Writing
One Order, Every Obligation
One ordering scenario verifies the caller result, stored lines, fulfillment, and confirmation. Follow its complete C# test, independent observations, and accumulated failure reports.
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.
8 pages
Writing
Refusals, Failures, and Work Still Owed
Failure timing determines what an order still owes. Verify refusal, real transaction rollback, post-commit action failures, and accepted effects whose completion could not be recorded.
Writing
Programming to Exceptions, Part 2: Diagnostics and Boundaries
Specific exceptions preserve failure meaning, causes, and context. A shallow C# hierarchy, Gateway translation, and middleware enrichment carry diagnostic records across service boundaries.
Writing
Programming to Exceptions, Part 1: Method Contracts and Failure
Method contracts let callers rely on completed work and let failures propagate. C# examples distinguish retrieval from search, validate domain entry points, and assign handling to its owner.
Writing
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.
Chapter
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.
Chapter
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.
PWI
Architecture with Intent
The Domain Facade exposes business operations while internal classes call one level down. Managers orchestrate workflows and own configuration and service boundaries.