如何不允许对所有类使用我自己的注释，而不是对实现具体接口的类进行使用

Question

I have the following code. I need to allow usage of this annotation (CommandName) ONLY for classes-instances of ICommand interface. How can I do it?

    @Retention(RetentionPolicy.RUNTIME) // Make this annotation accessible at runtime via reflection.
@Target({ElementType.TYPE})       // This annotation can only be applied to class methods.

public @interface CommandName {
    String value();
}

Answer 1

In compile time, you cant do that. In runtime, just check the classes - which is annotated by CommandName annotation - if they are implementing the ICommand interface.