Editing State pattern (section)

{{short description|Software design pattern}}
The '''state pattern''' is a [[Behavioral pattern|behavioral]] [[software design pattern]] that allows an object to alter its behavior when its internal state changes. This pattern is close to the concept of [[finite-state machine]]s. The state pattern can be interpreted as a [[strategy pattern]], which is able to switch a strategy through invocations of methods defined in the pattern's interface.

The state pattern is used in [[computer programming]] to encapsulate varying behavior for the same [[object (computer science)|object]], based on its internal state. This can be a cleaner way for an object to change its behavior at runtime without resorting to conditional statements and thus improve maintainability.<ref name="GOF">{{cite book |author=[[Erich Gamma]] |author2=[[Richard Helm]] |author3=[[Ralph Johnson (computer scientist)|Ralph Johnson]] |author4=[[John M. Vlissides]] |title=Design Patterns: Elements of Reusable Object-Oriented Software |publisher=[[Addison-Wesley]] |year=1995 |isbn=0-201-63361-2|title-link=Design Patterns: Elements of Reusable Object-Oriented Software }}</ref>{{Rp|395}}