RFR 8149757:Implement Multi-Release jar aware JavacFileManager for javac

[Steve Drach]

Let me see what I can do with Target.  It would be nicer.

> On Apr 6, 2016, at 1:14 PM, Jonathan Gibbons <jonathan.gibbons at oracle.com> wrote:
> 
> Steve,
> 
> At this point, I would be prepared to accept the review, unless you want to tweak the string bashing and add/use a method on Target.
> 
> -- Jon
> 
> On 04/06/2016 12:13 PM, Steve Drach wrote:
>> Hi,
>> 
>> Thanks for the comments.  For the moment, “stay tuned”, I’ll have to figure out how to do some of this.  I’m not very familiar with the code.
>> 
>>> On Apr 6, 2016, at 11:40 AM, Jan Lahoda <jan.lahoda at oracle.com> wrote:
>>> 
>>> -where there consideration on how this will work with other file managers? (Esp. given the instanceof in Main?) The other file manager may be a relatively simple wrapper over the JavacFileManager (an example would be:
>>> http://hg.openjdk.java.net/jdk9/dev/langtools/file/329ae120e365/src/jdk.jshell/share/classes/jdk/jshell/MemoryFileManager.java
>>> )
>>> 
>>> Seems to me that maybe using isSupportedOption("multi-release") instead of the instanceof would provide a more seemless integration.
>>> 
>>> -why is JavacFileManager.getJarFSProvider() needed? Shouldn't
>>> FileSystems.newFileSystem(realPath, env);
>>> be enough? (Calling an SPI directly from an API client seems suspicious to me.)
>>> 
>>> -for Jon's comment on converting Target to a number, JDKPlatformProvider uses:
>>> Integer.toString(target.ordinal() - Target.JDK1_1.ordinal() + 1)
>>> 
>>> But a method on Target providing the number would be better, of course.
>>> 
>>> Jan
>>> 
>>> On 5.4.2016 23:02, Steve Drach wrote:
>>>> Hi,
>>>> 
>>>> Please review the changes required to make javac and the
>>>> StandardJavaFileManager multi-release jar aware.  For javac, the version
>>>> of the classes in a multi-release.jar is selected by the -release (or
>>>> -target) command line option, or if the option is not present, javac’s
>>>> default policy is used to select the version — typically the runtime
>>>> version (i.e. version 9 is selected for JDK 9).  For the
>>>> StandardJavaFileManager, the version is selected with the handleOption
>>>> method.  See the tests for more detail.
>>>> 
>>>> issue: https://bugs.openjdk.java.net/browse/JDK-8149757
>>>> webrev: http://cr.openjdk.java.net/~sdrach/8149757/webrev/index.html
>>>> 
>>>> Thank you,
>>>> Steve
>