Bottom-up Architecture: Bridging the Architecture-Code Gap • Oliver Drotbohm • GOTO 2024

Architecture and code exist at different levels of abstraction - architecture deals with high-level concepts and modules while code is very specific with classes and methods

Architecturally evident code expresses architectural ideas and design intent directly in the codebase through type systems, annotations, and naming conventions

Tools like JQAssistant, ArcUnit and jMolecules help bridge the architecture-code gap by:

• Identifying architectural concepts in code
• Verifying architectural rules
• Generating documentation
• Enabling testability

DDD tactical patterns (aggregates, value objects, repositories) can be expressed in code using annotations and type systems to enforce architectural rules

Package structures and modules can be used to implement architectural patterns like onion/hexagonal architecture while maintaining testability and separation of concerns

Spring Boot and Spring Framework provide mechanisms to implement architectural concepts through stereotypes, module conventions and testing slices

Moving architectural concepts into code helps with:

• Documentation that stays current
• Compile-time verification
• Onboarding new team members
• Making architecture more maintainable

Tools should support gradual adoption in existing codebases rather than requiring full rewrites

Architecture should be expressed through stronger means than just naming conventions - using type systems and compile-time verification

Focus should be on making architectural abstractions workable and usable in application code rather than just theoretical concepts