Command Pattern

Kind: pattern

Layer: Design Patterns Core

Aliases: Action Pattern

Record: architecture:command-pattern

Severity: recommended

Scope: behavior, invocation, workflow

Canonical: Ontology

A design pattern that wraps a request in an object, so it can be queued, deferred or undone.

Listed in Architecture principles, after Mediator Pattern and before State Pattern.

Requires

• Encapsulation

Reinforces

• Open/Closed Principle (OCP)
• Single Responsibility Principle (SRP)

Enables

• Undo/Redo
• Deferred Execution
• Deferred Execution

Conflicts with

• Direct Method Invocation

In tension with

• Simplicity

Tensions

• Command Pattern / Simplicity

Violated by

• Direct Method Invocation

Severity

• recommended

Category

• Behavioral Patterns

Linked from

• Core Modular Design
• SOLID / Object-Oriented Design
• Behavioral Patterns
• Core Vocabulary
• Quality Attributes
• Severity levels
• The resolutions