我希望你能帮忙将我的系统从Java迁移到Scala。在我的Java代码中,我使用了注册表模式来从字符串中获取实现。在Scala中有类似的东西吗?我是Scala新手,有人能给我指出正确的参考资料吗?
我的Java代码:
public class ItemRegistry {
private final Map<String, ItemFactory> factoryRegistry;
public ItemRegistry() {
this.factoryRegistry = new HashMap<>();
}
public ItemRegistry(List<ItemFactory> factories) {
factoryRegistry = new HashMap<>();
for (ItemFactory factory : factories) {
registerFactory(factory);
}
}
public void registerFactory(ItemFactory factory) {
Set<String> aliases = factory.getRegisteredItems();
for (String alias : aliases) {
factoryRegistry.put(alias, factory);
}
}
public Item newInstance(String itemName) throws ItemException {
ItemFactory factory = factoryRegistry.get(itemName);
if (factory == null) {
throw new ItemException("Unable to find factory containing alias " + itemName);
}
return factory.getItem(itemName);
}
public Set<String> getRegisteredAliases() {
return factoryRegistry.keySet();
}
}
我的物品接口:
public interface Item {
void apply(Order Order) throws ItemException;
String getItemName();
}
我把字符串映射为以下内容:
public interface ItemFactory {
Item getItem(String itemName) throws ItemException;
Set<String> getRegisteredItems();
}
public abstract class AbstractItemFactory implements ItemFactory {
protected final Map<String, Supplier<Item>> factory = Maps.newHashMap();
@Override
public Item getItem(String alias) throws ItemException {
try {
final Supplier<Item> supplier = factory.get(alias);
return supplier.get();
} catch (Exception e) {
throw new ItemException("Unable to create instance of " + alias, e);
}
}
protected Supplier<Item> defaultSupplier(Class<? extends Item> itemClass) {
return () -> {
try {
return itemClass.newInstance();
} catch (InstantiationException | IllegalAccessException e) {
throw new RuntimeException("Unable to create instance of " + itemClass, e);
}
};
}
@Override
public Set<String> getRegisteredItems() {
return factory.keySet();
}
}
public class GenericItemFactory extends AbstractItemFactory {
public GenericItemFactory() {
factory.put("reducedPriceItem", () -> new Discount(reducedPriceItem));
factory.put("salePriceItem", () -> new Sale(reducedPriceItem));
}
}
Sale和Discount是Item的实现。我在ItemRegistry中使用newInstance方法根据名称获取类。有没有类似的东西可以让我在Scala中完成同样的操作?