javawriter VS JavaParser

javapoet (for generating code in Java): square/javapoet: A Java API for generating .java source files. (github.com)

Resources: 1. Spring Boot Official Documentation on configuring multiple data sources: Spring Boot Reference Documentation 2. javapoet (for generating code in Java): square/javapoet: A Java API for generating .java source files. (github.com) 3. Guide to Annotation Processing in Java: Java Annotation Processing and Creating a Builder | Baeldung

Javapoet. This helped me a lot, because i wrote two generators, one for one employer, who don't like dynamic generators, so the first was to generate mappers like mapstruct does; from model to pojos and viceversa. The second one was a static testing pojo factory generator; this last one i made public (it's pretty basic and now we have projects like instancio and podam) its name is mother-factory.

> can you show an example of how you'd parse, say, a .java.in

The canonical way to do such a thing is through the java annotation processing api [1] and using a tool like java poet [2]. Before you did that, you'd probably decide if you wanted to instead use bytecode generation with a library like bytebuddy [3]

But, assuming for some reason, you wanted to torture yourself and actually consume a java.in file and apply a regex, then you'd probably pull out the "maven-replacer-plugin" [4] and configure that for the task at hand. (or use your favorite templating language plugin. There's a million of them).

Though, to be fair, this really isn't something that comes up in regular java programming due to the nature of the ecosystem. Anything you'd want to codegen likely already has a library and anything you didn't would receive (legitimate) push back.

[1] https://www.baeldung.com/java-annotation-processing-builder

[2] https://github.com/square/javapoet

[3] https://bytebuddy.net/

[4] https://github.com/beiliubei/maven-replacer-plugin

I’ve used a maven archetype before with velocitemplate. That solution was iffy so we then migrated to using https://github.com/square/javapoet to generate the java source and write it to the desired files. I think we also used the google formatter library so the files would be formatted after generating.

JavaPoet

As I have never seen generic constructors before I wanted to know how "real-world" code uses them. So I wrote a program that parses the Java files in the JDK source code. It uses the JavaParser open-source library. Since its README file mentions Java 15, I ran the program on tag jdk-15+36 of the JDK source code.

GitHub released a pretty good java parser that I think is is related to this work https://github.com/javaparser/javaparser

I'm also using that parser using for a side project where developers can cross link their source code and host them statically: https://github.com/josephmate/OdinCodeBrowser#readme

JavaParser

So after taking a deeper look into the docs I've seen that analysis is done via https://github.com/javaparser/javaparser/ lib which has currently only support up to JDK14 (not JDK15, JDK16 nor JDK17...maybe JDK18)...Unfortunately I have not found a full working example for a Java build ...can you give a link?

Depending on the type of refactorings needed, you may be able to use something like Java parser to read the code, refractor it, and write it out again.