Java界面设计

Question

我最初有一个界面如下.

public interface testMe {
      public Set<String> doSomething();
}
public class A implements testMe {
      public Set<String> doSomething() {
           return // Set<String>
      }
}

我有类似的类实现testMe.现在我必须再添加一个返回的类Set<Some Object>

public class X implements testMe() {
     public Set<Some OBject> doSomething() {
     }
}

如何在不破坏现有类的情况下在界面中添加此方法？

Answer 1

您可以使用

public interface testMe {
   public Set<?> doSomething();
}

要么

public interface testMe {
   public Set<? extends CommonSuperclass> doSomething();
}