Software Architect's Handbook

Using dependency injection (DI)

One approach to handling cross-cutting concerns is to use the DI pattern, which we covered in Chapter 6, Software Development Principles and Practices. This pattern can be used to inject cross-cutting dependencies into classes that need them. This allows us to write loosely coupled code and avoid scattering. The logic for the cross-cutting concern will not be duplicated in multiple places.

For example, if we had an Order class that had logging and caching cross-cutting concerns, we could inject them like this:

public class Order{    private readonly ILogger _logger;    private readonly ICache _cache;    public Order(ILogger logger, ICache cache)    {        if (logger == null) throw new ArgumentNullException(nameof(logger)); ...