Scanning multi version jars?

[Greg Wilkins]

Alen et al,

here is a VersionedJarFile implementation that filters out inappropriate
inner classes:

https://gist.github.com/gregw/8f305e369d0b769e9c3fe791a0634b13

cheers

On 16 September 2017 at 07:58, Greg Wilkins <gregw at webtide.com> wrote:

>
> Alan,
>
> I had a quick look at `jdk.internal.util.jar.VersionedStream` and have
> the following comments:
>
>    - The style of the API is fine - pass in a JarFile and get a
>    Stream<JarEntry>.
>    - It might be better to have a Stream<VersionedJarEntry> which
>    includes a method to query the actual version of each entry.
>    - I think the stream needs to handle inner classes and only include
>    them if their matching outerclass is available at the same version.  So for
>    example a base Foo$Bar.class will only be included if the stream includes a
>    base Foo.class, and it will not be included if the Foo.class is version 9
>    or above.  Likewise a version 9 Foo$Bar.class will only be included in the
>    stream if the stream also includes a version 9 Foo.class, and will not  be
>    included if the stream has a version 10 or above Foo.class
>
> If you think this last point is possible, then I'll move the discussion
> back the EE expert groups to try to get an agreement on the exact stream
> code that will be used in the mid term until it is available in the JRE
> lib, at which time the specs should be amended to say they will defer the
> decision of which classes to scan the JRE lib so they will be future proof
> for any changes in java 10, 11 etc.
>
> cheers
>
>
>
>
> On 15 September 2017 at 17:27, Alan Bateman <Alan.Bateman at oracle.com>
> wrote:
>
>>
>>
>> On 15/09/2017 03:09, Greg Wilkins wrote:
>>
>>>
>>> Alan,
>>>
>>> thanks for correcting me on the API of JarFile - I can see it kind of
>>> works, but in a very bizarre way (it gives different content for entries
>>> obtained via the enumerator vs the getJarEntry API, even though both
>>> entries report the same name).  But I'll discuss that elsewhere.
>>>
>> This is something that was discussed on core-libs-dev on a number of
>> occasions. The summary is that JarFile needs a new API for this,
>> versionedStream() was suggested, but it was kicked down the road for later
>> in order deal with the fallout from adding MR JARs.
>>
>> Since you have access to the code then look at
>> jdk.internal.util.jar.VersionedStream for an example code of what I
>> think you are looking for.
>>
>> -Alan
>>
>
>
>
> --
> Greg Wilkins <gregw at webtide.com> CTO http://webtide.com
>



-- 
Greg Wilkins <gregw at webtide.com> CTO http://webtide.com