Tada

registries.java

interface Registries extends Registry<String, Registry> {
  
  void addChild(Registries child);
  
}

interface Registry<K, V> {
  
  Set<V> getValues();
  
  Optional<V> get(K key);
  
}



interface HorseTypeRegistry extends Registry<String, HorseType> {
  
}

class GameRegistries extends Registries {
  
  GameRegistries() {
    
  }
  
}

class EntityRegistries extends Registries {
  
  EntityRegistries() {
    addChild(new GameRegistries);
    add(new HorseTypeRegistry);
  }
  
}