Strategy Pattern

04-Strategy_Pattern.playground/Contents.swift

@@ -0,0 +1,108 @@
+//: Playground - noun: a place where people can play
+// Powered by https://maimieng.com from https://github.com/kingcos/Swift-3-Design-Patterns
+
+import UIKit
+
+// 协议
+protocol CashSuper {
+    func acceptCash(_ money: Double) -> Double
+}
+
+// 普通
+struct CashNormal: CashSuper {
+    func acceptCash(_ money: Double) -> Double {
+        return money
+    }
+}
+
+// 打折
+struct CashRebate: CashSuper {
+    let monenyRebate: Double
+
+    init(_ moneyRebate: Double) {
+        self.monenyRebate = moneyRebate
+    }
+
+    func acceptCash(_ money: Double) -> Double {
+        return money * monenyRebate
+    }
+}
+
+// 满减
+struct CashReturn: CashSuper {
+    let moneyCondition: Double
+    let moneyReturn: Double
+
+    init(_ moneyCondition: Double, _ moneyReturn: Double) {
+        self.moneyCondition = moneyCondition
+        self.moneyReturn = moneyReturn
+    }
+
+    func acceptCash(_ money: Double) -> Double {
+        var result = money
+
+        if result >= moneyCondition {
+            result = money - Double(Int(money / moneyCondition)) * moneyReturn
+        }
+        return result
+    }
+}
+
+// 优惠方式
+enum DiscountWays {
+    case byDefault, twentyPersentOff, threeHundredSubOneHundred
+}
+
+struct CashContext {
+    private let cs: CashSuper
+
+    init(_ cs: CashSuper) {
+        self.cs = cs
+    }
+
+    func getResult(_ money: Double) -> Double {
+        return cs.acceptCash(money)
+    }
+}
+
+struct CashContextWithSimpleFactoryPattern {
+    private let cs: CashSuper
+
+    init(_ type: DiscountWays) {
+        switch type {
+        case .twentyPersentOff:
+            cs = CashRebate(0.8)
+        case .threeHundredSubOneHundred:
+            cs = CashReturn(300, 100)
+        default:
+            cs = CashNormal()
+        }
+    }
+
+    func getResult(_ money: Double) -> Double {
+        return cs.acceptCash(money)
+    }
+}
+
+// 策略模式
+var type = DiscountWays.twentyPersentOff
+var cc: CashContext
+switch type {
+case .twentyPersentOff:
+    cc = CashContext(CashRebate(0.8))
+case .threeHundredSubOneHundred:
+    cc = CashContext(CashReturn(300, 100))
+default:
+    cc = CashContext(CashNormal())
+}
+cc.getResult(200)
+
+// 策略模式与简单工厂模式结合
+var cs = CashContextWithSimpleFactoryPattern(.byDefault)
+cs.getResult(100)
+
+cs = CashContextWithSimpleFactoryPattern(.twentyPersentOff)
+cs.getResult(200.5)
+
+cs = CashContextWithSimpleFactoryPattern(.threeHundredSubOneHundred)
+cs.getResult(650)

04-Strategy_Pattern.playground/contents.xcplayground

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='ios'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>

README.md

@@ -22,6 +22,7 @@ If my code did help you, would you please give me a Star 🌟? It will courage m
 1. [Simple Factory Pattern](01-Simple_Factory_Pattern.playground/Contents.swift)
 2. [Factory Method Pattern](02-Factory_Method_Pattern.playground/Contents.swift)
 3. [Abstract Factory Pattern](03-Abstract_Factory_Pattern.playground/Contents.swift)
+4. [Strategy Pattern](04-Strategy_Pattern.playground/Contents.swift)
 
 ## Reference
 

README_CN.md

@@ -22,6 +22,7 @@
 1. [简单工厂模式（Simple Factory Pattern）](01-Simple_Factory_Pattern.playground/Contents.swift)
 2. [工厂方法模式（Factory Method Pattern）](02-Factory_Method_Pattern.playground/Contents.swift)
 3. [抽象工厂模式（Abstract Factory Pattern）](03-Abstract_Factory_Pattern.playground/Contents.swift)
+4. [策略模式（Strategy Pattern）](04-Strategy_Pattern.playground/Contents.swift)
 
 ## 文章