标签：print enum interface balance context super 图片 rate ext
一，概念：
策略模式定义了一系列的算法，并将每一个算法封装起来，而且使他们可以相互替换，让算法独立于使用它的客户而独立变化。
二，使用场景
1.针对同一类型问题的多种处理方式，仅仅是具体行为有差别时；
2.需要安全地封装多种同一类型的操作时；
3.出现同一抽象类有多个子类，而又需要使用 if-else 或者 switch-case 来选择具体子类时。
三，类图
环境(Context)角色：持有一个Strategy的引用。
抽象策略(Strategy)角色：这是一个抽象角色，通常由一个接口或抽象类实现。此角色给出所有的具体策略类所需的接口。
具体策略(ConcreteStrategy)角色：包装了相关的算法或行为。
四，代码实例
protocol CardInterface {
var money: Float{get set}
var discountShopping: Float{get}
var discountFood: Float{get}
var discountRecreation: Float{get}
func shopping(standardCost: Float) -> Bool
func food(standardCost: Float) -> Bool
func recreation(standardCost: Float) -> Bool
}
class BaseCard: CardInterface {
var money: Float
var discountShopping: Float
var discountFood: Float
var discountRecreation: Float
init(money: Float, dShopping: Float, dFood: Float, dRecreation: Float) {
self.money = money
discountShopping = dShopping
discountFood = dFood
discountRecreation = dRecreation
}
func shopping(standardCost: Float) -> Bool {
if money >= standardCost * discountShopping {
money -= standardCost * discountShopping
print("success: price(\(standardCost)), cost (\(standardCost * discountShopping)) in fact,left (\(money)),type shopping")
return true
}
print("Lack of balance")
return false
}
func food(standardCost: Float) -> Bool {
if money >= standardCost * discountFood {
money -= standardCost * discountFood
print("success: price(\(standardCost)), cost (\(standardCost * discountFood)) in fact,left (\(money)),type food")
return true
}
print("Lack of balance")
return false
}
func recreation(standardCost: Float) -> Bool {
if money >= standardCost * discountRecreation {
money -= standardCost * discountRecreation
print("success: price(\(standardCost)), cost (\(standardCost * discountRecreation)) in fact,left (\(money)),type recreation")
return true
}
print("Lack of balance")
return false
}
}
class NomalCard: BaseCard {
init(money: Float) {
super.init(money: money, dShopping: 0.88, dFood: 0.9, dRecreation: 0.8)
}
}
class VipCard: BaseCard {
init(money: Float) {
super.init(money: money, dShopping: 0.8, dFood: 0.8, dRecreation: 0.7)
}
}
class SuperVipCard: BaseCard {
init(money: Float) {
super.init(money: money, dShopping: 0.7, dFood: 0.75, dRecreation: 0.5)
}
}
enum CardType: String {
case Nomal
case VIP
case SuperVIP
}
class Customer {
var card: CardInterface?
var cardType: CardType
init(cType: CardType) {
cardType = cType
addCard()
}
fileprivate func addCard() {
switch cardType {
case .Nomal:
card = NomalCard(money: 100)
case .VIP:
card = VipCard(money: 100)
case .SuperVIP:
card = SuperVipCard(money: 100)
default: break
}
}
}
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let xiaoMing = Customer(cType: .SuperVIP)
var rel = xiaoMing.card?.recreation(standardCost: 88)
print(rel ?? false)
rel = xiaoMing.card?.recreation(standardCost: 100)
print(rel ?? false)
rel = xiaoMing.card?.recreation(standardCost: 100)
print(rel ?? false)
}
}
标签：print enum interface balance context super 图片 rate ext
原文地址：https://www.cnblogs.com/yangzigege/p/8976055.html
