Design mode-(14) Decorator mode (Swift version)

One, the concept

Decorator Mode (Decorator): Dynamically adds some additional responsibilities to an object, and to extend the functionality of an object, adorners provide a more resilient alternative than inheritance.

Multiple combinations, less inheritance

Two, UML diagram

　　

　　

Abstract Component Class (Component): An abstract interface is given to standardize the objects that are ready to receive additional responsibilities

Concrete Component Class (Concretecomponent): Defines a specific class that is prepared to accept additional responsibilities, which must implement the component interface.

Decorator Class (Decorator): Holds an instance of a component (Conponent) object and defines an interface that is consistent with the abstract component.

Specific decorator Class (concrete Decoratator): Defines the "affixed" additional responsibility to the Component object.

Third, use case

　　

Protocol Component {    func display (), Void;} Class Componentdecorator:component {        var component:component    var border:string?        Init (component:component) {        self.component = component    }        func display () {        component.display ()    } }

Class Listview:component {        var name:string = "ListView"        func display () {        print (name)    }}class boxview:component {        var name:string = "Boxview"        func display () {        print (name)    }}

Class Blackboder:componentdecorator {        override init (component:component) {        super.init (component:component)        border = "Black"    }        Override func display () {        setborder ()        super.display ()    }        func SetBorder () {        print ("This border is \ (Border?? "Default")    }    }class yellowboder:componentdecorator {        override init (component:component) {        Super.init (component:component)        border = "Yellow"    }        override func display () {        setborder ()        Super.display ()    }        func SetBorder () {        print ("This border is \ (border??") Default ")    }    }

Client side:

Class Viewcontroller:uiviewcontroller {    override func Viewdidload () {        super.viewdidload () let        component = ListView () let        componentb = Yellowboder (component:component)        componentb.display ()}    }

Design mode-(14) Decorator mode (Swift version)