Exposing DumperOptions in Jackson's YAML handling.

jackson_yaml_configuration.kt

// See article for context: http://www.geekinasuit.com/2020/09/jackson-yaml-and-kotlin-data-classes.html

// Licensed under the MIT license described here: https://choosealicense.com/licenses/mit/
// Copyright (c) Square, Inc.

val jacksonMapper = YAMLMapper(MyYAMLFactory()).apply {
    registerModule(KotlinModule())
    setSerializationInclusion(JsonInclude.Include.NON_EMPTY)
  }
)

// I left the constructor parameters nullable deliberately
class MyYAMLGenerator(
  ctx: IOContext?,
  jsonFeatures: Int,
  yamlFeatures: Int,
  codec: ObjectCodec,
  out: Writer?,
  version: DumperOptions.Version?
): YAMLGenerator(ctx, jsonFeatures, yamlFeatures, codec, out, version) {
  override fun buildDumperOptions(
    jsonFeatures: Int,
    yamlFeatures: Int,
    version: Version?
  ): DumperOptions {
    return super.buildDumperOptions(jsonFeatures, yamlFeatures, version).apply {
      defaultScalarStyle = ScalarStyle.LITERAL;
      defaultFlowStyle = FlowStyle.BLOCK
      indicatorIndent = 2
      nonPrintableStyle = ESCAPE
      indent = 4
      isPrettyFlow = true
      width = 100
      this.version = version
    }
  }
}

class MyYAMLFactory(): YAMLFactory() {
  @Throws(IOException::class)
  override fun _createGenerator(out: Writer, ctxt: IOContext): YAMLGenerator {
    val feats = _yamlGeneratorFeatures
    return MyYAMLGenerator(ctxt, _generatorFeatures, feats, _objectCodec, out, _version)
  }
}