Use of swift protocol

//
//  Protocols.swift
//  SwiftCode
//
//  Created by Alisa on 2022/4/14.
//  Copyright  2022 Alisa. All rights reserved.
//

import Foundation

/*
 
     agreement ： In grammar , Some properties and methods can be defined in the protocol , These properties and methods are just declarations , These properties and methods cannot be implemented in the protocol . The protocol is not a data type , No, 
          Construction method , No instantiation is required 
 
    swift in , Agreement to use protocol Keyword creation , Which can declare properties and methods , The attribute can be a calculation attribute in the concrete implementation , It can also be a storage attribute 
 
     Combination of protocol and extension ：
         Extensions can add new functions to data types , Through extension, you can also provide a default implementation for the attribute methods agreed in the protocol .
         Developers can provide an extension to a protocol , Provide a set of default implementation for its agreed attribute methods in the extension , In this way, all data types that comply with this protocol get the default implementation in the extension 
*/

protocol BookMarkProtocol{
    
    /* **  Defining attributes  */
    // read-only 
    var bookColor:String { get }
    // Can read but write 
    var bookPages:Int {get set}
    // Static attribute 
    static var bookSize:(Int, Int){get set}
    
    /* **  Define methods  */
    // Example method 
    func markLiteraryBooks()->Void
    // Static methods 
    static func cleanBookMark()->Void
}

class Bookmark{
    
    var bookName:String
    var Bentence:String
    
    var color:String
    var pages:Int
    static var size:(Int, Int) = (20, 20)
    
    
    // Protocol attribute 
    // read-only 
    var bookColor:String{
        get{
            return self.color
        }
    }
    // Can read but write 
    var bookPages:Int{
        get{
            print(" Instance calculation properties of the protocol , Read book Of pages：\(self.pages)")
            return self.pages
        }
        set{
            print(" Instance calculation properties of the protocol , Set up book Of pages：\(newValue)")
            self.pages = newValue
        }
    }
    // Static attribute 
    static var bookSize:(Int, Int){
        get{
            print(" Static computing properties of the protocol , Read book Of size：\(self.size)")
            return self.size
        }
        set{
            print(" Static computing properties of the protocol , Set up book Of size:\(newValue)")
            self.size = newValue
        }
    }
    
    
    // Protocol method 
    // Example method 
    func markLiteraryBooks(){
        print(" Put in literature books  book mark")
    }
    // Static methods 
    static func cleanBookMark(){
        print(" Clean up the current  book mark")
    }
    
    init() {
        self.bookName = ""
        self.Bentence = ""
        
        // Protocol added properties 
        self.color = ""
        self.pages = 0
    }
    
    deinit{
        print("Bookmark deinit")
    }
}

// The combination of protocol and extension 
@objc protocol ClassProcotol:AnyObject{
    // This protocol method can choose whether to implement , That is, classes that comply with the protocol can implement , It can also not be realized 
    @objc optional func log()
}
// by ClassProtocol The method in provides a default implementation 
extension ClassProcotol{
    func log(){
        print("show this log")
    }
}
class AirConditioner:ClassProcotol{
    
    // When accepting this Agreement , There was a warning ：Non-'@objc' method 'log()' does not satisfy optional requirement of '@objc' protocol 'ClassProcotol'
}

class Protocols{
    
    // Use instance properties and instance methods in the protocol 
    func useInstanceProtocols(){
        
        let mark = Bookmark()
        // Set the calculation properties in the protocol 
        mark.bookPages = 22
        // Set properties 
        mark.color = "blue"
        
        // Read the calculation properties in the protocol 
        let color = mark.bookColor
        let pages = mark.bookPages
        
        print(" The color of the current book ：\(color),  The number of pages in the current book ：\(pages)")
        
        // Instance method in protocol 
        mark.markLiteraryBooks()
        
        /*  Print information ：
          Instance calculation properties of the protocol , Set up book Of pages：22
          Instance calculation properties of the protocol , Read book Of pages：22
          The color of the current book ：blue,  The number of pages in the current book ：22
          Put in literature books  book mark
         Bookmark deinit
        */
    }
    
    // Use static properties and static methods in the protocol 
    func useStaticProtocols(){
        
        // Static properties in the protocol 
        let size = Bookmark.bookSize
        print("size Standard size of ：\(size)")
        
        // Static methods in the protocol 
        Bookmark.cleanBookMark()
        
        /*  Print information 
         size Standard size of ：(20, 20)
          Clean up the current  book mark
        */
    }
    
    // The combination of protocol and extension 
    func useExtensionProtocols(){
        
        let acd = AirConditioner()
        acd.log()   //show this log
        
    }
}