SDP04-06例子代码.rar

class Client { private static int index = -1; //定义一个索引来记录当前状态所在位置 private static MementoCaretaker mc = new MementoCaretaker(); public static void main(String args[]) { Chessman chess = new Chessman("车",1,1); play(chess); chess.setY(4); play(chess); chess.setX(5); play(chess); undo(chess,index); undo(chess,index); redo(chess,index); redo(chess,index); } //下棋 public static void play(Chessman chess) { mc.setMemento(chess.save()); //保存备忘录 index ++; System.out.println("棋子" + chess.getLabel() + "当前位置为：" + "第" + chess.getX() + "行" + "第" + chess.getY() + "列。"); } //悔棋 public static void undo(Chessman chess,int i) { System.out.println("******悔棋******"); index --; chess.restore(mc.getMemento(i-1)); //撤销到上一个备忘录 System.out.println("棋子" + chess.getLabel() + "当前位置为：" + "第" + chess.getX() + "行" + "第" + chess.getY() + "列。"); } //撤销悔棋 public static void redo(Chessman chess,int i) { System.out.println("******撤销悔棋******"); index ++; chess.restore(mc.getMemento(i+1)); //恢复到下一个备忘录 System.out.println("棋子" + chess.getLabel() + "当前位置为：" + "第" + chess.getX() + "行" + "第" + chess.getY() + "列。"); } }