fix #1076: Add support for palantir-java-format

[carterkozak]

What

palantir-java-format is a modern, lambda-friendly, 120 character Java formatter based on the excellent google-java-format, and benefits from the work of all the original authors. palantir-java-format is available under the same (Apache 2.0 License)[https://github.com/palantir/palantir-java-format/blob/develop/LICENSE].

Examples from the readme

(1) before:

private static void configureResolvedVersionsWithVersionMapping(Project project) {
    project.getPluginManager()
            .withPlugin(
                    "maven-publish",
                    plugin -> {
                        project.getExtensions()
                                .getByType(PublishingExtension.class)
                                .getPublications()
                                .withType(MavenPublication.class)
                                .configureEach(
                                        publication ->
                                                publication.versionMapping(
                                                        mapping -> {
                                                            mapping.allVariants(
                                                                    VariantVersionMappingStrategy
                                                                            ::fromResolutionResult);
                                                        }));
                    });
}

(1) after:

private static void configureResolvedVersionsWithVersionMapping(Project project) {
    project.getPluginManager().withPlugin("maven-publish", plugin -> {
        project.getExtensions()
                .getByType(PublishingExtension.class)
                .getPublications()
                .withType(MavenPublication.class)
                .configureEach(publication -> publication.versionMapping(mapping -> {
                    mapping.allVariants(VariantVersionMappingStrategy::fromResolutionResult);
                }));
    });
}

(2) before:

private static GradleException notFound(
        String group, String name, Configuration configuration) {
    String actual =
            configuration.getIncoming().getResolutionResult().getAllComponents().stream()
                    .map(ResolvedComponentResult::getModuleVersion)
                    .map(
                            mvi ->
                                    String.format(
                                            "\t- %s:%s:%s",
                                            mvi.getGroup(), mvi.getName(), mvi.getVersion()))
                    .collect(Collectors.joining("\n"));
    // ...
}

(2) after:

private static GradleException notFound(String group, String name, Configuration configuration) {
    String actual = configuration.getIncoming().getResolutionResult().getAllComponents().stream()
            .map(ResolvedComponentResult::getModuleVersion)
            .map(mvi -> String.format("\t- %s:%s:%s", mvi.getGroup(), mvi.getName(), mvi.getVersion()))
            .collect(Collectors.joining("\n"));
    // ...
}

How

This implementation is nearly identical to the google-java-format implementation, given that palantir-java-format is a fork! I've avoided coupling the implementations, as that's more likely to cause harm than help, especially given the logic around version checks for supported features.

One difference between the implementations is that I have opted not to support reflowing strings. Currently the palantir-java-format library does not expose the reflowing method as public API, so it would have to be implemented using a different method such as Formatter.formatSourceAndFixImports.

---

PR metadata

• Please DO NOT FORCE PUSH. Don't worry about messy history, it's easier to do code review if we can tell what happened after the review, and force pushing breaks that.
• Please make sure that your PR allows edits from maintainers. Sometimes its faster for us to just fix something than it is to describe how to fix it.
• After creating the PR, please add a commit that adds a bullet-point under the [Unreleased] section of CHANGES.md, plugin-gradle/CHANGES.md, and plugin-maven/CHANGES.md which includes:
  • a summary of the change
  • either
    • [] a link to the issue you are resolving (for small changes)
    • a link to the PR you just created (for big changes likely to have discussion)
  • If your change only affects a build plugin, and not the lib, then you only need to update the plugin-foo/CHANGES.md for that plugin. If your change affects lib in an end-user-visible way (fixing a bug, updating a version) then you need to update CHANGES.md for both the lib and all build plugins. Users of a build plugin shouldn't have to refer to lib to see changes that affect them.

[carterkozak]

It looks like test_nomaven_11 Failed with java.lang.OutOfMemoryError: Metaspace. I don't believe this is related to my change, however I don't have permissions to 'rerun from failed' in circle. I can push an empty commit if that's preferred.

[nedtwigg]

You've gotta pick whether you're staying compatible with GJF or going your own way :)

[carterkozak]

That's fair, I can remove the extra bits, and trim down the API :-)

[nedtwigg]

Looks great!

[carterkozak]

Thanks for the review!

[nedtwigg]

I'm gonna give this ~24hrs in case anyone else wants to weigh-in and then I'll merge and release.

[nedtwigg]

Welp, jcenter is down today (semi-scheduled), which has brought the Gradle plugin portal down. https://discuss.gradle.org/t/plugins-redirecting-to-jcenter/41909/4

This PR is confirmed to pass all tests before the Gradle outage, so I'm moving forward with merging.

[nedtwigg]

Released in plugin-gradle 6.2.0 and plugin-maven 2.20.0.