[kotlin-server][jax-rs] Added support for JAX-RS library into Kotlin Server generator

[anttileppa]

Added support for JAX-RS library into Kotlin Server generator. New generator can be tested using kotlin-server generator with jaxrs-spec library.

Ping @jimschubert

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh
  

  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  For Windows users, please run the script in Git BASH.
• File the PR against the correct branch: master (5.3.0), 6.0.x
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

[wing328]

cc @jimschubert (2017/09) ❤️, @dr4ke616 (2018/08) @karismann (2019/03) @Zomzog (2019/04) @andrewemery (2019/10) @4brunu (2019/11) @yutaka0m (2020/03)

[wing328]

BUILD SUCCESSFUL in 1m 57s
6 actionable tasks: 6 executed

Tested locally and the result is good. Thanks for the PR.

[regispl]

Hey,

First of all, big thanks @anttileppa and @wing328 , this PR came very handy for me this week, I appreciate your work on it 👏

Secondly, I realise that this PR is closed and merged, but I thought I'd ask here before I report the issue, because perhaps it's my understanding that's the issue here, not the code :-)

I'm trying to generate the code for the API that's hosted under api. For this reason I defined:

servers:
  - url: /api  

in my definition and based on my experience with other generators I'd expect it to work as a "prefix" for all REST resources. Unfortunately what's generated by the jaxrs-spec library is:

@Path("/")

(not surprising given what's in this line of the template 😉 )
meaning that the e.g. resource xyz would exist under /xyz rather than /api/xyz.

Conversely, a Kotlin client generated from the same spec prefixes all the URLs with /api - such a "mismatch" between the generated client and the server code logic makes me think that perhaps something is not right.

My question is: was "/" intentionally hardcoded here or is this perhaps a mistake? Alternatively, if that top-level "prefix" is not desired for some reason - should it perhaps be used as a prefix for each API method @Path?

(disclaimer: it's my first contact with JAX-RS, which could be where the problem is 😉 )

[anttileppa]

@regispl sounds like a mistake to me