exports directive

[Jaroslav Tulach]

Dne Út 19. června 2012 13:17:24, David Holmes napsal(a):
> On 19/06/2012 1:10 PM, Mandy Chung wrote:
> > On 6/18/2012 7:20 PM, David Holmes wrote:
> >> Does export work like a prefix such that
> >> 
> >> exports foo;
> >> 
> >> means the module exports all types in package foo, plus all types in
> >> all subpackages of foo? Or do I need to use multiple exports
> >> directives, or wildcards?
> >> 
> > |exports| takes a qualified identifier indicating a package name. You
> > 
> > need to use multiple |exports| directives to list its subpackages:
> > |module foo {
> > 
> > exports foo;
> > exports foo.spi;
> > exports foo.util;
> > }
> > 
> >> And is this documented somewhere?
> > 
> > http://openjdk.java.net/projects/jigsaw/doc/lang-vm.html
> > http://cr.openjdk.java.net/~mr/jigsaw/notes/jigsaw-big-picture-01
> 
> Thanks Mandy!
> 
> Annoyingly tedious to have to list all the subpackages directly though.
> Libraries that make extensive use of subpackages for grouping things
> will need to use long exports lists. Some kind of wildcard support would
> be quite useful I think.

A tools perspective: Wildcards are pain to support. Example: just by looking 
at module-info.java one cannot deduce list of exported packages. One needs to 
examine all module source files. Tedious.

A user perspective: While wildcards save some time initially, they usually 
bite you back after few years of maintenance. Also they don't work well when 
somebody adds org.myorg.myexportedapi.internal package, which is a common 
pattern used by some open source projects.

-jt