【GOF23设计模式】备忘录模式

 1 package com.test.memento;
 2 /**
 3  * 源发器类
 4  */
 5 public class Emp {
 6     private String ename;
 7     private int age;
 8     private double salary;
 9 
10     //进行备忘操作，并返回备忘录对象
11     public EmpMemento memento(){
12         return new EmpMemento(this);
13     }
14 
15     //进行数据恢复，恢复成制定备忘录对象的值
16     public void recovery(EmpMemento mmt){
17         this.ename = mmt.getEname();
18         this.age = mmt.getAge();
19         this.salary = mmt.getSalary();
20     }
21     public Emp(String ename, int age, double salary) {
22         super();
23         this.ename = ename;
24         this.age = age;
25         this.salary = salary;
26     }
27     public String getEname() {
28         return ename;
29     }
30     public void setEname(String ename) {
31         this.ename = ename;
32     }
33     public int getAge() {
34         return age;
35     }
36     public void setAge(int age) {
37         this.age = age;
38     }
39     public double getSalary() {
40         return salary;
41     }
42     public void setSalary(double salary) {
43         this.salary = salary;
44     }
45 }

 1 package com.test.memento;
 2 /**
 3  * 备忘录类
 4  */
 5 public class EmpMemento {
 6     private String ename;
 7     private int age;
 8     private double salary;
 9 
10     public EmpMemento(Emp e){
11         this.ename = e.getEname();
12         this.age = e.getAge();
13         this.salary = e.getSalary();
14     }
15 
16     public String getEname() {
17         return ename;
18     }
19     public void setEname(String ename) {
20         this.ename = ename;
21     }
22     public int getAge() {
23         return age;
24     }
25     public void setAge(int age) {
26         this.age = age;
27     }
28     public double getSalary() {
29         return salary;
30     }
31     public void setSalary(double salary) {
32         this.salary = salary;
33     }
34 }

 1 package com.test.memento;
 2 
 3 import java.util.ArrayList;
 4 
 5 /**
 6  * 负责人类
 7  */
 8 public class CareTaker {
 9     private EmpMemento memento;
10 
11 //  private List<EmpMemento> list = new ArrayList<EmpMemento>();
12 
13     public EmpMemento getMemento() {
14         return memento;
15     }
16 
17     public void setMemento(EmpMemento memento) {
18         this.memento = memento;
19     }
20 }

 1 package com.test.memento;
 2 
 3 public class Client {
 4     public static void main(String[] args) {
 5         CareTaker careTaker = new CareTaker();
 6 
 7         Emp emp = new Emp("小高", 18, 900);
 8         System.out.println("第一次打印对象："+emp.getEname()+"--"
 9                 +emp.getAge()+"--"+emp.getSalary());
10 
11         careTaker.setMemento(emp.memento());//备忘一次
12 
13         emp.setAge(38);
14         emp.setEname("小搞");
15         emp.setSalary(9000);
16 
17         System.out.println("第二次打印对象："+emp.getEname()+"--"
18                 +emp.getAge()+"--"+emp.getSalary());
19 
20         emp.recovery(careTaker.getMemento());//恢复到备忘录对象保存的状态
21 
22         System.out.println("第三次打印对象："+emp.getEname()+"--"
23                 +emp.getAge()+"--"+emp.getSalary());
24     }
25 }

控制台输出：
第一次打印对象：小高--18--900.0
第二次打印对象：小搞--38--9000.0
第三次打印对象：小高--18--900.0