Refactor a God-Object Order Service with Strategy + Command
Overview
What this challenge is about.
Read OrderService and the last 18 months of bug tickets touching it. Author a 5-page design document showing the current class diagram, the target Strategy-per-order-type + Command-per-action diagram, and the migration sequence. Implement a clean module behind a feature flag, migrate the two highest-traffic order types (standard purchase, blanket order) with characterization tests, and verify behavior parity in staging for 72 hours. Deliver the design document, the feature-flagged module, a migration runbook for the remaining 9 order types, and a 1-page maintainability before/after report measuring cyclomatic complexity, file-touch count for a hypothetical new type, and test runtime.
The Brief
What you'll do, and what you'll demonstrate.
Refactor a God-Object OrderService into a Strategy + Command design and migrate two order types end-to-end behind a feature flag.
Earning criteria — what you'll demonstrate
- Apply Strategy + Command patterns to a real legacy God-Object
- Sequence a pattern-based refactor behind a feature flag
- Measure maintainability gains with concrete metrics
- Document a migration so the rest of the team can finish it
Program Fit
Where this fits in your program.
Sharpens the same skills your degree expects you to demonstrate.
Skills
Skills you'll demonstrate.
Each one shows up on your verified credential.
Careers
Roles this prepares you for.
Real titles. Real skill bridges. Pick the one closest to your trajectory.
Career mappings coming soon.