Thanks Alex and David, those are good arguments. So option 2 it is. Stephen
On 26 October 2017 at 23:05, David Lloyd <david.ll...@redhat.com> wrote: > On Thu, Oct 26, 2017 at 3:03 PM, Stephen Colebourne > <scolebou...@joda.org> wrote: >> For most service providers, option 2 is obvious, however for logging >> it is generally the case that only one implementation should be >> present. If all the jar files that implement a specific logging API >> had the same module name (option 1) then the module system could >> ensure that only one was loaded. This is a particular concern as it is >> not uncommon for a jar file in Maven Central to depend on a specific >> implementation of logging when it should only be depending on the API. > > This is actually a general special case (if you follow my meaning): > that of an API which uses services to locate an implementation, yet > typically only one implementation should be existent and used. For > example, I/O or other platform-dependent systems also spring to mind: > they have a common API, but you generally only want one implementation > (except maybe in some special cases - just like for logging). > > I think that in any case, be it a singleton-ish provider case like one > of the above or a multiple-provider case, it is always appropriate to > choose a unique module name for implementations. It's not appropriate > for an API to prescribe an implementation module name. > > Perhaps we can enhance Jigsaw in the future with some kind of feature > that enforces singleton implementations, if it becomes any sort of > practical problem. > > -- > - DML
