/**
 * 备忘录类，保存了一个状态，同时还有保存的日期，根据日期可以来检索保存的备忘
 */
public class Backup {
    private String state;
    private Date date;

    public Backup(String state) {
        this.state = state;
        date = new Date();
    }

    public String getState() {
        return state;
    }

    public void setState(String state) {
        this.state = state;
    }

    public Date getDate() {
        return date;
    }
}

/**
 * 备忘录管理对象，可以读取或者添加备忘录
 */
public class Recovery {
   private List<Backup> backups = new ArrayList<Backup>();

   public void add(Backup backup) {
      backups.add(backup);
   }

   public Backup retrieve(Date date) {
      for (Backup backup : backups) {
         if (backup.getDate().equals(date)) {
            backups.remove(backup);
            return backup;
         }
      }
      return null;
   }
}

/**
 * 需要备忘的对象
 */
public class Application {
   private String state = "default setting";

   public Backup backup() {
      return new Backup(state);
   }

   public void recover(Backup backup) {
      this.state = backup.getState();
   }

   public void setState(String state) {
      this.state = state;
   }

   public String getState() {
      return state;
   }
}

public class Main {

    public static void main(String[] args) {
        Application application = new Application();
        Recovery recovery = new Recovery();

        System.out.println(application.getState());

        Backup backup = application.backup();  // 建立备忘
        recovery.add(backup); // 加入备忘录

        application.setState("customer setting");
        System.out.println(application.getState());

        Date date = backup.getDate(); // 假设 date 是使用者自行设定所要取得的还原时间！
        application.recover(recovery.retrieve(date)); // 取出备忘录来还原
        System.out.println(application.getState());
    }

}

public abstract class CaffeineBeverage {

    private boolean isNeedToAddCondiments = true;

    /**
     * 通用算法
     * 大体的制作流程
     */
    public final void prepareRecipe() {
        boilWater();
        brew();
        pourInCup();
        if (customerWantsCondiments()) {
            addCondiments();
        }
    }

    /**
     * 不同的部分，由子类实现
     */
    protected abstract void brew();

    /**
     * 不同的部分，由子类实现
     */
    protected abstract void addCondiments();

    private void boilWater() {
        System.out.println("Boiling water");
    }

    private void pourInCup() {
        System.out.println("Pouring into cup");
    }

    /**
     * 询问是否需要额外添加品
     * @return true if needed
     */
    public boolean customerWantsCondiments() {
        return isNeedToAddCondiments;
    }

    /**
     * 设置是否需要额外添加品
     */
    public void setCustomerWantsCondiments(boolean needToAddCondiment) {
        isNeedToAddCondiments = needToAddCondiment;
    }
}

public class Coffee extends CaffeineBeverage {

    @Override
    protected void brew() {
        System.out.println("Dripping Coffee through filter");
    }

    @Override
    protected void addCondiments() {
        System.out.println("Adding Sugar and Milk");
    }
    
}

public class Tea extends CaffeineBeverage {

    @Override
    protected void brew() {
        System.out.println("Steeping the tea");
    }

    @Override
    protected void addCondiments() {
        System.out.println("Adding Lemon");
    }

}

public class TeaHouseClient {
   public static void main(String[] args) {
 
      Tea tea = new Tea();
      Coffee coffee = new Coffee();
 
      System.out.println("\nMaking tea...");
      tea.prepareRecipe();
 
      System.out.println("\nMaking coffee...");
      coffee.setCustomerWantsCondiments(false);
      coffee.prepareRecipe();

   }
}