[External] : Re: provides and requires static ... runtime error

[Ron Pressler]

On 24 Apr 2023, at 14:23, Josiah Noel <josiahnoel at gmail.com<mailto:josiahnoel at gmail.com>> wrote:


I’m confused. To use the implementation of the `x.Plugin` service (defined in X) that you want Y to `provides` an implementation of, some module *must* have a `uses x.Plugin`. The runtime has to know that that service is needed by the program. Maybe the application `uses` it, but X itself could also declare that it `uses` an implementation of a service interface that it, itself, declares. So perhaps it is X that `uses X.plugin`, but someone has to actually say they want to use the service.

I believe I'm picking up what you're putting down, but let's review it again to be sure.


In artifact X we have:


    exports x.spi;
    uses x.spi.Plugin;

in artifact Y we have two modules: y and y.inject.

    exports y.stuff;

And
    requires x;
    provides x.spi.Plugin with y.inject.PluginImpl;

With this in mind, we have two situations we want to support. we have an application Z that wants to use the Y artifact alone and a case where Z wants to use X and Y.

With Y alone, the z module should look like this correct?

    requires y;

 And in the case where Z wants both X and Y (with X doing the service-loading), we do:

    requires x;
    requires y;

Am I right to understand that X will service load the y.inject plugin correctly?

Yes.
This is also how it works today, only y and y.inject must be in two separate JARs.

— Ron
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.openjdk.org/pipermail/jigsaw-dev/attachments/20230424/8fe6030a/attachment.htm>