tsJensen

A quest for software excellence...

Software Architecture: Use Cases, Not Frameworks

I enjoy continually learning from Robert Martin (Uncle Bob). Sometimes I disagree with him but usually only until I’ve thoroughly processed what he is trying to teach me. In his latest missive on 8thlight.com, Uncle Bob writes a stunningly cogent brief called Screaming Architecture in which he makes a critical point: software architecture is all about the use cases of a system and NOT the framework.

“Architectures are not (or should not) be about frameworks. Architectures should not be supplied by frameworks. Frameworks are tools to be used, not architectures to be conformed to. If your architecture is based on frameworks, then it cannot be based on your use cases.”

Focus on the use cases and perhaps even group them into logical hierarchies with tidy “40,000 foot level” epochs that describe the thing you are building. Is it a customer relationship management system? The first thing we should notice in an architecture, whether document or code, is that this is a CRM system. Presentation, delivery, storage and communication frameworks are all secondary, just plumbing, not the architecture.

“A good software architecture allows decisions about frameworks, databases, web-servers, and other environmental issues and tools, to be deferred and delayed.”

I’m not completely at this point in my journey toward architectural perfection but I recognize the need to strive for this idea of producing architectures that are designed to solve the problems of the users first rather than designed fit within the strictures of a framework while addressing the use cases after the fact.

I recommend you read the full article. Take Uncle Bob’s advice, as I intend to do, and focus more strongly on architecture for your use cases on your next project. Use frameworks carefully and work to keep your business code independent of your frameworks and thus imminently more testable. And don’t forget your tests.