I too +1
My experience porting a Java project to Kotlin was specific to Android in
the past (re: years ago). I recall my general impression of Kotlin to have
some extraneous and unnecessary syntactic sugar (What's up with the
for/loop keywords?), but it was an overall solid language. I appreciate the
terseness and brevity of things like variable declarations w/ implicit data
types and `data classes`, which addresses a long standing complaint about
Java's overly verbose syntax. Language aside, the automated porting back
then wasn't exactly perfect, but a few things have changed since then; 1)
the language specification has solidified over the years, 2) tooling has
matured, and 3) is manageable to manually intervene if necessary.
> As a side note, because of Oracle's aggressive legal practices, and
because
they really do want you to think that they own Java (see: Google LLC v.
Oracle America, Inc.), using Java in Apache Traffic Control is not
really
in the spirit of free software. Kotlin is an Apache 2.0-licensed
project,
so switching to Kotlin would be a true FOSS win for the ATC community.
I think the true benefit is moving away from the Java API, which is under
such contention, without changing underlying implementation (such as a
transition to another, non-JVM, language might incur).
On Tue, Jun 22, 2021 at 11:42 AM Chatterjee, Srijeet
<[email protected]> wrote:
> +1
> Sounds like a fun project!
>
> --Srijeet
>
> On 6/21/21, 8:43 PM, "Zach Hoffman" <[email protected]> wrote:
>
> Hi Traffic Control!
>
> As you all may know, the current implementation of Traffic Router runs
> on
> Java 8. While coding directly in Java is still done, there are some
> reasons
> to be critical of Java.
>
> Java often has very verbose syntax when trying to accomplish simple
> things.
> This has made the Traffic Router codebase grow larger over time,
> leading to
> maintainability issues. Also, Java suffers from lack of compile-time
> safety
> in some ways that more modern languages do not. For these reasons, and
> because Java is a very old language, some developers who may otherwise
> be
> interested in contributing to Apache Traffic Control may be
> disinterested
> contributing to Traffic Router in particular, simply because they want
> to
> work with more modern languages that do not have the issues that Java
> does.
>
> Kotlin, a JVM language devised by Jetbrains with the goal of tackling
> these
> problems, has exploded in popularity in recent years, and Kotlin is
> becoming a standard way to use the JVM, with Google choosing it as the
> preferred language to for developing Android apps. More importantly,
> as the
> Intellij IDEA Kotlin plugin lets you convert Java sources to Kotlin
> (either
> at the file level or an entire project, or anywhere in between),
> Kotlin has
> become a low-effort way to decrease tech debt across large Java
> projects.
>
> Back to Traffic Router: In order to gauge how we would benefit from
> converting Traffic Router to Kotlin (it really is a matter of
> *converting*,
> not rewriting), I converted all of the tests in the Traffic Router
> "Core"
> module to Kotlin. You can see the result here (as you can see from
> GitHub
> Actions, the TR tests all pass): <
>
> https://urldefense.com/v3/__https://github.com/zrhoffman/trafficcontrol/commits/tr-kotlin__;!!CQl3mcHX2A!UCz457i9stX5A-AP8jvvWo21Rqa43JRsC1jQt_fo5nb07raZxByUR9gAGVPZTI4tGhalAel2$
> >
>
> Some observations:
> - Without any putting any effort into optimizing the existing code,
> lines
> of code shrunk from 10572 in Java to 10217 in Kotlin. See: <
>
> https://urldefense.com/v3/__https://github.com/zrhoffman/trafficcontrol/commit/5add06bccc__;!!CQl3mcHX2A!UCz457i9stX5A-AP8jvvWo21Rqa43JRsC1jQt_fo5nb07raZxByUR9gAGVPZTI4tGqGQTevX$
> >
> - Because it now includes the Kotlin standard library, the Traffic
> Router
> RPM size increases from 48MB to 58MB.
> - The converted sources benefit from Kotlin's null safety and type
> safety
> (avoiding wildcard types). See <
>
> https://urldefense.com/v3/__https://github.com/zrhoffman/trafficcontrol/commit/0c2eec39d9__;!!CQl3mcHX2A!UCz457i9stX5A-AP8jvvWo21Rqa43JRsC1jQt_fo5nb07raZxByUR9gAGVPZTI4tGjjMNj-F$
> > (Kotlin
> error resolution) and <
>
> https://urldefense.com/v3/__https://github.com/zrhoffman/trafficcontrol/commit/d8a0fd3bca__;!!CQl3mcHX2A!UCz457i9stX5A-AP8jvvWo21Rqa43JRsC1jQt_fo5nb07raZxByUR9gAGVPZTI4tGoysImMb$
> > (Kotlin
> warning resolution) for the changes involved.
>
> As a side note, because of Oracle's aggressive legal practices, and
> because
> they really do want you to think that they own Java (see: Google LLC v.
> Oracle America, Inc.), using Java in Apache Traffic Control is not
> really
> in the spirit of free software. Kotlin is an Apache 2.0-licensed
> project,
> so switching to Kotlin would be a true FOSS win for the ATC community.
>
> So, converting the rest of Traffic Router would be relatively fast and
> easy, would result in *no* functionality gained or lost, would leave TR
> usage totally unchanged, would make development more enjoyable for
> current
> TR devs, and would maybe catch the interest of additional devs who
> otherwise may not be interested in Traffic Router.
>
> How does this sound?
>
> -Zach
>
>
