Patterns are reusable solutions to recurring design problems, especially around boundaries, dependencies, and change management. Used well, patterns reduce cognitive load; used blindly, they add accidental complexity. Example: dependency injection is useful when it makes composition and testing simpler, not when it hides control flow.

Architectural Patterns3 notes

Architectural patterns define how a system's components are organized, how data flows between them, and where responsibility boundaries lie.

CQS

A principle where a method either changes state (command) or returns data (query), never both.

CQS

Dependency Injection

A pattern where objects receive dependencies from an external source instead of creating them, a practical form of Inversion of Control.

Dependency Injection

Design Patterns24 notes

23 reusable object-oriented solutions to recurring design problems, giving teams a shared vocabulary for design intent and tradeoffs.

Design Patterns

Event Bus

A centralized publish/subscribe dispatcher where publishers emit events and subscribers register handlers, with neither side knowing the other exists.

Event Bus

Repository & UoW

Repository gives a collection-like interface over domain objects; Unit of Work tracks changes and commits them as one atomic transaction.

Repository & UoW

Resilience Patterns3 notes

Patterns that keep distributed systems stable when dependencies degrade by controlling how failure propagates.

Resilience Patterns

References

Design Patterns: Elements of Reusable Object-Oriented Software — the original Gang of Four catalog, including pattern intent, applicability, structure, consequences, and relationships.
Software design pattern (Wikipedia)

Topics

DEVBOOK

Patterns

References

Architectural Patterns

Resilience Patterns

Design Patterns

Repository & UoW

CQS

Event Bus

Dependency Injection