javawriter VS JavaCPP

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

JavaCPP and presets for working with JNI

In the meantime you might want to check out JavaCPP: https://github.com/bytedeco/javacpp

Maybe you can use JavaCPP?

Here is the code for JNI, which uses the prebuilt JavaCPP library to call the getpid function. We don't have to write all the manual C binding code and rituals as the JavaCPP library already does it.

Javacpp is the best ffi library of all https://github.com/bytedeco/javacpp

As for our approach, we maintain a library called javacpp: https://github.com/bytedeco/javacpp which proves a python wheel like experience where we distribute natively optimized c/c++ code (and even cuda accelerated code) as jar files on maven central. We also are able to develop with a python like experience by passing pointers around and other low level constructs directly allowing optimizations that you typically only get in c/c++.

https://github.com/bytedeco/javacpp

* it maps naturally and efficiently many common features afforded by the C++ language and often considered problematic, including overloaded operators, class and function templates, callbacks through function pointers, function objects (aka functors), virtual functions and member function pointers, nested struct definitions, variable length arguments, nested namespaces, large data structures containing arbitrary cycles, virtual and multiple inheritance, passing/returning by value/reference/string/vector, anonymous unions, bit fields, exceptions, destructors and shared or unique pointers (via either try-with-resources or garbage collection), and documentation comments*

I did not try myself, but for JNI maybe this could make lives easier? https://github.com/bytedeco/javacpp