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设计模式-(15)责任链模式 (swift版)

时间:2018-04-29 01:21:05      阅读:264      评论:0      收藏:0      [点我收藏+]

标签:set   uml   rri   alt   leave   enc   解耦   tle   bsp   

一,概念:

  责任链模式(Chain of Responsibility Pattern)为请求创建了一个接收者对象的链。这种模式给予请求的类型,对请求的发送者和接收者进行解耦。这种类型的设计模式属于行为型模式。在这种模式中,通常每个接收者都包含对另一个接收者的引用。如果一个对象不能处理该请求,那么它会把相同的请求传给下一个接收者,依此类推。

  主要解决职责链上的处理者负责处理请求,客户只需要将请求发送到职责链上即可,无须关心请求的处理细节和请求的传递,所以职责链将请求的发送者和请求的处理者解耦了。

二,UML图:

  技术分享图片

  Handler定义一个处理请示的接口;

  ConcreteHandler具体处理者类,处理它所负责的请求,可访问它的后继者,如果可以处理该请求,就处理,否则就将该请求转发给它的后继者。

  Handler 里面聚合它自己,在 HandlerRequest 里判断是否合适,如果没达到条件则向下传递,向谁传递之前 set 进去。

最重要的两点,一个是你需要事先给每个具体管理者设置它的上司是哪个类,也就是设置后继者。另一点就是你需要在每个具体管理者处理请求时,做出判断,是可以处理这个请求,还是必须要“推卸责任”,转移给后继者去处理。

 

三,使用场景:

  1、有多个对象可以处理同一个请求,具体哪个对象处理该请求由运行时刻自动确定。 

  2、在不明确指定接收者的情况下,向多个对象中的一个提交一个请求。 

  3、可动态指定一组对象处理请求。

 

四,代码实例:

struct Leaving {
    var title: String
    var reasone: String
    var from: String
    var position: String
    var leaveDaysNum: Float
    
}

 

protocol Leader {
    var superior: Leader? {get set}
    
    var leaderPosition: String {get set}
    
    var controlLeavingDataTimeMix: Float {get set}
    var controlLeavingDataTimeMax: Float {get set}
    
    func handleLeaving(leaving: Leaving) -> Bool;
}

class CommonLeader: Leader {
    var superior: Leader?
    var leaderPosition: String
    var controlLeavingDataTimeMix: Float
    var controlLeavingDataTimeMax: Float
    
    init(superior: Leader?, position: String, mixTime: Float, maxTime: Float) {
        self.superior = superior
        leaderPosition = position
        controlLeavingDataTimeMax = maxTime
        controlLeavingDataTimeMix = mixTime
    }
    
}

extension Leader{
    func handleLeaving(leaving: Leaving) -> Bool {
        if leaving.leaveDaysNum >= controlLeavingDataTimeMix, leaving.leaveDaysNum <= controlLeavingDataTimeMax {
            print("I‘m \(leaderPosition), I agree!")
            return true
        }else if leaving.leaveDaysNum > controlLeavingDataTimeMax{
            if let superboss = superior{
                print("I‘m \(leaderPosition), Your leave longer than my control,i should ask my superior!")
                return superboss.handleLeaving(leaving: leaving)
            }else{
                print("I‘m \(leaderPosition), Your leave time is too long, I‘m against it")
                return false;
            }
            
        }else{
            print("I‘m \(leaderPosition), you have a problem with leaving time thus can‘t agree with you.")
            return false
        }
    }
}

class TeamLeader: CommonLeader {
    
    init(superior: Leader?) {
        super.init(superior: superior, position: "Team Leader", mixTime: 0.5, maxTime: 1.0)
    }
}

class DepartmentHead: CommonLeader {
    
    init(superior: Leader?) {
        super.init(superior: superior, position: "Department Head", mixTime: 1.5, maxTime: 7.0)
    }
}

class CompanyManager: CommonLeader {
    
    init(superior: Leader?) {
        super.init(superior: superior, position: "Company Manager", mixTime: 7.5, maxTime: 31.0)
    }
}

 

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let leaving = Leaving(title: "I‘d like to have paternity leave.", reasone: "My wife would have a baby in recent days.", from: "Ternence", position: "iOS engineer", leaveDaysNum: 15.0)
        
        let CM = CompanyManager(superior: nil)
        let DH = DepartmentHead(superior: CM)
        let TL = TeamLeader(superior: DH)
        
        print(TL.handleLeaving(leaving: leaving))
    }
}

 

  

 

设计模式-(15)责任链模式 (swift版)

标签:set   uml   rri   alt   leave   enc   解耦   tle   bsp   

原文地址:https://www.cnblogs.com/yangzigege/p/8969883.html

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