Design – Build – Run: Applied Practices and Principles for Production-Ready Software Development

14.4. The Business Processing Components

The business-processing components encapsulate all the business logic and functional components (including batch). The business-processing layer is used by the web services, batch processes, and possibly other external consumers (as required). This section takes a closer look at the components within the business-processing tier.

14.4.1. The Business Components

The web services call down to the core business-logic components that actually perform the required functionality. You've seen how the web pages relate to the web services and how the web services relate to the business managers. This section looks at the business managers and the business processes.

I prefer the methods in the business-logic layer to mirror actual functional scenarios and actions rather than a straight object-orientated design. I tend to design business components so that they mirror the user or functional journeys, rather than having a single component perform every task. For example, in this application, it would be possible to have a single Membership or Account component that encapsulated all the relevant functionality for creating new accounts, activating accounts, updating account details, and so forth. This would make for a fairly large component and, in most cases, restrict its development and testing to a single individual. In a very large system this functionality could simply form part of the overall solution. With respect to the case study, it is the ...