java - GUICE：根据范围注入值

Question

我有一个控制器类。

此类需要不同的枚举值，具体取决于注入的位置。我不想为控制器创建子类。

我怎样才能做到这一点？

例子：

class FirstItem {

    //some of these have an injected controller which needs the enum value 'FIRST'
    @Inject
    @FirstSubItems //Custom annotation for multibinding
    Set<Item> subItems;
}

class SecondItem {

    //some of these have an injected controller which needs the enum value 'SECOND'
    @Inject
    @SecondSubItems //Custom annotation for multibinding
    Set<Item> subItems;
}

class Controller {
    @Inject
    MyEnum enumValue;
}

这可以优雅地完成吗？我将如何配置模块？

该模块目前看起来像这样：

Multibinder<Item> toolsSectionOne = Multibinder.newSetBinder(binder, Item.class, FirstSubItems.class);
toolsSectionOne.addBinding().to(Item1.class);
toolsSectionOne.addBinding().to(Item2.class);

Multibinder<Item> toolsSectionTwo = Multibinder.newSetBinder(binder, Item.class, SecondSubItems.class);
toolsSectionTwo.addBinding().to(Item1.class);
toolsSectionTwo.addBinding().to(Item2.class);

Answer 1

我用 PrivateBinder 解决了我的问题：

Type type = TypeLiteral.get(Item.class).getType();
Type setType = Types.setOf(type);

PrivateBinder privateBinderOne = binder.newPrivateBinder();
privateBinderOne.bind(MyEnum.class).toInstance(MyEnum.FIRST);
Multibinder<Item> toolsSectionOne = Multibinder.newSetBinder(privateBinderOne , Item.class, FirstSubItems.class);
toolsSectionOne.addBinding().to(Item1.class);
toolsSectionOne.addBinding().to(Item2.class);
privateBinderOne.expose(Key.get(setType, FirstSubItems.class));

PrivateBinder privateBinderTwo = binder.newPrivateBinder();
privateBinderTwo.bind(MyEnum.class).toInstance(MyEnum.SECOND);
Multibinder<Item> toolsSectionTwo = Multibinder.newSetBinder(privateBinderTwo , Item.class, SecondSubItems.class);
toolsSectionTwo.addBinding().to(Item1.class);
toolsSectionTwo.addBinding().to(Item2.class);
privateBinderTwo.expose(Key.get(setType, SecondSubItems.class));

这就像一个魅力。