Behavioral Done

Author: VamshiIITBHU14

25) Behavioural - Observer Design Pattern.swift

@@ -0,0 +1,94 @@
+import Foundation
+
+protocol Invocable : class
+{
+ func invoke(_ data: Any)
+}
+
+public protocol Disposable
+{
+ func dispose()
+}
+
+public class Event<T>
+{
+ public typealias EventHandler = (T) -> ()
+ 
+ var eventHandlers = [Invocable]()
+ 
+ public func raise(_ data: T)
+ {
+ for handler in eventHandlers
+ {
+ handler.invoke(data)
+ }
+ }
+ 
+ public func addHandler<U: AnyObject>
+ (target: U, handler: @escaping (U) -> EventHandler) -> Disposable
+ {
+ let subscription = Subscription(
+ target: target, handler: handler, event: self)
+ eventHandlers.append(subscription)
+ return subscription
+ }
+}
+
+class Subscription<T: AnyObject, U> : Invocable, Disposable
+{
+ weak var target: T? // note: weak reference!
+ let handler: (T) -> (U) -> ()
+ let event: Event<U>
+ 
+ init(target: T?,
+ handler: @escaping (T) -> (U) -> (),
+ event: Event<U>)
+ {
+ self.target = target
+ self.handler = handler
+ self.event = event
+ }
+ 
+ func invoke(_ data: Any) {
+ if let t = target {
+ handler(t)(data as! U)
+ }
+ }
+ 
+ func dispose()
+ {
+ event.eventHandlers = event.eventHandlers.filter { $0 as AnyObject? !== self }
+ }
+}
+
+class ScoreBoardInTheGround{
+ let batsmenHitRun = Event<Int>()
+ init(){}
+ func updateScore(){
+ 
+ }
+}
+
+class ScoreUpdateInServers{
+ init(){
+ let scoreBoard = ScoreBoardInTheGround()
+ let subscriber = scoreBoard.batsmenHitRun.addHandler(target: self, handler: ScoreUpdateInServers.showScoreInApp)
+ 
+ //simualte batsman hitting runs in the ground
+ scoreBoard.batsmenHitRun.raise(6)
+ 
+ //get rid of the description
+ subscriber.dispose()
+ }
+ 
+ func showScoreInApp(score: Int){
+ print("Score Now is : \(score) runs")
+ }
+}
+
+func main(){
+ let dummy = ScoreUpdateInServers()
+}
+
+main()
+

26) Behavioural - State Design Pattern.swift

@@ -0,0 +1,66 @@
+import UIKit
+
+protocol State {
+ func isSold(playerAuction: PlayerAuction) -> Bool
+ func whichTeam(playerAuction: PlayerAuction) -> String?
+}
+
+class PlayerAuction {
+ private var state: State = IsUnsoldState()
+ 
+ var isSold: Bool {
+ get {
+ return state.isSold(playerAuction: self)
+ }
+ }
+ 
+ var teamName: String? {
+ get {
+ return state.whichTeam(playerAuction: self)
+ }
+ }
+ 
+ func changeStateToSold(teamName: String) {
+ state = IsSoldState(teamName: teamName)
+ 
+ }
+ 
+ func changeStateToUnSold() {
+ state = IsUnsoldState()
+ }
+ 
+}
+
+
+
+class IsUnsoldState: State {
+ func isSold(playerAuction: PlayerAuction) -> Bool { return false }
+ 
+ func whichTeam(playerAuction: PlayerAuction) -> String? { return nil }
+}
+
+class IsSoldState: State {
+ let teamName: String
+ 
+ init(teamName: String) {
+ self.teamName = teamName
+ }
+ 
+ func isSold(playerAuction: PlayerAuction) -> Bool {
+ return true
+ }
+ 
+ func whichTeam(playerAuction: PlayerAuction) -> String? {
+ return teamName
+ }
+}
+
+func main(){
+ let playerAuction = PlayerAuction()
+ print(playerAuction.isSold, playerAuction.teamName)
+ playerAuction.changeStateToSold(teamName: "Chennai Super Kings")
+ print(playerAuction.isSold, playerAuction.teamName!)
+}
+
+main()
+

