On 21 April 2017 at 13:00, Stephen Colebourne <scolebou...@joda.org> wrote: > Hi All, > Java 9 is coming soon (unless it is delayed again, but that seems > unlikely). The major feature is JPMS, the Java Platform Module System. > While JPMS is far from ideal, projects like Apache Commons and mine > Joda-* are going to be key to getting some adoption. This is > particularly true as Commons projects tend to be at the base of the > dependency tree. > > I've written up my recommendations for naming modules here: > http://blog.joda.org/2017/04/java-se-9-jpms-module-naming.html > Basically, it strongly recommends reverse-DNS naming based on the > super-package of a project. > > What is needed now? > > Apache Commons, and Apache in general, needs to agree to use a > consistent naming strategy for modules. As per my writeup, I strongly > recommend using the super-package name as the module name, as most > Apache projects already have good separation by package name. > > It will be important to ensure complete separation however, as JPMS > does not allow the same package to be in two modules. > > Finally, it is important to note that modules are not the same as > artifacts. Modules, and thus their names, represent the JVMs view of > the structure of an application. Artifacts are a transport mechanism > (jar file), and many different artifacts can provide the same module. > This becomes apparent when considering the Apache branded JSR jar > files, for example the module name might be javax.servlet (ie. not > referencing Apache), but the artifactId is apache-jsr-360 (which does > reference Apache). > > > So, how to apply this to Commons (and Apache in general)? > > Well, I haven't examined each commons subproject, but from my time > contributing years ago, each subproject has its own package name. > Thus: > > Commons-IO > -> super-package org.apache.commons.io > -> module org.apache.commons.io > > Commons-Lang3 > -> super-package org.apache.commons.lang3 > -> module org.apache.commons.lang3 > > > If everyone agrees, the module name for each project should be > documented somewhere on the website. Note that this should be done > _now_, but does not require creating a module-info.java file, or > otherwise preparing for Java 9. > > Comments? Questions?
What happens when there is a API break which necessitates a package name change? I assume that the module name will also need to change to the new super-package. e.g. Commons-Lang4 -> super-package org.apache.commons.lang4 -> module org.apache.commons.lang4 AFAICT Commons generally has obvious and unique super-packages for each component. This should make it easier than for larger projects with lots of jars and potentially overlapping package names. However even Commons has some code that uses a different package structure. e.g. NET uses examples as the super-package. This includes working examples that are included in the release. I guess that will have to change (which is probably a good idea anyway). > thanks > Stephen > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > For additional commands, e-mail: dev-h...@commons.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
