Interface Segregation Principle

ISP

Kind: principle

Layer: Structural Core

Aliases: ISP, Interface Segregation Principle

Record: architecture:interface-segregation

Severity: mandatory

Scope: interface, service, module

Canonical: Ontology

A design rule that a client depends on an interface holding only the methods it uses.

Listed in Architecture principles, after Autonomy and before Dependency Inversion Principle (DIP).

Requires

• Role-Specific Interfaces

Reinforces

• Single Responsibility Principle (SRP)
• Low Coupling

Enables

• Consumer-Specific Contracts

Conflicts with

• Fat Interface
• Repository Dump

In tension with

• Interface Proliferation

Tensions

• Interface Segregation Principle (ISP) / Interface Proliferation

Violated by

• Fat Interface

Refactored by

• Split Interface
• Extract Role Interface

Severity

• mandatory

Category

• SOLID / Object-Oriented Design

Linked from

• The structural domain
• Anti-patterns
• Core Modular Design
• SOLID / Object-Oriented Design
• Severity levels
• The resolutions