问题描述
我是否需要创建一个新模块,其中接口绑定到不同的实现?
Do I need to create a new module with the Interface bound to a different implementation?
Chef newChef = Guice.createInjector(Stage.DEVELOPMENT, new Module() {
@Override
public void configure(Binder binder) {
binder.bind(FortuneService.class).to(FortuneServiceImpl.class);
}
}).getInstance(Chef.class);
Chef newChef2 = Guice.createInjector(Stage.DEVELOPMENT, new Module() {
@Override
public void configure(Binder binder) {
binder.bind(FortuneService.class).to(FortuneServiceImpl2.class);
}
}).getInstance(Chef.class);
我无法触及Chef Class和Interfaces。我只是一个客户端在运行时绑定到Chef的FortuneService到不同的接口。
I cannot touch the Chef Class nor the Interfaces. I am just a client binding to Chef's FortuneService to different Interfaces at runtime.
推荐答案
看起来像部分。 如何创建一个带有两个Leg对象的机器人,左边的一个用LeftFoot注入,另一个用RightFoot注入。但只有一个Leg类在两个上下文中都被重用。
Take looks like the Robot Legs section, described in the Guice FAQ. "How to create a robot with a two Leg objects, the left one injected with a LeftFoot, and the right one with a RightFoot." But only one Leg class that's reused in both contexts.
有一个PrivateModules解决方案。它使用两个独立的私有模块,一个是@Left,另一个是@Right。每个都有未注释的Foot.class和Leg.class的绑定,并为带注释的Leg.class公开绑定:
There's a PrivateModules solution. It uses two separate private modules, a @Left one and an @Right one. Each has a binding for the unannotated Foot.class and Leg.class, and exposes a binding for the annotated Leg.class:
class LegModule extends PrivateModule {
private final Class<? extends Annotation> annotation;
LegModule(Class<? extends Annotation> annotation) {
this.annotation = annotation;
}
@Override protected void configure() {
bind(Leg.class).annotatedWith(annotation).to(Leg.class);
expose(Leg.class).annotatedWith(annotation);
bindFoot();
}
abstract void bindFoot();
}
...并将它们粘合在一起:
...and to glue it all together:
public static void main(String[] args) {
Injector injector = Guice.createInjector(
new LegModule(Left.class) {
@Override void bindFoot() {
bind(Foot.class).toInstance(new Foot("leftie"));
}
},
new LegModule(Right.class) {
@Override void bindFoot() {
bind(Foot.class).toInstance(new Foot("righty"));
}
});
}
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