Hi Harold,
On 5/27/20 1:35 PM, Harold Seigel wrote:
Incremental webrev:
http://cr.openjdk.java.net/~hseigel/sealedClasses.8225056.incr.2/
full webrev:
http://cr.openjdk.java.net/~hseigel/sealedClasses.8225056.2/webrev/
Class.java
4406 ReflectionData<T> rd = reflectionData();
4407 ClassDesc[] tmp = rd.permittedSubclasses;
4408 if (tmp != null) {
4409 return tmp;
4410 }
4411
4412 if (isArray() || isPrimitive()) {
4413 rd.permittedSubclasses = new ClassDesc[0];
4414 return rd.permittedSubclasses;
4415 }
This causes an array class or primitive type to create a
ReflectionData. It should first check if this is non-sealed class and
returns a constant empty array.
In fact, ReflectionData caches the derived names and reflected members
for performance and also they may be invalidated when the class is
redefined. It might be okay to add ReflectionData::permittedSubclasses
while `PermittedSubclasses` attribute can't be redefined and getting
this attribute is not performance sensitive. For example, the result
of `getNestMembers` is not cached in ReflectionData. It may be better
not to add it in ReflectionData for modifiable and performance-sensitive
data.
4421 tmp = new ClassDesc[subclassNames.length];
4422 int i = 0;
4423 for (String subclassName : subclassNames) {
4424 try {
4425 tmp[i++] = ClassDesc.of(subclassName.replace('/', '.'));
4426 } catch (IllegalArgumentException iae) {
4427 throw new InternalError("Invalid type in permitted subclasses
information: " + subclassName, iae);
4428 }
4429 }
Nit: rename tmp to some other name e.g. descs
I read the JVMS but it isn't clear to me that the VM will validate the
names in `PermittedSubclasses`attribute are valid class descriptors. I
see ConstantPool::is_klass_or_reference check but can't find where it
validates the name is a valid class descriptor - can you point me
there? (otherwise, maybe define it to be unspecified?)
W.r.t. the APIs. I don't want to delay this review. I see that you
renamed the method to new API style as I brought up. OTOH, I expect
more discussion is needed. Below is a recent comment from John on this
topic [1]
One comment, really for the future, regarding the shape of the Java
API here: It uses Optional and omits the "get" prefix on accessors.
This is the New Style, as opposed to the Classic Style using null (for
"empty" results) and a "get" prefix ("getComponentType") to get a
related type. We may choose to to use the New Style for new reflection
API points, and if so let's not choose N different New Styles, but one
New Style. Personally I like removing "get"; I accept Optional instead
of null; and I also suggest that arrays (if any) be replaced by
(immutable) Lists in the New Style
There are a few existing Class APIs that use the new API style:
Class<?> arrayClass();
Optional<ClassDesc> describeConstable();
String descriptorString();
This will set up a precedence of the new API style in this class. Should
this new permittedSubclasses method return a List instead of an array?
It's okay with me if you prefer to revert back to the old API style and
follow this up after integration.
4442 * Returns true if this {@linkplain Class} is sealed.
4443 *
4444 * @return returns true if this class is sealed
NIt: {@code true} instead of true - consistent with the style this
class uses (in most methods)
test/jdk/java/lang/reflect/sealed_classes/SealedClassesReflectionTest.java
Nit: s/sealed_classes/sealedClasses/
- the test directory/file naming convention use camel case or java
variable name convention.
Thanks
[1] https://github.com/openjdk/valhalla/pull/53#issuecomment-633116043
