package com.linewell.modeldesgin.memento
import scala.collection.mutable.ArrayBuffer
/**
* 备忘录模式,在command模式中简单实现过一次
* 原发器:象棋类
* Created by ctao on 2015/9/1.
* @param label 标签
* @param x x坐标
* @param y y坐标
*/
case class Chessman(var label: String, var x: Int, var y: Int) extends ChessmanFunction {
/**
* 保存状态
* @return 备忘录
*/
def save: ChessMemento = ChessMemento(this.label, this.x, this.y)
/**
* 恢复状态
* @param chessMemento 备忘录
*/
def restore(chessMemento: ChessMemento): Unit = {
label = chessMemento.label
x = chessMemento.x
y = chessMemento.y
}
}
/**
* 备忘录样例类
* @param label 标签
* @param x x坐标
* @param y y坐标
*/
case class ChessMemento(label: String, x: Int, y: Int)
/**
* 下棋方法特质
*/
trait ChessmanFunction {
/**
* 存放多个备忘录
*/
private var mementoArrayBuffer = new ArrayBuffer[ChessMemento]()
/**
* 定义初始位置索引
*/
private var index = -1
/**
* 设置备忘录
* @param memento 备忘录
*/
def setMemento(memento: ChessMemento): Unit = mementoArrayBuffer += memento
/**
* 下棋
* @param chessman 棋子
*/
def play(chessman: Chessman): Unit = {
setMemento(chessman.save)
index += 1
println(s"棋子${chessman.label} 当前位置为第${chessman.x}行,第${chessman.y}列")
}
/**
* 悔棋
* @param chessman 棋子
*/
def undo(chessman: Chessman): Unit = {
println("******悔棋******")
index match {
case -1 => println("已经在最初位置,无法撤销")
case 0 => index -= 1
println("已经在最初位置,无法撤销")
case length: Int if length > 0 => index -= 1
chessman.restore(mementoArrayBuffer(index))
println(s"棋子${chessman.label} 当前位置为第${chessman.x}行,第${chessman.y}列")
case _ => println("出现异常")
}
}
/**
* 撤销悔棋
* @param chessman 棋子
*/
def redo(chessman: Chessman): Unit = {
println("******撤销悔棋******")
index match {
case -1 => index = 1
chessman.restore(mementoArrayBuffer(index))
println(s"棋子${chessman.label} 当前位置为第${chessman.x}行,第${chessman.y}列")
case length: Int if -1 < length && length < mementoArrayBuffer.length - 1 => index += 1
chessman.restore(mementoArrayBuffer(index))
println(s"棋子${chessman.label} 当前位置为第${chessman.x}行,第${chessman.y}列")
case length: Int if length >= mementoArrayBuffer.length - 1 => println("已经在最终位置,无法恢复")
case _ => println(s"异常$index")
}
}
}
package com.linewell.modeldesgin.memento
/**
* 测试客户端
* Created by ctao on 2015/9/1.
*/
object Client extends App {
val chess = new Chessman("马",1,1)
chess.undo(chess)
chess.play(chess)
chess.y = 4
chess.play(chess)
chess.x = 5
chess.play(chess)
chess.undo(chess)
chess.undo(chess)
chess.undo(chess)
chess.redo(chess)
chess.redo(chess)
chess.redo(chess)
chess.redo(chess)
chess.undo(chess)
chess.undo(chess)
chess.undo(chess)
chess.undo(chess)
chess.undo(chess)
chess.redo(chess)
}
scala实现备忘录模式
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转载自cjuexuan.iteye.com/blog/2240123
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