[incubator-kie-issues#1395] Write developer documentation for the DMN implementation

[gitgabrio]

Fixes apache/incubator-kie-issues#1395

@bncriju

How to replicate CI configuration locally?

Build Chain tool does "simple" maven build(s), the builds are just Maven commands, but because the repositories relates and depends on each other and any change in API or class method could affect several of those repositories there is a need to use build-chain tool to handle cross repository builds and be sure that we always use latest version of the code for each repository.

build-chain tool is a build tool which can be used on command line locally or in Github Actions workflow(s), in case you need to change multiple repositories and send multiple dependent pull requests related with a change you can easily reproduce the same build by executing it on Github hosted environment or locally in your development environment. See local execution details to get more information about it.

How to retest this PR or trigger a specific build:

• for pull request and downstream checks

  • Push a new commit to the PR. An empty commit would be enough.

• for a full downstream build

  • for github actions job: add the label run_fdb

• for Jenkins PR check only

  • If you are an ASF committer for KIE podling, login to Jenkins (https://ci-builds.apache.org/job/KIE/job/drools/), go to the specific PR job, and click on Build Now button.

[tiagobento]

Hi @gitgabrio, I have some questions about the .puml files you added... I see they're also present for documenting other parts of the project, but I'm not familiar with them. Do you mind providing details about how to edit, visualize, re-generate the PNGs based on them? I'm asking because these diagrams can change in the future, based on changes applied to the code, so having instructions on how to manage them is essential for keeping these docs up-to-date. Thanks in advance! And sorry if this is already written somewhere I didn't find.

[bncriju]

This documentation is readable and understandable even to a new person who might not have complete knowledge of the same. It was nice if the sections 'Interpreted vs Codegen' and 'Coercion' were little more explanatory. Thanks

[bncriju]

Changes made look good and now the sections mentioned are easy to be understood. Also the main Readme looks good. Thanks

[gitgabrio]

Hi @gitgabrio, I have some questions about the .puml files you added... I see they're also present for documenting other parts of the project, but I'm not familiar with them. Do you mind providing details about how to edit, visualize, re-generate the PNGs based on them? I'm asking because these diagrams can change in the future, based on changes applied to the code, so having instructions on how to manage them is essential for keeping these docs up-to-date. Thanks in advance! And sorry if this is already written somewhere I didn't find.

Since it involves different modules, I add it to top-level "Readme"