Low Coupling

Kind: quality-attribute

Layer: Structural Core

Aliases: Loose Coupling, Decoupling

Record: architecture:low-coupling

Severity: mandatory

Scope: module, component, service

Canonical: Ontology

The degree to which a module can change without forcing changes in the modules around it.

Listed in Architecture principles, after High Cohesion and before Encapsulation.

Requires

• Abstraction
• Stable Interfaces

Reinforces

• Modularity
• Replaceability
• Portability

Enables

• Independent Deployment
• Independent Testing

Conflicts with

• Tight Coupling
• Circular Dependency
• Inappropriate Intimacy
• Message Chain

In tension with

• Runtime Indirection

Tensions

• Low Coupling / Runtime Indirection

Violated by

• Tight Coupling
• Circular Dependency

Refactored by

• Extract Interface
• Dependency Injection
• Extract Adapter

Severity

• mandatory

Category

• Core Modular Design

Reinforced by

• Anti-Corruption Layer
• Encapsulation
• Information Hiding
• Composition Over Inheritance
• Interface Segregation Principle
• Dependency Inversion Principle
• Event-Driven Architecture
• Publish/Subscribe Pattern
• Message Broker
• Asynchronous Communication
• Mediator Pattern
• Service-Oriented Architecture

Required by

• Testability
• Composability
• Independence

Linked from

• Node design
• A system is a graph
• Principles are typed
• Debt and leverage
• Anti-patterns
• Domain Architecture
• Contracts / Interfaces / Compatibility
• Correctness / Determinism / Verification
• Portability / Infrastructure / Deployment
• Core Modular Design
• SOLID / Object-Oriented Design
• Event / Messaging / Asynchronous Architecture
• Error Handling / Resilience
• Behavioral Patterns
• Scalability / Performance / Optimization
• Codebase / System Architecture Styles
• Codebase / System Architecture Styles
• Core Modular Design
• Core Vocabulary
• SOLID / Object-Oriented Design
• Severity levels
• The resolutions