java - 具有列表值的 Guice MapBinder

Question

我有一项服务需要注入(inject) mulitmap - Map<String, List<Enricher>>

public class EnrichService {
    private Map<String, List<Enricher>> typeEnrichers;

    @Inject
    public EnrichService(Map<String, List<Enricher>> typeEnrichers) {
        this.typeEnrichers = typeEnrichers;
    }

    public void enrich(Entity entity) {
        List<Enricher> enrichers = typeEnrichers.get(entity.type);
        //.. enriching entity with enrichers
    }
}

class Entity {
    String id;
    String type = "shapedColorful";
    String color;
    String shape;
}

interface Enricher {
    void enrich(Entity entity);
}

class ColorEnricher implements Enricher {
    @Inject
    private  ColorService colorService;
    public void enrich(Entity entity) {
        entity.color = colorService.getColor(entity.id);
    }
}

class ShapeEnricher implements Enricher {
    @Inject
    private ShapeService shapeService;
    public void enrich(Entity entity) {            
        entity.shape = shapeService.getShape(entity.id);
    }
}

我需要有关在 juice 中配置 typeEnrichers Binder 的帮助这是我正在尝试的，但卡住了

bind(ColorService).to(ColorServiceImpl.class);
bind(ShapeService).to(ShapeServiceImpl.class);
MapBinder<RelationType, List<Enricher>> mapBinder = MapBinder.newMapBinder(
            binder(), 
            new TypeLiteral<String>() {},
            new TypeLiteral<List<Enricher>>() {});

mapBinder.addBinding("shapedColorful", to(/*how to bind list of Enrichers here??*/))

任何帮助，我如何绑定(bind)这样的多图？

Answer 1

您正在尝试将 MapBinder 与 Multibinder 混合在一起。

我建议您为每个 MapBinder 关系创建一个 Provider。实际上 Multibinder 本身就是一个 List Provider，具体来说，它的 RealMultibinder 实现不幸的是包私有(private)并且禁止使用。如果它不是包私有(private)的，也许我们可以这样使用它。很可能它无论如何都行不通......恕我直言，这会很好。

bind(ColorService).to(ColorServiceImpl.class);
bind(ShapeService).to(ShapeServiceImpl.class);
MapBinder<RelationType, List<Enricher>> mapBinder = MapBinder.newMapBinder(
            binder(), 
            new TypeLiteral<String>() {},
            new TypeLiteral<List<Enricher>>() {});

mapBinder.addBinding("shapedColorful", toProvider(Multibinder.newSetBinder(this.binder(), Enricher.class).addBinding().to(ColorService.class).addBinding().to(ShapeService.class).asEagerSingleton()))

您仍然可以创建并使用提供程序:

public class ShapeColorfulProvider implements Provider<List<Enricher>> {
 @Inject private ColorService colorService;
 @Inject private ShapeService shapeService;

 public List<Enricher> get() {
   return Lists.newArrayList(colorService,shapeService);
 }

}

然后

   mapBinder.addBinding("shapedColorful", toProvider(ShapeColorfulProvider.class))