问题描述
我有一个接口和2个实现此接口的类。请参阅下面的代码作为示例。
I have an interface and 2 classes that implement this interface. See the code below as example.
addAchievedMilestone是一个需要在每个类中实现的方法，但只能由同一个包中的类执行。
addAchievedMilestone is a method that needs to be implemented in every class, but can only be executed by a class in the same package.
为什么方法addAchievedMilestone不能受到保护？
Why can't the method addAchievedMilestone be protected?
我希望它受到保护，因此只能使用它按同一个包中的类。
（该方法不会被任何其他类扩展）
I want it to be protected so it can only be used by classes in the same package.(The method won't be extended by any other class)
但是Project-class中的修饰符总是需要公开，我该如何解决这个？
But the modifier in the Project-class always needs to be public, how can I solve this?
示例代码：
package Base;
public interface MilestoneAchievable {
public Milestone getMaxMilestone();
void addAchievedMilestone(Milestone m) throws Exception;
}
项目类：
package Base;
public class Project implements MilestoneAchievable{
public Milestone getMaxMilestone() {
//implementation goes here
}
public void addAchievedMilestone(Milestone m) throws Exception
{
//implementation goes here
}
}
推荐答案
接口中声明的任何方法都是公共的。
子类不能降低方法的可见性/访问权限。
请参阅
了解详情。
Any method declared in an interface is public.And sub classes cannot reduce visibility/access of a method.See Why can't you reduce the visibility of a method in a Java subclass?for details.
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