构造一个通用的Java类，其中T是foo类或foo的子类

Question

I have a class Foo with subclass SubFoo , a collection class FooListing .

I want to create a generic FooListing<T> where T is either Foo or a subclass of Foo

From the wording of the documentation (under 'Wildcards'), it sounds like

public class FooListing<T extends Foo> { ... }

...would let me use FooListing<SubFoo> , but not FooListing<Foo> , is this correct?

Answer 1

No, you're already fine - what you've got allows T to be Foo .

I've tried to find the relevant bit of the spec, but unfortunately it's extremely opaque :( It definitely works though!