프록시 - 프록시 적용

컨트롤러

@RequiredArgsConstructor
public class OrderControllerInterfaceProxy implements OrderControllerV1 {
    private final OrderControllerV1 target;
    private final LogTrace logTrace;
    @Override
    public String request(String itemId) {
        TraceStatus status = null;
        try {
            status = logTrace.begin("OrderController.request()");
            //target 호출
            String result = target.request(itemId);
            logTrace.end(status);
            return result;
        } catch (Exception e) {
            logTrace.exception(status, e);
            throw e;
        }
    }

    @Override
    public String noLog() {
        return target.noLog();
    }
}

서비스

@RequiredArgsConstructor
public class OrderServiceInterfaceProxy implements OrderServiceV1 {
    private final OrderServiceV1 target;
    private final LogTrace logTrace;
    @Override
    public void orderItem(String itemId) {
        TraceStatus status = null;
        try {
            status = logTrace.begin("OrderService.orderItem()");
            //target 호출
            target.orderItem(itemId);
            logTrace.end(status);
        } catch (Exception e) {
            logTrace.exception(status, e);
            throw e;
        }
    }
}

리포지토리

@RequiredArgsConstructor
public class OrderRepositoryInterfaceProxy implements OrderRepositoryV1 {

    private final OrderRepositoryV1 target;
    private final LogTrace logTrace;

    @Override
    public void save(String itemId) {
        TraceStatus status = null;

        try {
            status = logTrace.begin("OrderRepository.save()");
            //target 호출
            target.save(itemId);
            logTrace.end(status);
        } catch (Exception e) {
            logTrace.exception(status, e);
            throw e;
        }
    }
}

설정

@Configuration
public class InterfaceProxyConfig {
    @Bean
    public OrderControllerV1 orderController(LogTrace logTrace) {
        OrderControllerV1Impl controllerImpl = new OrderControllerV1Impl(orderService(logTrace));
        return new OrderControllerInterfaceProxy(controllerImpl, logTrace);
    }

    @Bean
    public OrderServiceV1 orderService(LogTrace logTrace) {
        OrderServiceV1Impl serviceImpl = new OrderServiceV1Impl(orderRepository(logTrace));
        return new OrderServiceInterfaceProxy(serviceImpl, logTrace);
    }

    @Bean
    public OrderRepositoryV1 orderRepository(LogTrace logTrace) {
        OrderRepositoryV1Impl repositoryImpl = new OrderRepositoryV1Impl();
        return new OrderRepositoryInterfaceProxy(repositoryImpl, logTrace);
    }
}

메인

@Import(InterfaceProxyConfig.class)
@SpringBootApplication(scanBasePackages = "hello.proxy.app.v1")
public class ProxyApplication {

	public static void main(String[] args) {
		SpringApplication.run(ProxyApplication.class, args);
	}

	@Bean
	public LogTrace logTrace() {
		return new ThreadLocalLogTrace();
	}

}

핵심

• 실제 구현 클래스의 객체가 아니라 프록시 객체를 빈으로 등록하여 사용함
• 실제 구현 클래스의 객체는 빈에는 등록되지 않지만 프록시 빈 등록 시 힙메모리에 올라가서 실제 만들어진다
• 구현 클래스의 객체는 프록시 객체에서 target으로 사용함