Section A.3. Ubiquitous Language

A.3. Ubiquitous Language

In Domain Driven Design, Eric Evans [Eva04] discusses the development of "ubiquitous languages" to aid communication about the requirements of systems. The terminology impacts directly on the design of the software.

A ubiquitous language evolves as the understanding of the business needs of the application evolve. This language is reflected directly in the classes, associations, and methods of the software. UML diagrams can help in discussions about the domain, making ongoing links between the business language and the form of the implementation.

Businesspeople and software developers can thus speak a common, evolving language, reducing the need to map between different realms and reducing misunderstandings. Evans suggests that some problems and issues that arise when coding the application are best resolved by addressing the clarity of the current ubiquitous language.

Fit tests are a natural way to help develop this ubiquitous language. Such tests provide a comprehensive bridge between discussions of business need and software design. Writing concrete examples as tests explores ways in which to use and evolve the ubiquitous language for expressing business objects, constraints, and rules.