Formatting stream API methods on multiple lines.

[gaganis]

Hello all!

Firstly I would like to let you know that I really liked your project! I have found it out by working on JUnit5 and I love spotlessApply! No more hassle over formatting :)

Thanks and kudos for the great work!

---

One of the things that I would have liked to be better would be if we could also automate formatting of the stream API differently from other methods. In JUnit5 currently the formatter:off and on directives are used to achieve the format manually.

This how it looks now manually:

                // @formatter:off
		return findRepeatableAnnotations(this.testClass, Tag.class).stream()
				.map(Tag::value)
				.filter(StringUtils::isNotBlank)
				.map(TestTag::create)
				.collect(toCollection(LinkedHashSet::new));
		// @formatter:on

Ideally it would be really cool to get this automatically with spotless but I imagine this could be pretty difficult to implement.

Has this been discussed before?

I am willing to help with this but currently have no idea where to start.

Thanks
Giorgos

[jbduncan]

Hi @gaganis, welcome! As it turns out, I'm a committer for Spotless.

The only formatter we support yet that formats streams similarly to how JUnit 5's maintainers do it is google-java-format. I believe @sormuras is looking into migrating JUnit 5 from the Eclipse formatter to google-java-format, but I can't seem to his branch ATM.

I do wonder perhaps if the Eclipse formatter has a setting that allows streams and fluent constructs to be formatted like this. @nedtwigg, do you know of any such setting?

If such a setting doesn't exist, I'd be happy to see this feature implemented. But as I know of no library which could do it, and neither do I know the technical details on formatting Java code, I've no idea where to start either.

[sormuras]

...deleted the proof-of-concept branch, as we don't want to touch the entire JUnit 5 code base just for re-formatting. May be later, if/when google/google-java-format#19 is fixed, I might reconsider putting that topic on the table, again.

[gaganis]

Well I was thinking more about using spotless for some of my own projects and I do prefer the one-per-line indented formatting.

So I could get close to that formatting using spotless along with google-java-format?

[jbduncan]

Yes, I think so @gaganis.

[nedtwigg]

google-java-format is a good way to go. If you're not happy with it, the eclipse formatter has a bazillion settings. Dunno if there's a combination of checkboxes that does exactly what you want, but I bet there is. Here are the docs.