使用 Micronaut 在 Java 中用于命令和处理程序的通用 class 注册表

Question

尝试在 Micronaut

中进行 java 泛型 class 的依赖注入

界面

public interface IRequestHandler<C, R> {
    R handler(C c);
}

依赖注入

@Singleton
public record ServiceBus(IRequestHandler<C, R> iRequestHandler) implements IServiceBus{

    @Override
    public <C, R> R send(C c) {
        return iRequestHandler.handler(c);
    }
}

界面

public interface IServiceBus {
    <C,R> R send(C c);
}

实施

public class ProductController {
    public ProductController(IServiceBus iRequestHandler){
        _iserviceBus= iRequestHandler;
    }
     public Mono<?> get(ProductSearchCriteriaCommand searchCriteria) {
            var item = _iserviceBus.<CreateProductCommand,CreateProductCommand>send(new CreateProductCommand());
            return null;
        }
}

我的问题出在 ServiceBus class 上，我如何传递 public record ServiceBus(IRequestHandler<C, R> iRequestHandler) 和 iRequestHandler.handler(c);

的类型

@Singleton
public class CreateProductCommandHandler implements IRequestHandler<CreateProductCommand, CreateProductCommand> {
    @Override
    public CreateProductCommand handler(CreateProductCommand createProductCommand) {
        return null;
    }
}

@Singleton
public record DeleteProductCommandHandler() implements IRequestHandler<DeleteProductCommand,DeleteProductCommand> {

    @Override
    public DeleteProductCommand handler(DeleteProductCommand deleteProductCommand) {
        return null;
    }
}

当我在控制器中调用 _iserviceBus.<CreateProductCommand,CreateProductCommand>send(new CreateProductCommand()); 时，我试图在 CreateProductCommandHandler class

中调用 handler 方法

类似地，如果我调用 _iserviceBus.<CreateProductCommand,CreateProductCommand>send(new DeleteProductCommand()); DeleteProductCommandHandler class 的 handler 方法应该调用

Answer 1

您错误地定义了 IServiceBus 接口：

public interface IServiceBus {
    <C,R> R send(C c);
}

应该是：

public interface IServiceBus<C,R> {
    R send(C c);
}

更新。非常基本的注册表示例。

public interface IRequestHandler<C, R> {

    R handler(C c);

    Class<C> getCmdType();
    
}

public class ServiceBus implements IServiceBus {

    private final Map<Class<?>, IRequestHandler<?, ?>> handlerMap;

    public ServiceBus(List<IRequestHandler<?, ?>> handlers) {
        handlerMap = handlers.stream()
                .collect(toMap(
                        IRequestHandler::getCmdType,
                        Function.identity()
                ));
    }

    @Override
    public <C, R> R send(C c) {
        IRequestHandler<C, R> handler = (IRequestHandler<C, R>) handlerMap.get(c.getClass());
        if (handler == null) {
            throw new UnsupportedOperationException("Unsupported command: " + c.getClass());
        }
        return handler.handler(c);
    }

}

使用 Micronaut 在 Java 中用于命令和处理程序的通用 class 注册表

Generic class registry for command and handler in Java with Micronaut

java

generics

java-8

java-11

micronaut