27) Behavioural - Template Design Pattern.swift

@@ -0,0 +1,86 @@
+import UIKit
+import Foundation
+
+class TeamTemplate{
+ func buildTeam(){
+ pickBatsmen()
+ pickBowlers()
+ pickAllRounders()
+ pickWicketKeeper()
+ print("\nTeam Set For the match")
+ }
+ 
+ func pickBatsmen(){
+ 
+ }
+ 
+ func pickBowlers(){
+ 
+ }
+ 
+ func pickAllRounders(){
+ 
+ }
+ 
+ private func pickWicketKeeper(){
+ print("Only one WK avaialable and he is picked by default")
+ }
+}
+
+class SeamingPitchTeamTemplate : TeamTemplate{
+ override func pickBatsmen() {
+ print("Picking 6 batsmen")
+ }
+ 
+ override func pickBowlers() {
+ print("Picking 3 Fast Bowlers")
+ }
+ 
+ override func pickAllRounders() {
+ print("Picking 1 Pace AllRounder")
+ }
+}
+
+class SpinPitchTeamTemplate : TeamTemplate{
+ override func pickBatsmen() {
+ print("Picking 5 Batsmen")
+ }
+ 
+ override func pickBowlers() {
+ print("Picking 2 Fast Bowlers and 2 Spinners")
+ }
+ 
+ override func pickAllRounders() {
+ print("Picking 2 Spin AllRounder")
+ }
+}
+
+class BattingPitchTeamTemplate : TeamTemplate{
+ override func pickBatsmen() {
+ print("Picking 7 Batsmen")
+ }
+ 
+ override func pickBowlers() {
+ print("Picking 2 Fast Bowlers and 1 Spinners")
+ }
+ 
+ override func pickAllRounders() {
+ print("Picking 1 Batting AllRounder")
+ }
+}
+
+func main(){
+ var finalTeam : TeamTemplate = SeamingPitchTeamTemplate()
+ finalTeam.buildTeam()
+ 
+ print("\n***Pitch Changed***\n")
+ finalTeam = SpinPitchTeamTemplate()
+ finalTeam.buildTeam()
+ 
+ print("\n***Pitch Changed***\n")
+ finalTeam = BattingPitchTeamTemplate()
+ finalTeam.buildTeam()
+}
+
+main()
+

28) Behavioural - Visitor Design Pattern.swift

@@ -0,0 +1,106 @@
+import Foundation
+import UIKit
+
+protocol CricketAccessory{
+ func accept(counter : CheckoutCounter) -> Int
+}
+
+class CricketBat : CricketAccessory{
+ private var price : Double
+ private var brand : String
+ 
+ init(_ price : Double, _ brand:String) {
+ self.price = price
+ self.brand = brand
+ }
+ 
+ public func getPrice() -> Double{
+ return price
+ }
+ 
+ public func getBrand() -> String{
+ return brand
+ }
+ func accept(counter : CheckoutCounter) -> Int {
+ return counter.moveToCounter(bat: self)
+ }
+}
+
+class CricketBall : CricketAccessory{
+ 
+ private var type : String
+ private var price : Double
+ 
+ init(_ type : String, _ price : Double){
+ self.type = type
+ self.price = price
+ 
+ }
+ 
+ public func getType() -> String{
+ return type
+ }
+ 
+ public func getPrice() -> Double{
+ return price
+ }
+ 
+ func accept(counter : CheckoutCounter) -> Int {
+ return counter.moveToCounter(ball: self)
+ }
+ 
+}
+
+protocol CheckoutCounter {
+ func moveToCounter(bat : CricketBat) -> Int
+ func moveToCounter(ball : CricketBall) -> Int
+}
+
+class CashCounter :CheckoutCounter{
+ func moveToCounter(bat: CricketBat) -> Int {
+ var cost : Int = 0
+ if bat.getBrand() == "Brittania"{
+ cost = Int(0.8 * bat.getPrice())
+ } else{
+ cost = Int(bat.getPrice())
+ }
+ print("Bat brand : \(bat.getBrand()) and price is : \(cost) ")
+ return cost
+ }
+ 
+ func moveToCounter(ball: CricketBall) -> Int {
+ 
+ print("Ball Type : \(ball.getType()) and price is : \(ball.getPrice()) ")
+ return Int(ball.getPrice())
+ }
+}
+
+
+func main(){
+ print("Main")
+ func finalPriceCalculation(accessories : [CricketAccessory]) -> Int{
+ var checkout = CashCounter()
+ var cost = 0
+ for item in accessories{
+ cost += item.accept(counter: checkout)
+ }
+ print("Toal cart value : \(cost)")
+ return cost
+ }
+ 
+ var cartItems = [CricketAccessory]()
+ let mrfBat = CricketBat(2000, "MRF")
+ let brittaniaBat = CricketBat(1500, "Brittania")
+ let tennisBall = CricketBall("Tennis", 120)
+ let leatherBall = CricketBall("Leather", 200)
+ cartItems.append(mrfBat)
+ cartItems.append(brittaniaBat)
+ cartItems.append(tennisBall)
+ cartItems.append(leatherBall)
+ 
+ var cost = finalPriceCalculation(accessories: cartItems)
+ print("Checked Out with Bill Amount : \(cost)")
+}
+
+main()
+