Transactions in the Repository Pattern

Question

How do I encapsulate the saving of more than one entity in a transactional manner using the repository pattern? For example, what if I wanted to add an order and update the

Answer 1

Using Spring.NET AOP + NHibernate you can write your repository class as normal and configure your transactions in custom XML file:

public class CustomerService : ICustomerService
{
    private readonly ICustomerRepository _customerRepository;
    private readonly IOrderRepository _orderRepository;

    public CustomerService(
        ICustomerRepository customerRepository, 
        IOrderRepository orderRepository) 
    {
        _customerRepository = customerRepository;
        _orderRepository = orderRepository;
    }

    public int CreateOrder(Order o, Customer c) 
    {
        // Do something with _customerRepository and _orderRepository
    }
}

In the XML file you select which methods you would like to be executed inside a transaction:

And in your code you obtain an instance of the CustomerService class like this:

ICustomerService customerService = (ICustomerService)ContextRegistry
    .GetContent()
    .GetObject("customerService");

Spring.NET will return you a proxy of the CustomerService class that will apply a transaction when you call CreateOrder method. This way there's no transaction specific code inside your service classes. AOP takes care of it. For more details you can take a look at the documentation of Spring.NET.