Handling of Non-Functional Requirements

Non-Functional Requirements (aka Quality Attributes) are the „bread and butter business" for software architects. Unfortunately, non-functional requirements are often abstract and hard to grasp. A good approach to tackle this are so-called “utility trees”. Utility trees list important non-functional requirements (say security, usability and performance) in a tree structure; beginning with “utility as root”. It’s a good approach to use the list for a first prioritization. Each level in the utility tree represents a refinement of the non-functional requirement and ends with leaves. Leaves are scenarios. And this is a good approach from my point of view. A scenario is easier to comprehend for all stakeholders. It is based on the - Context Stimulus Response Pattern – and should lead to a decent understanding what, for instance, security really means for a software product. I will present an example in one of my upcoming posts.