Topic
Data Manager
The component that owns a domain’s whole conversation with a data store. It presents business-shaped operations and keeps store technology, command construction and fault translation behind its seam.
4 pages
Writing25 September 2026
Clean Abstractions Around Libraries
A library boundary owns the application's contract even when its terms match the library's. It contains provider types, validation, failures, and configuration, and keeps replacement possible.
Writing5 December 2020
Separate State from Behavior? Yes Please!
Separating state from behavior simplifies object-oriented systems: immutable DTOs carry data, while managers compose collaborators and make operations explicit at call sites.
Chapter20 September 2017
Architecture Layers in C#
Structure communicates intent: strict layers from Domain Facade to Gateway, internal by default with a public surface the compiler enforces, and folder depth that marks each class's level of abstraction.
Chapter20 September 2017
Architecture Layers in Python
Structure communicates intent: strict layers from Domain Facade to Gateway, a public surface declared in the boundary __init__.py, and folder depth that marks each class's level of abstraction.