Add string utils to core

[lsiepel]

The goal of this PR is to add some string utility methods to core. This way they are available to all the bindings and we can finally get rid of the remaining apache.common libs.

While doing so, it seemed many bindings make use of the same apache StringUtils methods. To prevent code duplication it might be better to get the most used ones merged into core.

For reference: openhab/openhab-addons#7722
I'll also create an issue and PR's to update the openhab-addons.

Closes: #3783

[holgerfriedrich]

It feels a bit like "yet another string utils library", but I can understand why you want to bring this into core.
It is up to core maintainers to decide if this should be included.

I have reviewed the PR from a code perspective and can give some technical input.
Overall two points: null handling is not yet consistent, and a few comments regarding performance.

[holgerfriedrich]

LGTM, thanks.

Consistency regarding Null annotations to be discussed with maintainers. I follow your argumentation regarding the drop in replacement. Maybe a more consistent interface would be worth the effort and pay off in the future.

[kaikreuzer]

I'm fine with adding those utils here - as long as we do not end up with a whole library in the end. 😆
Wrt nullability: My personal preference for such util methods would be to allow null values everywhere. But I'm also fine with a different decision. But in general I'd agree with @holgerfriedrich that it would make sense to apply the same logic for all of them.

@openhab/core-maintainers What's your position wrt this PR?

[lsiepel]

Both kai and holger suggested aligning the null handling, so i did. I hope we can get this merged so i can update the addon PR's to use this.

[holgerfriedrich]

Fine. Just added a few findings, mainly related to the examples given in javadoc.

[holgerfriedrich]

Thanks for implementing all the review comments!

My last point is about this:
I have the feeling that calling two methods capitalizeWords() and capitalizAllWords() is not right way. I assume that I would never remember correctly which one of them uses space or underscores as delimiter. It is also unexpected that both functions handle the remaining letters of the words differently (converting to lowercase or leaving as it is).

Though, I have no proposal for a better naming.

[wborn]

What's your position wrt this PR?

I'm OK with merging it if it's just a couple of utility methods.
Maybe the functionality also ends up in some newer Java version one day. 🙂

[J-N-K]

I'm fine with that.

[lsiepel]

Thanks for implementing all the review comments!

My last point is about this: I have the feeling that calling two methods capitalizeWords() and capitalizAllWords() is not right way. I assume that I would never remember correctly which one of them uses space or underscores as delimiter. It is also unexpected that both functions handle the remaining letters of the words differently (converting to lowercase or leaving as it is).

Though, I have no proposal for a better naming.

The method nameshave been improved. Let me know if they need to be further adjusted or this can be merged.

[holgerfriedrich]

LGTM

[kaikreuzer]

Thanks, finally some StringUtils at our disposal again. 😄