RFR: JDK-8227046: compiler implementation for sealed classes, JDK-8227047: Javadoc for sealed types and JDK-8227044: javax.lang.model for sealed classes

[Maurizio Cimadamore]

On 21/05/2020 06:31, Joe Darcy wrote:
> Hi Jan,
>
> On 5/19/2020 5:44 AM, Jan Lahoda wrote:
>> Hi Vicente,
>>
>> javac changes look overall OK to me.
>>
>>
> [snip]
>
>
>> -regarding TypeElement#getPermittedSubclasses: it currently returns 
>> List<? extends TypeMirror>; I wonder if returning List<? extends 
>> TypeElement> would be better?
>>
> I did discuss this design point with Vicente ahead of time. While we 
> could probably get away with List<TypeElement> here with the current 
> design, I think List<TypeMirror> is more in keeping with 
> TypeElement.getSuperclass returning a TypeMirror.

What do you think, in general of the 'getPermittedSubclasses' name? This 
term doesn't seem to apply to interfaces, as per section 8.1.4:

" The optional extends clause in a normal class declaration specifies 
the direct superclass of the current class. "

...

"A class is said to be a direct subclass of its direct superclass. The 
direct superclass is the class from whose implementation the 
implementation of the current class is derived. "

"The subclass relationship is the transitive closure of the direct 
subclass relationship. A class A is a subclass of class C if either of 
the following is true:

     A is the direct subclass of C

     There exists a class B such that A is a subclass of B, and B is a 
subclass of C, applying this definition recursively.

"

So, if I have:

sealed interface A permits I1, I2 { ... }
sealed interface I1 { ... }
sealed interface I2 { ... }

Having a method called 'getPermittedSubclasses' give me the mirrors for 
I1 and I2 seems odd.

Maurizio

>
> Thanks,
>
> -Joe
>