State

Usage

• Also known as: Objects for States
• Alters an object's behavior when its state changes
• The object will appear to change its class

Diagram

Participants

Context

• Defines the interface of interest to clients
• Maintains an instance of a ConcreteState subclass that defines the current state

State

• Defines an interface for encapsulating the behavior associated with a particular state of the Context

ConcreteState

• Each subclass implements a behavior associated with a state of Context