26.设计模式.备忘录模式(Memento).pptx

1、设计模式(Design Pattern),张凯 副教授 计算机学院 软件工程系,问题(Problem),问题(Problem),问题(Problem),问题(Problem),问题(Problem),问题(Problem),我要保存游戏进度 游戏角色，生命力、攻击力、防御力 模拟战斗代码，读取进度,问题(Problem),class GameRole /生命力 private int vit; public int Vitality get return vit; set vit = value; /攻击力 private int atk; public int Attack get retu

2、rn atk; set atk = value; /防御力 private int def; public int Defense get return def; set def = value; ,/状态显示 public void StateDisplay() Console.WriteLine(角色当前状态：); Console.WriteLine(体力：0, this.vit); Console.WriteLine(攻击力：0, this.atk); Console.WriteLine(防御力：0, this.def); Console.WriteLine(); /获得初始状态 pub

3、lic void GetInitState() this.vit = 100; this.atk = 100; this.def = 100; /战斗 public void Fight() this.vit = 0; this.atk = 0; this.def = 0; ,问题(Problem),static void Main(string args) /大战Boss前 GameRole lixiaoyao = new GameRole(); lixiaoyao.GetInitState(); lixiaoyao.StateDisplay(); /保存进度 GameRole backup

4、 = new GameRole(); backup.Vitality = lixiaoyao.Vitality; backup.Attack = lixiaoyao.Attack; backup.Defense = lixiaoyao.Defense; /大战Boss时，损耗严重 lixiaoyao.Fight(); lixiaoyao.StateDisplay(); /恢复之前状态 lixiaoyao.Vitality = backup.Vitality; lixiaoyao.Attack = backup.Attack; lixiaoyao.Defense = backup.Defense

5、; lixiaoyao.StateDisplay(); Console.Read(); ,主要内容,备忘录模式(Memento),模式动机 模式名称：备忘录模式(Memento) 在应用软件的开发过程中，有时我们有必要记录一个对象的内部状态。为了允许用户取消不确定的操作或从错误中恢复过来，需要实现备份点和撤销机制，而要实现这些机制，我们必须事先将状态信息保存在某处，这样状态才能将对象恢复到它们原先的状态。,备忘录模式(Memento),模式动机 但是对象通常封装了其部分或所有的状态信息，使得其状态不能被其它对象访问，也就不可能在该对象之外保存其状态，而暴露其内部状态又将违反封装的原则，可能有损

6、系统的可靠性和可扩展性。,备忘录模式(Memento),模式定义 备忘录模式(Memento Pattern)：在不破坏封装的前提下，捕获一个对象的内部状态，并在该对象之外保存这个状态，这样可以在以后将对象恢复到原先保存的状态。,备忘录模式(Memento),备忘录模式(Memento),class GameRole /保存角色状态 public RoleStateMemento SaveState() return (new RoleStateMemento(vit, atk, def); /恢复角色状态 public void RecoveryState(RoleStateMemento

7、memento) this.vit = memento.Vitality; this.atk = memento.Attack; this.def = memento.Defense; ,备忘录模式(Memento),class RoleStateMemento /角色状态存储箱 private int vit; private int atk; private int def; public RoleStateMemento(int vit, int atk, int def) this.vit = vit; this.atk = atk; this.def = def; public in

8、t Vitality /生命力 get return vit; set vit = value; public int Attack /攻击力 get return atk; set atk = value; public int Defense /防御力 get return def; set def = value; ,备忘录模式(Memento),/角色状态管理者 class RoleStateCaretaker private RoleStateMemento memento; public void ImportState(RoleStateMemento Record) memen

9、to = Record; public RoleStateMemento ExportState() return memento; ,备忘录模式(Memento),static void Main(string args) /大战Boss前 GameRole lixiaoyao = new GameRole(); lixiaoyao.GetInitState(); lixiaoyao.StateDisplay(); /保存进度 RoleStateCaretaker stateAdmin = new RoleStateCaretaker(); stateAdmin.ImportState(li

10、xiaoyao.SaveState(); /大战Boss时，损耗严重 lixiaoyao.Fight(); lixiaoyao.StateDisplay(); /恢复之前状态 lixiaoyao.RecoveryState(stateAdmin.ExportState(); lixiaoyao.StateDisplay(); Console.Read(); ,备忘录模式(Memento),模式结构,备忘录模式(Memento),参与者 Originator：原发器 Memento：备忘录 Caretaker：负责人,备忘录模式(Memento),public class Originator

11、private string _state; public string State get return _state; set _state = value; / 创建备忘录，将当前要保存的信息导入并实例化备忘录 public Memento CreateMemento() return (new Memento(this.State); / 恢复备忘录，将Memento导入并将相关数据恢复 public void SetMemento(Memento memento) this.State = memento.State; / 展示状态数据 public void Show() Cons

12、ole.WriteLine(当前状态是: + this.State); ,备忘录模式(Memento),public class Memento private string _state; public string State get return _state; set _state = value; public Memento(string state) this.State = state; ,备忘录模式(Memento),public class Caretaker private Memento _memento; public Memento Memento get retu

13、rn _memento; set _memento = value; ,备忘录模式(Memento),static void Main(string args) Originator o = new Originator(); /初始状态为On o.State = On; o.Show(); /创建备忘录并保存状态 Caretaker caretaker = new Caretaker(); caretaker.Memento = o.CreateMemento(); /更改Originator状态=Off o.State = Off; o.Show(); /恢复到原始状态 o.SetMeme

14、nto(caretaker.Memento); o.Show(); Console.ReadKey(); ,备忘录模式(Memento),电脑销售代理备忘录,备忘录模式(Memento),备忘录模式(Memento),class SalesProspect private string _name; private string _phone; private double _budget; public string Name get return _name; set _name = value; Console.WriteLine(Name: + _name); public strin

15、g Phone get return _phone; set _phone = value; Console.WriteLine(Phone: + _phone); public double Budget get return _budget; set _budget = value; Console.WriteLine(Budget: + _budget); public Memento SaveMemento() Console.WriteLine(nSaving state -n); return new Memento(_name, _phone, _budget); public

16、void RestoreMemento(Memento memento) Console.WriteLine(nRestoring state -n); this.Name = memento.Name; this.Phone = memento.Phone; this.Budget = memento.Budget; ,备忘录模式(Memento),class Memento private string _name; private string _phone; private double _budget; public Memento(string name, string phone

17、, double budget) this._name = name; this._phone = phone; this._budget = budget; public string Name get return _name; set _name = value; public string Phone get return _phone; set _phone = value; public double Budget get return _budget; set _budget = value; ,备忘录模式(Memento),class ProspectMemory privat

18、e Memento _memento; / Property public Memento Memento set _memento = value; get return _memento; ,备忘录模式(Memento),static void Main(string args) SalesProspect s = new SalesProspect(); s.Name = 张三; s.Phone = (027) 82560990; s.Budget = 25000.0; / Store internal state ProspectMemory m = new ProspectMemory(); m.Memento = s.SaveMemento(); s.Name = 李四; s.Phone = (027) 82097111; s.Budget = 10