GWT-GIN多重实现？

Question

我有以下代码

public class AppGinModule extends AbstractGinModule{ 
    @Override 
    protected void configure() { 
     bind(ContactListView.class).to(ContactListViewImpl.class); 
     bind(ContactDetailView.class).to(ContactDetailViewImpl.class); 
    } 
} 

@GinModules(AppGinModule.class) 
public interface AppInjector extends Ginjector{ 
    ContactDetailView getContactDetailView(); 
    ContactListView getContactListView(); 
} 

在我的切入点

AppInjector appInjector = GWT.create(AppGinModule.class); 
appInjector.getContactDetailsView(); 

这里ContactDetailView总是与ContactsDetailViewImpl绑定。但我想在某些条件下与ContactDetailViewImplX绑定。

我该怎么做？请帮助我。

Answer 1

你不能通过声明告诉Gin在其他时间有时注入一个实现。不过，您可以使用Provider或@Provides method。

Provider例子：

public class MyProvider implements Provider<MyThing> { 
    private final UserInfo userInfo; 
    private final ThingFactory thingFactory; 

    @Inject 
    public MyProvider(UserInfo userInfo, ThingFactory thingFactory) { 
     this.userInfo = userInfo; 
     this.thingFactory = thingFactory; 
    } 

    public MyThing get() { 
     //Return a different implementation for different users 
     return thingFactory.getThingFor(userInfo); 
    } 
} 

public class MyModule extends AbstractGinModule { 
    @Override 
    protected void configure() { 
     //other bindings here... 

     bind(MyThing.class).toProvider(MyProvider.class); 
    } 
} 

@Provides例子：

public class MyModule extends AbstractGinModule { 
    @Override 
    protected void configure() { 
     //other bindings here... 
    } 

    @Provides 
    MyThing getMyThing(UserInfo userInfo, ThingFactory thingFactory) { 
     //Return a different implementation for different users 
     return thingFactory.getThingFor(userInfo); 
    } 
}