Reusing module name token `*` in -d

Sat Jan 21 13:55:50 UTC 2017

 Hi!

> Ah, i see why you have a problem, a jigsaw module != a sub project
> 
> A sub project with your layout will contain several modules if you 
> prefer. A jigsaw module is more lightweight that the other kind of 
> ''modules'' you usually find in Java and features like restricted 
> export or uses/provides also force several modules to be compiled 
> together.

That's interesting. As far as I understood up to now a single POM (to
fall back on a known build tool) will by default correspond to a
single module. Isn't that so? Or in other words how would I use Maven
or Gradle to effortlessly create multiple artifacts?

 so long ... Nicolai

On 21.01.2017 14:32, forax at univ-mlv.fr wrote:
> ----- Mail original -----
>> De: "Nicolai Parlog" <nipa at codefx.org> À: forax at univ-mlv.fr Cc:
>> jigsaw-dev at openjdk.java.net Envoyé: Samedi 21 Janvier 2017
>> 13:08:24 Objet: Re: Reusing module name token `*` in -d
> 
>> Hi Remi.
> 
> Hi Nicolai,
> 
>> 
>>> My advice is to not try to fight the module layout, it's like 
>>> trying to fight ocean waves, it's better to surf on it.
>> 
>> My personal opinion is that the proposed layout with a src folder
>> at the top is not going to see a lot of adoption.
>> 
>> The main reason for that is that I think each sub-project/module 
>> should have a directory structure just to itself to store
>> sources, tests, resources, configuration, build scripts,
>> documentation, source control info, etc. The fact that most build
>> tool and IDEs understand this structure by default underlines
>> that thought. And not only does the proposed structure not add
>> any benefits (that I can see), it also comes at a considerable
>> costs because (a) all tools have to be taught "the new way" and
>> (b) a migration is a lot of work.
>> 
>> So I believe the
>> `<module>/src/{main,test}/{java,resources,whatever}` structure is
>> here to stay.
> 
> Ah, i see why you have a problem, a jigsaw module != a sub project
> 
> A sub project with your layout will contain several modules if you
> prefer. A jigsaw module is more lightweight that the other kind of
> ''modules'' you usually find in Java and features like restricted
> export or uses/provides also force several modules to be compiled
> together.
> 
>> 
>>> And yes it means that if you want to modularize an already 
>>> existing project, you have to change its layout to be jigsaw 
>>> compatible
>> 
>> I disagree.
>> 
>> I'm not sure how essential it is for tools to have the compiled 
>> classes land in  `<module>/target/classes`. If it is important,
>> they could not have compiled several sub-projects at the same
>> time anyways (unless I'm missing something). If they already put
>> all compiled classes into the same folder, then multi-module
>> builds will work just fine for them.
>> 
>> Not being able to do multi-module builds into 
>> `<module>/target/classes` or similar is hence no new limitation
>> from Java 9 and compiling modules one by one can be done for
>> arbitrary directory structures.
> 
> see my comment above about not being able to compile multiple
> modules in isolation.
> 
> also Java has never supported an arbitrary layout, packages has to
> be organized in a certain way and now that jigsaw modules are part
> of the language. I think the problem is more that what you call a
> module may not be what Java calls a module.
> 
>> 
>> At the same time it looks to me that the concept of a module
>> name token opens up the possibility to create a feature that
>> didn't exist before and allows tools to compile many modules at
>> once where they couldn't before.
>> 
>> so long ... Nicolai
> 
> cheers, Rémi
> 
>> 
>> 
>> 
>> On 21.01.2017 11:37, Remi Forax wrote:
>>> Hi Nicolai, the runtime (ModuleFinder) is able to read
>>> exploded modules, .class in folders, not only modules in jars,
>>> so the layout on disk is more or less fixed.
>>> 
>>> My advice is to not try to fight the module layout, it's like 
>>> trying to fight ocean waves, it's better to surf on it. And yes
>>> it means that if you want to modularize an already existing
>>> project, you have to change its layout to be jigsaw compatible,
>>> this is exactly what was done for the jdk.
>>> 
>>> regards, Rémi
>>> 
>>> ----- Mail original -----
>>>> De: "Nicolai Parlog" <nipa at codefx.org> À: 
>>>> jigsaw-dev at openjdk.java.net Envoyé: Samedi 21 Janvier 2017 
>>>> 11:00:35 Objet: Reusing module name token `*` in -d
>>> 
>>>> Hi!
>>>> 
>>>> Another feature request from the trenches regarding
>>>> multi-module compilation. (It is possible that there was a
>>>> similar thread a couple of days/weeks (?) back but I didn't
>>>> find it.)
>>>> 
>>>> It would be nice to have the ability to specify module
>>>> specific target folders, so they do not automatically end up
>>>> in `<whatever-was-given-to-d>/<module-name>`.
>>>> 
>>>> It seems obvious (which could very well make it stupid) to
>>>> reuse the asterisk here and allow something like
>>>> 
>>>> javac --module-path mods --module-source-path 
>>>> "./*/src/main/java" -d "./*/target/classes" -module 
>>>> initial.module
>>>> 
>>>> I have not thought through how this might or might not work
>>>> with multiple module source paths. It looks like the only
>>>> tractable approach would be to not allow more than one -d
>>>> element.
>>>> 
>>>> so long ... Nicolai
>>>> 
>>>> 
>>>> 
>>>> --
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>>>>
>>>>
>>
>>>> 
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>>> 
>> 
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>>
>> 
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> 

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