import java.lang.reflect.*;

// 业务接口
interface UserService {
    String getUser(int id);
}

// 真实业务类
class UserServiceImpl implements UserService {
    public String getUser(int id) {
        return "User-" + id;
    }
}

// 动态代理处理器
class LoggingProxyHandler implements InvocationHandler {
    private Object target;

    public LoggingProxyHandler(Object target) {
        this.target = target;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("Before method: " + method.getName());
        Object result = method.invoke(target, args);
        System.out.println("After method: " + method.getName());
        return result;
    }
}

// 客户端使用
public class AdvancedDynamicProxy {
    public static void main(String[] args) {
        UserService realService = new UserServiceImpl();
        
        UserService proxyInstance = (UserService) Proxy.newProxyInstance(
            UserService.class.getClassLoader(),
            new Class[]{UserService.class},
            new LoggingProxyHandler(realService)
        );
        
        System.out.println(proxyInstance.getUser(101));
    }
}