备忘录模式(Memento)

/** Memento */
class Memento {
    var checkPoint = 0
    var lifeValue = 0
    var weapon = ""
}

/** Originator */
class CallOfDuty {
    var checkPoint = 1
    var lifeValue = 100
    var weapon = "沙漠之鹰"

    fun play() {
        println("玩游戏 : 第${checkPoint}关 奋战杀敌中")

        lifeValue -= 10

        println("进度升级了")

        checkPoint++

        println("到达 第${checkPoint}关")
    }

    fun quit() {
        println(" ---------------------- ")
        println("退出前的游戏属性 : ${toString()}")
        println(" ---------------------- ")
    }

    fun createMemento() : Memento {
        return Memento().apply {
            this.checkPoint = this@CallOfDuty.checkPoint
            this.lifeValue = this@CallOfDuty.lifeValue
            this.weapon = this@CallOfDuty.weapon
        }
    }

    fun restore(memento: Memento) {
        memento.run {
            this@CallOfDuty.checkPoint = this.checkPoint
            this@CallOfDuty.lifeValue = this.lifeValue
            this@CallOfDuty.weapon = this.weapon
        }
    }

    override fun toString(): String {
        return "CallOfDuty(checkPoint=$checkPoint, lifeValue=$lifeValue, weapon='$weapon')"
    }
}

/** Caretaker */
class Caretaker {
    private var memento: Memento? = null

    fun archive(memento: Memento) {
        this@Caretaker.memento = memento
    }

    fun getMemento() : Memento = memento!!
}

fun main(args: Array<String>) {
    val game = CallOfDuty()
    game.play()

    val caretaker = Caretaker()
    caretaker.archive(game.createMemento())

    game.quit()

    val newGame = CallOfDuty()
    newGame.restore(caretaker.getMemento())
    newGame.play()
    newGame.quit()
}