Service : Service shouldn't have multiple repositories dependencies

Medium

---

DDD

What is it?

This practice is activated when a service class depends on multiple repository interfaces, indicating a potential violation of the single responsibility principle and increased coupling within the service layer.

Why apply it?

Reducing a service's dependencies to a single repository or a cohesive group of repositories is crucial to maintain code clarity, facilitate easier testing, and enhance maintainability by ensuring the service remains focused on a specific domain or responsibility.

How to fix it?

Refactor the service to consolidate repository interactions, possibly by using a single or aggregated repository, or by delegating some interactions to another service or a dedicated class that encapsulates multi-repository operations.

Read more:

https://martinfowler.com/bliki/AnemicDomainModel.html

Examples

Example 1:

Negative

Incorrect implementation that violates the practice.

using Microsoft.Data.SqlClient;

namespace Practices.DDD.Service.SQLTransaction
{
    public class OrderStatusService
    {
        private readonly OrderRepository _orderRepository;
        private readonly OrderStatusRepository _orderStatusRepository;

        public OrderStatusService(OrderRepository orderRepository, OrderStatusRepository orderStatusRepository)
        {
            _orderRepository = orderRepository;
            _orderStatusRepository = orderStatusRepository;
        }

        public void UpdateData(Order order, int status)
        {
            //Process Order
            _orderRepository.UpdateData(order);
            //Process Status
            _orderStatusRepository.UpdateStatus(order, status);
        }

    }
}