motivation here being that when I add a third action BazAction, it would be as simple as registering it in the Module and it would automatically be added to the list in the constructor.

这可能吗?

推荐答案

您想要的是多绑定.具体来说，您想绑定Set<Action>(而不是List，但是无论如何Set可能都是您真正想要的)绑定，如下所示:

What you want for this is Multibindings. Specifically, you want to bind a Set<Action> (not a List, but a Set is probably what you really want anyway) like this:

Multibinder<Action> actionBinder = Multibinder.newSetBinder(binder(), Action.class);
actionBinder.addBinding().to(FooAction.class);
actionBinder.addBinding().to(BarAction.class);

然后您可以在任何地方@Inject Set<Action>.

Then you can @Inject the Set<Action> anywhere.

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