On Wed, 25 May 2022 00:35:24 GMT, Joe Darcy <da...@openjdk.org> wrote:
>> This is an early review of changes to better model JVM access flags, that is >> "modifiers" like public, protected, etc. but explicitly at a VM level. >> >> Language level modifiers and JVM level access flags are closely related, but >> distinct. There are concepts that overlap in the two domains (public, >> private, etc.), others that only have a language-level modifier (sealed), >> and still others that only have an access flag (synthetic). >> >> The existing java.lang.reflect.Modifier class is inadequate to model these >> subtleties. For example, the bit positions used by access flags on different >> kinds of elements overlap (such as "volatile" for fields and "bridge" for >> methods. Just having a raw integer does not provide sufficient context to >> decode the corresponding language-level string. Methods like >> Modifier.methodModifiers() were introduced to cope with this situation. >> >> With additional modifiers and flags on the horizon with projects like >> Valhalla, addressing the existent modeling deficiency now ahead of time is >> reasonable before further strain is introduced. >> >> This PR in its current form is meant to give the overall shape of the API. >> It is missing implementations to map from, say, method modifiers to access >> flags, taking into account overlaps in bit positions. >> >> The CSR https://bugs.openjdk.java.net/browse/JDK-8281660 will be filled in >> once the API is further along. > > Joe Darcy has updated the pull request with a new target base due to a merge > or a rebase. The incremental webrev excludes the unrelated changes brought in > by the merge/rebase. The pull request contains 32 additional commits since > the last revision: > > - Target JDK 20 rather than 19. > - Merge branch 'master' into JDK-8266670 > - Add mask values to constants' javadoc. > - Implement review feedback from mlchung. > - Fix type in @throws tag. > - Merge branch 'master' into JDK-8266670 > - Respond to review feedback. > - Merge branch 'master' into JDK-8266670 > - Make workding changes suggested in review feedback. > - Merge branch 'master' into JDK-8266670 > - ... and 22 more: > https://git.openjdk.java.net/jdk/compare/43363358...05cf2d8b With the `AccessFlag` API, what is the role of the `Modifier` API going forward? [Value Objects JEP](https://openjdk.java.net/jeps/8277163) defines the new `identity` and `value` modifiers. [PR #698](https://github.com/openjdk/valhalla/pull/698) proposes to add `Modifier.IDENTITY` and `Modifier.VALUE` constants as the `identity` and `value` modifiers are encoded in a class file using the `ACC_IDENTITY` and `ACC_VALUE` flags. However, with the new improved `AccessFlag` API, the new flags will be defined in the `AccessFlag` API. I think we should avoid adding the new flags in `Modifier` and leave it for the existing usage. Use `AccessFlag` for new features. ------------- PR: https://git.openjdk.java.net/jdk/pull/7445
