软件设计20|备忘录模式

一、Java版本

（1）效果如下：

（2）类图如下：

（3）工程目录如下：

（4）代码如下：

Caretaker.java

package memo;

public class Caretaker {
    private Memento memento;

    public void setMemento(Memento memento) {
        this.memento = memento;
    }

    public Memento getMemento() {
        // TODO Auto-generated method stub
        return memento;
    }
    
}

Client.java

package memo;

public class Client {
    public static void main(String[] args) {
        UserInfoDTO user=new UserInfoDTO();
        Caretaker c=new Caretaker();
        Caretaker d=new Caretaker();
        user.setAccount("张三");
        user.setPassword("123456");
        user.setTelNo("123456789");
        System.out.println("状态一：");
        user.show();
        c.setMemento(user.saveMemento());//保存到备忘录中
        System.out.println("************");
        user.setPassword("11111");
        user.setTelNo("321");
        System.out.println("状态二：");
        user.show();
        d.setMemento(user.saveMemento());//保存到备忘录中
        System.out.println("************");
        user.setPassword("22222");
        user.setTelNo("66666");
        System.out.println("状态三：");
        user.show();
        System.out.println("************");
        user.restoreMemento(d.getMemento());//从备忘录中恢复
        System.out.println("回到状态二：");
        user.show();
        System.out.println("************");
        user.restoreMemento(c.getMemento());//从备忘录中恢复
        System.out.println("回到状态一：");
        user.show();
    }
}

Memento.java

package memo;

public class Memento {
    private String account;
    private String password;
    private String telNo;
    
    public Memento(String account,String password,String telNo) {
        this.account=account;
        this.password=password;
        this.telNo=telNo;
    }
    
    public String getAccount() {
        return account;
    }
    public void setAccount(String account) {
        this.account = account;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getTelNo() {
        return telNo;
    }
    public void setTelNo(String telNo) {
        this.telNo = telNo;
    }
    
}

UserInfoDTO.java

package memo;

public class UserInfoDTO {
    private String account;
    private String password;
    private String telNo;

    public Memento saveMemento() {
        return new Memento(account, password, telNo);
    }

    public void restoreMemento(Memento memento){
        this.account=memento.getAccount();
        this.password=memento.getPassword();
        this.telNo=memento.getTelNo();
    }
    
    public void show() {
        System.out.println("Account:"+this.account);
        System.out.println("Password:"+this.password);
        System.out.println("TelNo:"+this.telNo);
    }

    public String getAccount() {
        return account;
    }

    public void setAccount(String account) {
        this.account = account;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getTelNo() {
        return telNo;
    }

    public void setTelNo(String telNo) {
        this.telNo = telNo;
    }
}

（5）参考链接：设计模式十七

二、C++版本

（1）效果如下：

（2）类图如下：

（3）代码如下：

#include<iostream>
using namespace std;

class Memento
{
public:
    string account;
    string password;
    string telNo;
public:
    Memento(){}
    Memento(string account, string password, string telNo) :account(account), password(password), telNo(telNo) {}
    string getAccount() {
        return account;
    }
    void setAccount(string a) {
        account = a;
    }
    string getPassword() {
        return password;
    }
    void setPassword(string p) {
        password = p;
    }
    string getTelNo() {
        return telNo;
    }
    void setTelNo(string t) {
        telNo = t;
    }

};

class UserInfoDTO
{
private:
    string account;
    string password;
    string telNo;
public:
    Memento SaveMemento()
    {
        Memento memento(account, password, telNo);
        return memento;
    }
    void restoreMemento(Memento memento)
    {
        account = memento.account;
        password = memento.password;
        telNo = memento.telNo;
    }
    void Show() {
        cout << "account : " << account << endl;
        cout << "password: " << password << endl;
        cout << "telNo: " << telNo << endl;
    }
    string getAccount() {
        return account;
    }
    void setAccount(string a) {
        account = a;
    }
    string getPassword() {
        return password;
    }
    void setPassword(string p) {
        password = p;
    }
    string getTelNo() {
        return telNo;
    }
    void setTelNo(string t) {
        telNo = t;
    }
};
//保存的进度库
class Caretake
{
public:
    Caretake() {}
    void setMemento(Memento menento) {
        m_memento = menento;
    }
    Memento getMemento() { return m_memento; }
private:
    Memento m_memento;
};

int main()
{
    UserInfoDTO user;
    user.setAccount("张三");
    user.setPassword("11111");
    user.setTelNo("111111");
    cout << "状态一:" << endl;
    user.Show();
    Caretake* c=new Caretake();
    c->setMemento(user.SaveMemento());//保存到备忘录
    cout << "**************" << endl;
    user.setPassword("22222");
    user.setTelNo("222222");
    cout << "状态二:" << endl;
    user.Show();
    Caretake* d = new Caretake();
    d->setMemento(user.SaveMemento());//保存到备忘录
    cout << "**************" << endl;
    user.setPassword("33333");
    user.setTelNo("333333");
    cout << "状态三:" << endl;
    user.Show(); 
    cout << "**************" << endl;
    user.restoreMemento(d->getMemento());//从备忘录中恢复
    cout << "回到状态二:" << endl;
    user.Show();
    cout << "**************" << endl;
    user.restoreMemento(c->getMemento());//从备忘录中恢复
    cout << "回到状态一:" << endl;
    user.Show();
    return 0;
}

（4）参考链接：设计模式C++实现（12）——备忘录模式