RFR: JDK-8275308: Add valueOf(Runtime.Version) factory to SourceVersion [v2]

[Joe Darcy]

On Sat, 16 Oct 2021 00:02:08 GMT, Joe Darcy <darcy at openjdk.org> wrote:

>> I wanted to get input on the design of API of the method before writing the tests.
>> 
>> The new factory method maps from a Runtime.Version object, a object which formally modes the version of the JDK, to a corresponding SourceVersion object.
>> 
>> Given the current histories of versioning of the JDK and SourceVersion this amount to mapping "JDK N" to RELEASE_N, for example, JDK 17 to RELEASE_17, etc. As mentioned in the API note, this could potentially change in the future if the release model changes. Runtime.Version has added in JDK 9, but earlier versions can be modeled. Note that no attempt is made to map "1.2" to RELEASE_2 and that since Runtime.Version grammar does not allow a leading 0 term, RELEASE_0 will *not* be returned by the new method.
>> 
>> Another design point: an out-of-range feature version is treated as an error so a Runtime.Version with a feature of 19 mapped in JDK 18 will fail with an IllegalArgumentException rather than saturating at RELEASE_18. If saturating would be more helpful for the envisioned use cases, I'm open to changing the spec accordingly.
>> 
>> CSR to follow once the API is nailed down.
>
> Joe Darcy has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix typo.

In the latest push, stubbed in support for the reverse mapping from SourceVersion to a runtime version. For now, limiting the mapping to RELEASE_9 and higher since Runtime.Version was added in 9.

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PR: https://git.openjdk.java.net/jdk/pull/5973