Question

我的接口（A）中有一个接受另一个接口（B）作为参数的方法。当我去实现（A）并传递一个实现接口（B）的对象（C）时，我被保持向下传播（B）到传递对象的正确实现（C）。

例如......

public interface A {
    public void theMethod(B theObject);
}

public interface B {
    public Properties jarJar();

    public boolean isActuallyAJedi();

    public void srsly();
}

public class C implements B {
    //mumbo dumbo stuff from B
}

public class D implements A {
    public void theMethod(B theObject) { // <------ I would prefer to explicitly define C as it is implementing B
        C theUpcastedObject = (C) theObject; // <------ I want to avoid downcast here

        theUpcastedObject.isActuallyAJedi();

        theObject.srsly(); // <----- won't work because it is not aware of the implementation...
    }
}

public class Main {
    public static void main(String[] args) {
        D stuffIWillDo = new D();
        B theObject = new C(); // explicitly showing the implementation here...

        D.theMethod(theObject);

    }
}

我希望这能很好地解释这一点！

Answer 1

实现接口C的类B不会覆盖接口B的方法。我想你在这里尝试做的是扩展接口B。但是一个类不能扩展接口。你可以在这里做的是使C接口扩展接口B。

Java接口的方法使用另一种接口类型

1 个答案: