Use Real-Time Trading System Implementation to compare familiar Java design-pattern habits with smaller Clojure shapes built from data, functions, namespaces, protocols, and explicit boundaries.
This section turns Real-Time Trading System Implementation into concrete design checkpoints for Java engineers moving toward idiomatic Clojure. Treat the child pages as refactoring lenses: keep the useful design intent, then choose the smallest Clojure mechanism that makes the boundary explicit.
| Checkpoint | Java instinct to question | Clojure move to practice |
|---|---|---|
| Representation | Introduce a class, interface, or pattern role before the data shape is clear | Start with immutable data and named transformations |
| Extension | Add hierarchy, listeners, factories, or wrappers for variation | Use functions, maps, protocols, multimethods, or namespaces at explicit seams |
| Effects | Hide I/O, state, or lifecycle behind object identity | Push effects to narrow edges and keep the core easy to test at the REPL |
Work through these pages in order when refactoring an existing Java design. For new Clojure code, start with the simplest data flow that passes tests; add abstraction only when call sites repeat the same boundary.