备忘录模式—悔棋操作

备忘录模式—悔棋操作"/>

备忘录模式—悔棋操作

备忘录：在不破坏封装性的前提下，捕获一个对象的内部状态，并在该对象之外保存这个状态。这样以后就可将该对象恢复到原先保存的状态。

通俗的讲就像课本举得例子：一般玩单机游戏都会有存档这个选项，这就可以利用备忘录模式来实现；一些撤销，悔棋操作，都是回到之前的状态。

下面来说一下象棋中的悔棋操作如何利用备忘录模式来实现。

package 象棋悔棋操作;public class GameRole {private String name;private int x;private int y;public String getName() {return name;}public void setName(String name) {this.name = name;}public int getX() {return x;}public void setX(int x) {this.x = x;}public int getY() {return y;}public void setY(int y) {this.y = y;}public void StateDisplay() {System.out.println("这颗棋子的信息:"+this.name+"("+this.x+","+this.y+")");}public void GetInitState() {this.name="马";this.x=2;this.y=1;}public void Run1() {this.name="马";this.x=1;this.y=2;}public void Run2() {this.name="马";this.x=3;this.y=2;}public void Run3() {this.name="马";this.x=4;this.y=1;}public RoleStateMemento SaveState() {return (new RoleStateMemento(name,x,y));}public void RecoveryState(RoleStateMemento memento) {this.name=memento.getName();this.x=memento.getX();this.y=memento.getY();}}package 象棋悔棋操作;public class RoleStateMemento {private String name;private int x;private int y;public RoleStateMemento(String name, int x, int y) {super();this.name = name;this.x = x;this.y = y;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getX() {return x;}public void setX(int x) {this.x = x;}public int getY() {return y;}public void setY(int y) {this.y = y;}}package 象棋悔棋操作;public class RoleStateCaretaker {private RoleStateMemento memento;public RoleStateMemento getMemento() {return memento;}public void setMemento(RoleStateMemento memento) {this.memento = memento;}}package 象棋悔棋操作;public class Test {public static void main(String[] args) {System.out.println("开始时棋子的位置：");GameRole a1=new GameRole();a1.GetInitState();a1.StateDisplay();RoleStateCaretaker stateAdmin=new RoleStateCaretaker();stateAdmin.setMemento(a1.SaveState());System.out.println("移动后棋子的位置：");a1.Run1();a1.StateDisplay();System.out.println("悔棋后棋子的位置：");a1.RecoveryState(stateAdmin.getMemento());a1.StateDisplay();// TODO Auto-generated method stub}}

运行结果：

uml图：