Pattern Vocabulary Cheat Sheet

Introduction

Pattern vocabulary cheat sheet — print, fold, review before senior interviews. Each entry: name → intent → smell → production example. No UML, no boilerplate — only vocabulary that compounds in design meetings.

The story

Candidate kept 1-page cheat sheet pinned 6 months. Five minutes before every design meeting. At promotion review she was the "what should we call this?" engineer. Vocabulary compounds.

The business problem

Teams without shared vocabulary debate implementation instead of intent:

• Duplicate abstractions: same pattern, different names per team.
• Review friction: can't discuss trade-offs without shared terms.
• Interview gap: recognize pattern in code but can't name it.
• ADR quality: "added interface" vs "Repository at persistence seam."

The problem teams faced

Cheat sheet covers:

• GoF creational, structural, behavioral — intent + smell each.
• Enterprise patterns — Saga, Outbox, CQRS, Gateway, BFF, Strangler.
• Meta — when NOT to use; refactoring to patterns.
• Quick composition refs — checkout, notifications, payments.

Understanding the topic

Intent: Fast recall of pattern vocabulary for interviews and reviews.

• Intent — one sentence what it solves.
• Smell — what triggers considering it.
• Example — one production anchor.
• Skip when — one-line when-not.

Internal architecture

Sample cheat sheet entries:

Strategy     | Swappable algorithms        | Long switch on type      | Shipping modes
Repository   | Persistence seam            | SQL in domain            | OrderRepo port
Saga         | Distributed transaction     | Multi-service workflow   | Checkout place order
Outbox       | Reliable event publish      | Dual-write failure       | OrderPlaced → Kafka
Circuit Brkr | Stop calling dead dependency| Cascade timeout          | Payment API
Adapter      | Foreign interface wrapper   | Legacy SDK vocabulary    | SOAP payment
When NOT     | Skip if 1 impl, prototype   | Hypothetical variant     | YAGNI / Rule of Three

Visual explanation

Three diagrams organize vocabulary by category and composition:

Informative example

Recite drill — Observer:

NAME:    Observer (behavioral)
INTENT:  Notify dependents when subject state changes
SMELL:   "When X happens, also update A, B, C" scattered in code
EXAMPLE: OrderPlaced → email + inventory + analytics (in-process)
SKIP:    Cross-service sync coupling — use Outbox + async bus instead
STORY:   Notification rebuild — 47 if-branches → Observer + Strategy

Execution workflow

Real-world use

Staff engineers' printed reference cards; team pattern glossaries in Confluence; ADR templates with pattern name field.

Production case study

6-month cheat sheet habit:

• Practice: 5 min before every design meeting.
• Outcome: team consultant for pattern naming at promotion review.
• Lesson: vocabulary compounds — not cramming.

Trade-offs

• Pro: fast recall; shared team language; interview confidence.
• Con: cheat sheet ≠ deep understanding — pair with stories.

Decision framework

• Smell → name → confirm force → apply or skip.
• If can't name smell, probably don't need pattern yet.

Best practices

• Handwrite your production example on printed sheet.
• Include "when NOT" row for top 10 patterns.
• Update sheet when you remove a pattern — deletion entries.

Anti-patterns to avoid

• Cramming night before without stories — hollow recall.
• Using cheat sheet terms without knowing trade-offs.

Common mistakes

• Confusing similar patterns — Decorator vs Proxy vs Adapter.

Debugging tips

• Decorator adds behavior; Adapter changes interface; Proxy controls access.

Optimization strategies

• 10 patterns you know deeply > 40 patterns shallowly.

Common misconceptions

• Cheat sheet ≠ silver bullet — vocabulary enables judgment conversations.
• Enterprise patterns are interview vocabulary too — not just GoF.

Advanced interview questions

Summary

You have a one-page mental model for fast pattern recall. Print the sheet, add your stories, review before interviews — you own Pattern Vocabulary and Interview Mastery.