如何用 Guice 注入 Hk2 bean

Question

There is a dropwizard app, which is jersey based. I rewrote Hk2 bean definitions into Guice and now I can inject Guice beans into Jersey Resources, but I noticed that Hk2 beans, defined in dropwizard bundles, which I cannot rewrite, are not visible by Guice and it fails to inject dependencies defined in Hk2.
Guice doesn't see beans defined in Hk2 bundles and Guice creates new uninitialized beans by default. I disabled this behavior with requireExplicitBindings.

I experimented with HK2IntoGuiceBridge, but its matcher is not invoked for beans I am interested in. ConfiguredBundleX is located in external artifact.

I tried to copy and translate bean definitions from bundles and stuck with jersey bean Provider<ContainerRequest> , I have no idea where it comes from.

public class ConfiguredBundleX implements ConfiguredBundle<MyAppConf> {
  public void run(T configuration, Environment environment) throws Exception {
    environment.jersey().register(new AbstractBinder() {
            protected void configure() {
                this.bind(new MyHk2Bean()).to(MyHk2Bean.class);
            }
        });
  }  
}

public class DependsOnHk2Bean { @Inject public DependsOnHk2Bean(MyHk2Bean b) {} }

public class MainModule extends AbstractModule {
    private final ServiceLocator locator;
    protected void configure() {
      binder().requireExplicitBindings();

      install(new HK2IntoGuiceBridge(locator));
      bind(DependsOnHk2Bean.class);
}

public class GuiceFeature implements Feature {
    public boolean configure(FeatureContext context) {
        ServiceLocator locator = ServiceLocatorProvider.getServiceLocator(context);
        GuiceBridge.getGuiceBridge().initializeGuiceBridge(locator);
        Injector injector = Guice.createInjector(
                new HK2IntoGuiceBridge(locator),
                new MainModule(locator));

        GuiceIntoHK2Bridge guiceBridge = locator.getService(GuiceIntoHK2Bridge.class);
        guiceBridge.bridgeGuiceInjector(injector);
        return true;
    }
}
// ...

 public void initialize(Bootstrap<X> bootstrap) {
   bootstrap.addBundle(new ConfiguredBundleX());
 }

 public void run(X config, Environment env) {
   env.jersey().register(new GuiceFeature());
 }

Answer 1

Unfortunately in Guice beans you have to use @HK2Inject rather than @Inject in order to inject hk2 beans into Guice. So in your code above you would do:

public class DependsOnHk2Bean { @HK2Inject public DependsOnHk2Bean(MyHk2Bean b) {} }

This is because of limitation in guice (it may be fixed by now) such that @Inject behavior could not overwritten

I have not tried the above code myself so I'm not sure it'll work, but that was the deal back when the bridge was written...

See HK2Inject and injecting-hk2-services-into-guice-services

Answer 2

After digging Guice and HK2ToGuiceTypeListenerImpl I figured out that there is bindListener to kind of intercept missing bindings and pull them from somewhere. @HKInject code is there, but I noticed that the listener is not called for some bean including the bean I was interested in. Yes HKInject doesn't support constructor injection (4.2.1 version)

So I decided to manually import HK beans and bind them in Guice. Dropwizard terminology is horrible there are methods get context something, get admin context is totally something different and beans must be get with getService method!

@RequiredArgsConstructor
public class HkModule extends AbstractModule {
    private final ServiceLocator locator;

    @Override
    protected void configure() {
        binder().requireExplicitBindings();

        Provider<Bar> barProvider = locator.getService(
                new TypeLiteral<Provider<Bar>>(){}.getType());
        bind(Bar.class).toProvider(barProvider);
        bind(Foo.class).toInstance(locator.getService(Foo.class));
    }
}