Allow different global configs in the same jvm

[jonenst]

Describe the current behavior

Currently, there is -Dpowsybl.config.dirs or -Dpowsybl.config.name to allow switching the global configuration. This means it is possible to switch configuration between different JVMs.
But what if you need to switch configuration in a single jvm? The use case would still be to have static global configuration (not a 100% dynamic switch like in #2383 ).

Describe the expected behavior

I have no idea what this could look like unfortunately.

Describe the motivation

In my niche use case, I was using multiple wars deployed in the same tomcat so I wanted to scope the configuration to have warA use ~/.itools/configA and warB use ~/.itools/ConfigB

But I could imagine someone writing a program

main() {
  workA(); // tell users to configure this in configA.yaml
  workB(); // and this in configB.yaml
}

In many cases I think you can restructure the code to make it work but when you don't want to restructure the code you are stuck

Extra Information

No response

[jonenst]

maybe use java25 scoped values to hold the configuration ? I don't know, it seems dangerous because if you create a thread without using structuredtaskscope, you don't inherit the configuration and it may be hard to notice and produce subtle bugs

[jonenst]

https://mail.openjdk.org/archives/list/loom-dev@openjdk.org/message/XMJLNFVBZXA5C5DW5YVVTWTFFGA7ZV36/

Inheritance of ScopedValues is not compatibility with unstructured use
as there is no guarantee that the the lifetime of the ScopedValue
binding will fully enclose the lifetime of the "child" thread.
Although expensive, I suspect inheritable thread-locals (with copy
rather than sharing) is closer to what you are looking for.

So maybe InheritableThreadLocal is better for this use case (and it already exists since java 1.2)

[jonenst]

or allow to override in the Network Object which can often serve as context. And find a solution for all the places that don't run with the network in context