java - 继承集合

Question

我有这门课

public class Room{

private int n_bed;
private float cost;

private Collection<Client> clientlist;

public Room(int n,float c){

    n_bed = n;
    cost = c;

    clientlist = new ArrayList<Client>();
}

}

这个类继承自上面的类

public class RoomWithBar extends Room{

private Collection<Drink> drinkslist;

public RoomWithBar(int n,float cost){

    super(n,cost);

    drinkslist = new ArrayList<Drink>();
}

public Collection<Drink> getDrinksList(){

    return drinkslist;
}

public void addDrink(Drink drink){

    drinkslist.add(drink)
}

}

我的问题是:我还必须在 RoomWithBar 类中插入集合 clientlist，否则集合会自动继承？

Answer 1

这就是 protected 修饰符的作用。

protected Collection<Client> clientlist;

现在，clientlist 将可以在派生类中访问。

详情click here.